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International Journal of Plant Breeding and Genetics

Plants of Celosia argentea var. spicata were treated with 0,
1000, 2000, 3000 and 4000 ppm. Dimethyl Sulphate (DMS) solution as soil drench
to study the effect of DMS on the plant growth and phytochemical composition.
Also, to produce new patterns of vegetative and flowering growth and identify
them using Inter Simple Sequence Repeat (ISSR) markers. The concentration of
3000 ppm increased significantly the number of leaves, concentration of anthocyanin
in the leaves and inflorescences in both generation and the concentration of
phenols in the M2-generation. The treatments of 1000, 2000 and 3000
ppm increased significantly the concentration of alkaloids in the M2
generation. All treatments decreased significantly stem diameter, length of
the inflorescence, delayed flowering in both generations and decreased plant
height in the M1-generation and chlorophyll content in the M2
generation. Changes of leaf and inflorescence shape were found in the M2
generation. The treatment of 3000 ppm produced one plant with bigger growth
in the M2 generations. Dwarfed plants were also obtained after treatments
of 2000, 3000 and 4000 ppm. Plants with green vegetative growth, yellow nods
and lacks of anthocyanin pigments were produced in the M1 generation
after the treatment of 3000 ppm and inherited in the next generation. The percentage
of polymorphism of the amplified products was 41.8%. UPGMA dendrogram program
classified the samples into two large clusters. The control sample was grouped
in cluster I and the five mutants were grouped in cluster II. 2014/04/18 - 19:47

Fifteen inbred lines and three testers of maize were crossed in line x tester
scheme to study the combining ability effects for earliness, grain yield and
yield components. A yield trial included the 45 top crosses, 15 inbred lines,
3 testers and two check hybrids S.C. Pioneer 3084 and T.W.C Giza 352. The experiment
was conducted for three years at the Agricultural Research Station of the Faculty
of Agriculture, Moshtohor, Benha University. The experimental design was randomized
complete blocks with three replications. Mean squares due to crosses (C) inbred
lines (L), testers (T) and line x tester (LxT) were significant for most studied
traits for the combined analysis over two evaluation seasons. Significance of
interaction variance for C, L, T and LxT with seasons on most studied traits
was detected. δ2SCA played the major role in determining
inheritance of all traits, revealing that the largest part of the total genetic
variability associated with these traits was a result of non- additive gene
action. The magnitude of the interaction of δ2SCAxyears
(SY) was generally higher than for δ2GCA x SY.
This indicates that non-additive type of gene action is more affected by SY
than additive and additive x additive types of gene action. Inbred lines M L4,
8, 9, 10, 11 and L12 were reliable general combiners for earliness and M L3,
4, 5, 6 and L13 for grain yield plant-1. For earliness the top-cross
M 212D x SC (M 201xM 204) gave the best Sij effects. Regarding grain yield plant-1,
five SC between M L 204 and each of inbred lines M 232A, M 202C, M 242A, M 212D
and M 236B as well as the two TWC M 202cxSC (201x204) and M 236BxSC (201x204)
showed significantly and out yielded than check hybrid SC Pioneer 3084 by 18.99%, 12.67%, 15.71%, 11.29%, 14.11%, 10.55% and 6.56% in the combined analysis,
respectively. 2014/04/18 - 19:47

Linseed (Linum usitatissimum), or common flax, is a useful plant that has been cultivated for thousands of years. Its oil is rich in omega-3 fatty acids, especially Alpha-Linolenic Acid (ALA) (C18:3) that was beneficial for heart disease, inflammatory bowel disease, arthritis and a variety of other health conditions. Nine linseed (Linum usitatissimum L.) genotypes were evaluated in randomized complete block design with three replications during 2011 main cropping season at six locations to determine the pattern of genotype by environment interaction of yield and yield related traits to identify the most stable linseed genotypes for wide and/or narrow adaptations. Combined analysis of variance (ANOVA) indicated significant variations among environments and among genotypes, indicating the existence of variability among the tested genotypes. Debark was the most suitable environment for seed yield, oil content, oil yield and most important fatty acid alpha-linolenic acid. Genotype by Environment Interaction (GEI) was statistically significant only for days to flowering, days to maturity and seed per capsule, indicating the importance of stability analysis. Additive main effect and multiplicative interaction (AMMI) stability analysis in this study selected Kulumsa-1 as stable genotypes for seed per capsule. Linseed adapts to North West Amhara Region, Ethiopia although differences were observed among genotypes. According to the combined analysis of variance for seed yield, oil content, oil yield and alpha-linolineic acid variety Kulumsa-1 can be used for wider cultivation to the North West Amhara Region, Ethiopia. 2014/04/18 - 19:47

Forty nine anchote (Coccinia abyssinica (Lam.) Cogn.) accessions were planted in simple lattice design at Bako Agricultural Research Center in 2011 to estimate components of variability, heritability, genetic advance and association among quantitative traits. Highly significant difference (p≤0.01) and wider range of variations were observed for most of the characters. High genotypic coefficient of variation along with high heritability and genetic advance was obtained from hundred seed weight, number of seeds per fruit, number of fruits per plant, root yield per plant, total root yield, marketable root yield and average fruit yield, showing the possibility of anchote yield improvement through selection. However, the rest characters showed low genetic variability, heritability and genetic advance under selection. Average root yield was positively and significantly (p<0.01) associated at genotypic and phenotypic level with root diameter (rg = 0.858 and rp = 0.593) and it also showed positive and highly significant association with root length (rg = 0.482 and rp = 0.345) signifying that indirect improvement would be very effective. Further evaluation including more accessions at different locations is suggested for having appropriate information. 2014/04/12 - 23:54

The aim of the experiment was to assess the relatedness of 118 cowpea genotypes
assembled based on 16 morphological traits and to identify genotypes with unique
traits for breeding purposes. The genotypes were from different parts of Ghana
as well as International Institute of Tropical Agriculture in Nigeria and University
of California Riverside in the United States of America. The phenotyping was
done in the experimental farm of West Africa Centre for Crop Improvement, University
of Ghana in April to June, 2011. Some of the traits include: Terminal leaflet
shape, number of seeds per pod, 100 seed weight, growth habit, days to flowering,
plant pigmentation and number of pods per peduncle, based on key access and
utilization descriptors for cowpea. Variability was observed in all of the 16
traits and was used to calculate dissimilarity between the genotypes with the
method of Sokal and Sneath. The dissimilarity ranged from 7-100% with a mean
of 43%. Factorial plot clustered the improved varieties together indicating
that they have been selected based on similar traits pointing the importance
of conservation in safeguarding genetic erosion. Diversity observed in the collection
based on the 16 traits would be of use in selecting parents for genetic studies
and breeding. 2014/04/12 - 23:54

Hybrid rice systems are based on three line Cytoplasmic Male Sterility (CMS) which has been an efficient tool in commercialization of hybrid rice technology. Therefore, identification of potential restorers in rice is the basic step in development of rice hybrids. In present study, 70 drought tolerant lines were crossed to two cytoplasmic male sterility lines viz., IR58025A and IR79156A and F1s were analyzed for pollen fertility (1% I-KI solution) and spikelet fertility. Based on the fertility restoration in F1’ s, 25 genotypes were restorers. Highly significant correlations of 0.93 and 0.88 between pollen fertility and spikelet fertility were obtained in hybrids involving CMS line IR 58025A and CMS IR 79156A, respectively. KMR 3, IR 84891-B-112-CRA-15-1 and IR79906-B-192-2-2 produced F1s with highest pollen fertility and spikelet fertility and are considered as promising restorers. 2014/04/12 - 23:54

Cowpea seed coat colour is one of the important consumer traits of the crop
in West Africa. The objective of the study was to find out the ratios of different
seed coat colour types that would segregate from crosses involving cowpea genotypes
of different colours. This would enable breeders to anticipate seed coat colours
that would result in segregating populations and also help in estimating the
number of genes controlling the trait. Six different bi-parental crosses were
made and the resulting seeds grown to F1 plants. Seeds were harvested
from F1 plants and grown on the field. An average of 250 plants was
studied within each segregating population. The number of seed coat colour phenotypes
produced varied from two for Bambey 21/Gbode to ten for Bambey 21/Tona. Individuals
of some of the populations could not be classified based on seed coat colour
as they exhibited continuous variation and therefore Chi-square goodness of
fit test could not be conducted on them. It is suspected that many genes might
be involved in seed coat colour inheritance in cowpea and as such the use of
molecular and quantitative principles may be helpful in understanding the genetic
control of the trait. 2014/04/12 - 23:54

This review is about the contribution of plant breeding to sustainable agriculture.
This contribution is based upon three main pillars: (i) The enrichment of the
source material with landraces and old cultivars, accompanied by a breeding
methodology based mainly on yield components, (ii) The screening of cultivars-parents
and the choice of crossing according to their genotypic profile, proved through
a series of criteria and (iii) The selection pattern applied in segregating
generations, based on an individual plant performance as a unit of selection
and evaluation. Comparable evaluation of progenies requires concurrent selection
among and within progenies and application of high selection pressures. This
selection procedure reduces genotype x environment interaction and increases
heritability. A number of experiments as paradigms have been included throughout
the text to better understanding. Breeding assumptions such as decentralized
selection and participatory plant breeding have been accepted and incorporated
in developing selected cultivars of low-input demands. The text as a whole follows
a logical course, from source material, through breeding techniques and selection
patterns to maximize heritability and efficiency offering in this way a sound
solution in sustainable agricultural problems. 2012/11/30 - 20:33

Grain yield and oil content of sesame are usually low, depending on genetic
variability and association of relevant characters with grain yield and oil
content. Hence, the objectives of this research were estimating the genetic
variability and association among characters. Eighty one sesame genotypes were
tested in 9x9 simple lattice design at Kebabo Tsegede wereda Western Tigray,
Ethiopia in 2010/11 cropping season. Analysis of variance revealed that there
was highly significant (p<0.01) difference among the 81 genotypes for all
the 15 characters studied. High genotypic and Phenotypic Coefficient of Variation
(PCV) was recorded for harvest index, seed yield/ha, height to first capsule,
biomass/ha, number of capsules/ha, number of primary branches/ha, number of
seeds per capsule and plant height. Height to first capsule had the highest
heritability value. High heritability coupled with high expected genetic advance
as percent of mean was observed for number of primary branches per plant, height
to first capsule and harvest index. This indicates that these characters can
be improved through selection. Harvest index showed positive significant phenotypic
and genotypic correlation with grain yield. Genotypically, path coefficient
analysis based on grain yield as a dependent variable revealed that capsule
filling period by days to 50% flowering and biological yield exerted positive
direct effect on seed yield. Therefore, a greater emphasis should be laid on
these characters in perspective of breeding programs. 2012/11/30 - 20:33

The longevity of seeds in storage is a good indicator of seed quality and vigour
in many crops. This study examined the physiological and genetic integrity of
nineteen amaranth accessions during storage. Seeds of each accession were subjected
to Artificial Ageing (AA) in an oven at 45°C and 80% RH for 3, 6, 24, 27,
48, 51 and 72 h for viability and vigour tests. Also, the seeds were placed
in a cotton bag and kept in a seed store, under ambient conditions for 6 months.
Stored seeds were tested for viability and vigour at 30 day interval. Furthermore,
electrophoresis analysis was conducted on seeds of three accessions to investigate
the total protein bands after AA and ambient storage for 6 months. The result
revealed that after 3 months of storage under ambient conditions, viability
and vigour reduced from 41.67-28.25% and 2.37-0.66%, respectively. Seeds progressively
declined in viability and vigour after 24-27 h of ageing from 28.42-2.89% and
1.54-0.12%, respectively. Accession NG/AO/11/08/123 had the best storage potentials
(P50 = 24 h) and (P50 = 150 days) under ambient storage
conditions. In accessions (NG/AO/08/123 and NG/AO/09/024), intensity of profile
staining was optimal at 24 h ageing maintained profile intensity for the 72
h. These periods correspond between 30 and 60% germination and vigour index
of 2.3, suggesting that Amaranth seeds begin to lose genetic integrity when
germination capacity is below 40%. Storage under ambient conditions should not
exceed 3 months for best performance of amaranth seeds. 2012/11/30 - 20:33

Drought and Striga are some of the key constraints to cowpea production. These
are further aggravated by the ever changing global climate and the concomitant
effects such as erratic rainfall pattern. This research was conducted to identify
lines that are tolerant to drought and resistant to Striga in one of
the major cowpea belt in West Africa. Twenty two genotypes of cowpea obtained
from the Cowpea Breeding Programme of the Institute for Agricultural Research
(IAR), Ahmadu Bello University Zaria, Nigeria were evaluated in 2 different
dates; beginning of the rainy season representing optimum moisture (7th August)
and the end of the rainy season representing drought conditions (7th September)
for two years (2008 and 2009). IAR-07-1050 was found to be resistant to Striga
although susceptible to drought (DRI = -0.32). Others genotypes were infested
by Striga. Two genotypes, IT98K-412-13 and IT93K-452-1 with DRI = 1.79
and 1.88, respectively were drought tolerant genotypes. IT99K-529-1, Biu Local,
Kanannado, IT99K-216-24-2, Sa Babba Sata, IT96D-610 and IT97K-819-118 showed
some level of tolerance as indicated by several selection indices including
DRI. These indices were very suitable for the identification of drought tolerance
in cowpea. DRI and DSI are particularly useful in the classification of genotypes
in terms of drought tolerance irrespective of their yield potential. This is
highly desirable for the identification of gene sources for further improvement
of cowpea for drought tolerance or in combination with other traits. 2012/11/30 - 20:33

Until recently, bunch and nut yield has dominated the previous coconut breeding
programmes in Nigeria. With the outbreak of Awka wilt Lethal Yellowing Disease
(LYD), research focus in coconut breeding has been drastically changed due to
decline in yield and the high susceptibility of the local land race, the West
African Tall (WAT). Hence, the evaluation of the comparative performance of
different coconut varieties surviving under natural field conditions in an LYD
endemic area of Nigeria. Five coconut varieties (Malayan Green Dwarf (MGD),
Malayan Yellow Dwarf (MYD), Malayan Orange Dwarf (MOD), WAT and Hybrid (HY)
varieties) derived from the Nigerian Institute for Oil Palm Research (NIFOR)
Tall and Exotic Malayan Dwarf parents were evaluated for bunch and nut production
for a period of seven years. Data was subjected to simple measures of variability
while the pattern of variation was deduced using Spearman’s
rank correlation coefficient. The results indicate that the surviving palms
in the respective varieties are vigorous with the dwarf varieties showing more
resistance to LYD when compared with WAT. However, WAT recorded the highest
yield (8.1 and 63.7) for bunch and nut production, respectively. Very high variation
ranging from 13.5-16.8% was observed for nut yield. Evidence of biennial rhythm
was revealed among the palms across the years. The number of nuts/palm/year
and bunch production/palm/year was highest in year 2007 with a range of 42.2-83.8
and 7.2-8.6, respectively. The distribution of the measured traits was very
discrete in the WAT variety when compared to the other dwarf varieties. The
rank correlation coefficient revealed very high significant positive coefficients
for bunch and nut yield. Despite the relatively poor performance of the varieties,
the high yielding palms would be used in crossing programme for the production
of Breeders’ Test Materials (BTM)
for further testing whilst serving as a germplasm base for resistance breeding. 2012/11/30 - 20:33

Acacia raddiana (L.) Willd. is an African leguminous multipurpose tree species belonging to subfamily Mimosoideae, subgenus Acacia, highly valued for pods, leaves and gum production. This study estimated the genetic diversity within and among Moroccans populations of the species in the Agdz, N’Koub, Tazarine, Mceissi, Tata, Tissint, Foum Zguid, Gluemim, Msceid and Assa provenances based on 9 quantitative traits which included; Pod Length (LP) (cm), Pod Width (WP) (mm), Pod Weight (WtP) (g), Seed Weight per Pod (WtS P-1) (g), Empty Pod Weight (WtEpP) (g), Seed Number per Pod (SN P-1), Infected Seed Number per Pod (InSN P-1) and 100-seed weight (100-Wt) (g) and shapes of pods throughout two seasons. In the both seasons provenances N’Koub, Tazarine and Tissint present the best means for the majority of traits studied, indicating geographical structuring of the genetic variability but it remained much reduced. Analysis of traits in various forms has shown that purely morphological criteria are inadequate for the selection of the Acacia raddiana trees which had a range of quantitative characters. The various traits are not regularly correlated with pods quality; they appear strictly in a variety of combinations and relations with environmental conditions. In view of this, any attempt for selection based on morpho-metrics traits of the polymorphic species must fail. 2012/06/07 - 21:31

Florist’s chrysanthemum (Chrysanthemum morifolium Ramat.) belongs to the Asteraceae family and represents the second most important floricultural crop in the world. Unfortunately most genotypes are sensitive to aphids. Internode explants of 1581 and 4043 genotypes were incubated with A. tumefaciens strain AGL-0 containing pBIN plasmid with the npt gene as a selectable marker for kanamycin resistance and gcs gene as an aphicidal gene with rbcS promoter. Kanamycin resistant shoots were induced from internodes after 3 weeks. Finally, the shoots were rooted on MS medium containing 30 mg L-1 kanamycin. Incorporation and expression of the transgenes were confirmed by PCR and RT-PCR analysis. Genotype 4043 has been transformed in this study for the first time. Transformation frequency for GCS was 6.25 and 5% for genotypes 1581 and 4043, respectively. 2012/06/07 - 21:31

Black pod and Canker caused by Phytopthora palmivora and Phytophthora megakarya and Cocoa Swollen Shoot Virus Disease (CSSVD) caused by cocoa swollen shoot virus are important diseases of cocoa in Ghana. Host plant resistance has been considered the most effective method of controlling these diseases. This study was initiated to determine whether multiple forms of resistance to these diseases could be identified in hybrids of cocoa. Thirty six crosses of 6x6 diallel mating design of cocoa were screened for resistance to black pod (P. palmivora and P. megakarya), CSSVD (severe New Juaben CSSV Strain 1A and Nsaba CSSV strain) and Phytophthora canker (P. palmivora and P. megakarya) under a controlled environment. Of the thirty six crosses, 12, 6 and 7 were resistant to black pod, cocoa swollen shoot virus disease and Phytophthora canker, respectively. No cross was found to have combined resistance to the three diseases. This indicates that selection and breeding of cocoa genotypes for multiple disease resistance based on phenotypic data alone could be difficult. Marker assisted selection using tightly linked gene-specific molecular markers will play a larger role in future studies and could be an asset in working with quantitative resistance systems. Cocoa hybrids Alpha B36xPa7/808, Pa7/808xPound 7 and Alpha B36xT65/326 which possess high levels of resistance to more than one disease were identified through this study and would be useful in cocoa multiple disease resistance breeding programmes. 2012/06/07 - 21:31

Success of semi-dwarf varieties in late 1960’s lead breeders to depend heavily on these leading to narrow genetic base in today’s rice varieties. Analysis of cultivated varieties in tropical Asia revealed sd1 gene from Dee-geo-woo-gen to be the major dwarfing source. High genetic similarity renders crop genetically vulnerable to potential epidemics. Efforts are underway to broaden the genetic base using alternate sources of dwarfing. Mutation breeding has been used to increase allelic diversity. In this study, twenty radiation induced mutants of rice (Oryza sativa L.) and parent variety WL112, showing morphological differences, were screened for variation in Simple Sequence Repeats (SSR). Thirty five polymorphic SSR primers, selected from all chromosomes of rice generated 115 polymorphic bands. Jaccard’s similarity coefficient revealed considerable genetic diversity among the mutants. The dissimilarity between the mutants was as high as 65%. The UPGMA based dendrogram showed five major clusters with sub-clusters. Mutant-specific polymorphic SSR markers either alone or in combination, were detected. Twelve mutants could be identified by using specific markers, while combination of two could identify six mutants and parent. The radiation induced mutants revealed diversity and short stature in elite background which could be used in breeding programme. 2012/06/07 - 21:31

The study was designed to characterize the genetic diversity in a set of rice genotypes with different adaptation to saline soil using microsatellite markers (SSR markers). For this analysis a total of 50 SSR primers across the 12 chromosomes were taken up out of these 50 primers, 37 primers were polymorphic. The average number of alleles per locus was 5.69, indicating greater magnitude of diversity among the plant materials. The average PIC value 0.732 conformed the markers used were highly informative. The cluster analysis grouped the 27 genotypes into nine clusters. Cluster I consisted of nine varieties and all are indica type. Cluster II consisted of three varieties all are salt tolerance. Cluster III consisted of two rice varieties these are tolerant to drought. Cluster IV consisted of seven varieties, which are high yielding varieties. Cluster V consisted of CR1009, which is high yielding variety. Cluster VI consisted of Pokkali and CSR23 both are highly tolerant to salinity. Cluster VII, VIII and IX are mono-clusters consisted of CSR27, CSR10 and Jeeragasamba. The maximum similarity value of 0.786 was observed between the varieties of IR36 and IR64 indicated that these were more closely related. The minimum similarity value of 0.237 was observed between the genotypes IR36 and CSR10 indicated that these two varieties were highly divergent. The varieties possessing high genetic distance value could be utilized for the development of high yielding varieties than the highly closed varieties. 2012/06/07 - 21:31

In the attempt of understanding the importance of the first generations in wheat breeding, a controversial experimentation procedure was used with F2 generation preceding F1. Ten bread wheat F2’s and their parents were evaluated in dense stand followed by the evaluation of the ten F1’s and their parents in isolation environment for two successive years. Three criteria groups were used; a) the heterosis of F1 and F2 according to their parents, b) the productivity and stability per se of F1 and F2 and c) the general/specific combining ability of parents. Heterosis alone proved of little significance in connecting the performance of both generations compared to standard check heterosis. The highest yielding F2 was the only cross exhibiting negative heterosis and heterobeltiosis in F1 while it was significantly higher in F2 and equal in F1 for standard check heterosis constituting it a safe criterion. The second criteria group indicated significant correlation between the stability of F1 and F2 with the productivity of the crosses in total being equal to each other giving another linkage factor between the two generations. The diallel analysis of both experiments pinpointed the importance of the information provided by the F2 generation thus constituting it far more valuable than the information of F1. The data indicated that non heterotic F1’s should not be discarded as a combined use of all the criteria can evaluate and discriminate more accurately the promising materials. 2012/06/07 - 21:31

Variability in crop traits creates options for breeders to develop improved cultivars. Many landraces of long cayenne pepper exist in Nigeria but none is recommended for cultivation. Collection, screening and conservation of landraces are therefore vital for the crop improvement. An experiment was carried out at the National Horticultural Research Institute, Ibadan, Nigeria, Latitude 7°22' N Longitude 3°58' E from April 2008 to March 2009 to investigate the extent of variation in reproductive pattern, reproduce-ability and morphology of flowers, fruits and seeds so as to determine markers suitable for pepper improvement. Seeds of long cayenne pepper collected from 25 locations in Southwestern Nigeria were extracted from the fruits, air-dried, bulked and packaged as accession from each location. Six week old seedlings of the pepper were transplanted into 3.6x2.4 m seed beds that were 1 m apart. The plants were spaced 60x60 cm. Plants of the first trial were rainfed; and of the second, were irrigated twice a week when rain stopped. Observations were on flower, fruit and seed traits. Data collected were subjected to analysis of variance combined, across the two trials and means significant were separated by Least Significant Difference. A wide diversity existed within the pepper species on flowering and fruiting pattern. Fruit wall thickness and pedicel length were suggested as morphological markers, number of fruit/plant and seed/fruit; not 1000-seed weight were suitable as markers to select variants for pepper improvement. Any of fruit length, fruit width and days to flowering and fruiting was efficient only when employed together with other markers. Time of cultivation had significant effect on days to first and 50% flowering and fruiting, fruit pedicel length, fruit/plant and fruit weight/plant; but not on fruit length, width and fruit wall thickness; number of seed/plant and 1000 seed weight. 2012/06/07 - 21:31

The objective of the study was to generate genetic information, which can help in breeding sweet melon cultivars with improved drought tolerance. Thirteen sweet melon genotypes collected from different places in Egypt were evaluated for variability, heritability and genetic advance. The experimental material was sown in a randomized complete blocks design with three replicates under irrigation as well as drought stress conditions. Significant differences were observed among genotypes for all the studied traits under normal irrigation and water stress. The irrigationxgenotypes interactions were found to be significant for all the studied traits except fruit length. The estimates of phenotypic coefficient of variation were higher than the estimates of genotypic coefficient of variation for all the characters, which suggested that the apparent variation is not only due to the genotypes but also due to the influence of environment. High heritability coupled with high genetic advance was noted for fruit weight and yield per plant. This provided that these parameters were under the control of additive genetic effects. This indicates that selection should lead to fast genetic improvement of the material. Moreover, magnitude of mean performance for all the traits decreased in water stress environment. Fruit length was very less affected by water stress, but yield per plant was very high affected by water stress. 2012/06/07 - 21:31

Cultivar discrimination of parental inbred lines is essential for genetic purity of F1 hybrid seed products. It is also essential for the purpose of maintenance of agronomic performance, variety registration, issuance of breeders’ rights, proper labeling of seed products and protection of investments in plant breeding. Digital imaging analysis had been identified as a fast and reliable method for variety discrimination and was applied in this study. With the aid of a digital imaging software (Veho™), 10 seed morpho-metric traits were digitally measured and/or calculated from captured images of 17 inbred lines drawn from the Striga-resistant tropical maize population. The seed metric data were subjected to Pearson’s correlation analysis, the Principal Component Analysis (PCA) and the Single Linkage Cluster Analysis (SLCA). All the parameters showed positive correlation except embryo angle, seed shape factor and circularity index. Seed area, length, perimeter and flatness index contributed the largest variability within the population (eigenvectors = 0.332, 0.328, 0.323 and 0.318), respectively, suggesting their potential usage for cultivar discrimination by digital imaging of maize seeds. Dendrogram constructed from the SLCA showed four major clusters of the inbred population. The clusters constitute a classification tool for future evaluation of genetic purity of test inbred and F1 hybrid samples within Striga resistant maize population. Results of this study demonstrated applicability of digital imaging for analysis of seed genetic quality and will ultimately improve the hybrid seed sector in Nigeria. 2012/06/07 - 21:31

Morphological characteristics of florets are of utmost importance in increasing the outcrossing rate in hybrid rice seed production. Among the different floral traits, stigma exsertion is considered to be of highest significance. Normally rice has stigma with two branches mentioned as bifid stigma. We reported a new natural mutant morphotype of stigma having an extra branch (hereafter mentioned as trifid stigma) which was identified in an indica maintainer line of rice. It occurs at a frequency of 0-35% in the population. Morphometric data showed that the extra branch is shorter than the other two branches of trifid stigma which were shorter than the mean length of bifid stigma. The possible use of the new variant in hybrid rice breeding is discussed. 2012/06/07 - 21:31

Combining ability for maturity traits was studied in pearl millet. Ten parents selected through a field screening technique for their different response to supra-optimal temperature tolerance were crossed in a diallel manner. Forty-five F1 hybrids along with their 10 parents were tested for their performance under supra-optimal temperature exposure at seedling stage with an objective to understand the nature of gene action and to identify parents for breeding programme. The experiment was conducted in three different environments created through different dates of sowing from May to July. The Griffings method of diallel analysis was used to obtain the genetic estimates. Variances due to general combining ability and specific combining ability for all the characters studied, viz., Seedling Thermo-tolerance Index (STI), Seed to Seedling Thermo-tolerance Index (SSTI), panicle emergence, effective tillers, plant height, ear length, ear weight, dry fodder yield, grain yield/plant and total biological yield/plant were highly significant in all the three environments (two stress and one normal) and on pooled basis indicating the importance of both additive and non-additive gene actions. The genotype CVJ-2-5-3-1-3 was identified as the best general combiner for STI as well as maturity traits, while, the genotype (77/371xBSECT CP-1) exhibited highest GCA effects for SSTI in both the stress environments. The genotype (77/371xBSECT CP-1) had high GCA effects for STI and SSTI as well as panicle emergence for earliness. Broad sense heritability (h2bs) was quite high for all the characters studied. However, the estimates of additive genetic variance and narrow sense heritability for STI and SSTI also indicated good chances of effective selection. Preponderance of non-additive (dominance component) was recorded for all the characters suggested the success of hybrid breeding by making use of the expected heterosis. Heat tolerance indices STI and SSTI were not showing any perceptible correlation with either of the maturity traits suggested that pearl millet has great resilience and recovery after stress period during seedling stage. 2012/02/11 - 13:26

The study was initiated to generate genetic information on characters associations for tomato genotypes maintained under Ethiopian conditions. Twenty three tomato (Lycopersicon esculentum Mill.) genotypes were evaluated to estimate the nature and magnitude of associations of different characters with fruit yield and among themselves at Bako Agricultural Research Center (Western Ethiopia) during October 2007 to May 2008. The experiment was conducted using a Randomized Complete Block Design with three replications. Yield per plant showed positive and significant genotypic and phenotypic correlation with fruit clusters per plant (rg = 0.448*, rp = 0.442*) and fruits per plant (rg = 0.505*, rp = 0.461*) which indicated that these traits play important role in yield improvement. Fruit clusters per plant showed positive and significant genotypic and phenotypic correlation with yield per plant by having positive direct effect at both levels, indicating the true relationship between them and the feasibility to exploit the potentiality of this trait for effective direct selection to improve yield per plant. Genotypic and phenotypic path coefficient analysis revealed that positive direct effects were exerted by days to flowering, fruit clusters per plant and plant height on yield per plant, suggesting their importance in yield improvement and that these traits would be considered in selection program. 2012/02/11 - 13:26

The present study was conducted to evaluate 45 hybrid rice along with currently available six semi-dwarf, early to mid-early duration and high yielding indicas (Govind, Manhar, Pant Dhan 4, Sarjoo 52, Pant Dhan 12 and Narendra 359) along with four tropical japonicas cultivars (BSI10, BSI16, B4116 and B4122) having wide compatibility gene(s), in relation to analyze gene action and heterosis for grain yield and associated traits. The experiment was conducted in randomized complete design and data collected on various traits were analyzed for heterosis and combining ability. Both additive and non-additive gene action were found to control the expression of all characters. The ratio of General Combining Ability (GCA) to Specific Combining Ability (SCA) variances exhibited greater relevance of non-additive gene action governing yield and its associated traits. Parent B4122 and Sarjoo 52 were found to be the best general combiner for maximum characters, including grain yield plant-1. The crosses B4116xSarjoo 52, BSI10xPant Dhan 12, BSI10xNarendra 359, B4122xManhar and B4122xGovind recorded the highest SCA effects for yield plant-1. Heterosis over mid-parent, better parent and standard variety ranged between -54.17 to 169.70, -58.31 to 150.32 and -64.55 to 146.15%, respectively. The trends of magnitude of heterosis for grain yield and plant height were I/J>I/I>J/J and for days to 50% flowering I/J>J/J> I/I hybrids. The crosses B4116xSarjoo 52, BSI10xPant Dhan 12 and BSI10xNarendra 359 were identified as the best hybrids on the basis of per se performance, high heterosis and combining ability effects. Most of the heterotic cross combinations identified in this study involved indica and tropical japonica lines having wide compatibility gene as their parents. Interspecific hybrids exhibited high heterobeltiosis and economic heterosis. 2012/02/11 - 13:26

Morpho-physiological characteristics of 12 genetically diverse cocoa genotypes with various levels of resistance were examined to determine which features were associated with resistance. The 12 cocoa genotypes were evaluated by leaf discs and detached pod inoculations for resistance to P. palmivora and P. megakarya. Pod husk thickness and epicuticular waxes on abaxial and adaxial surfaces of leaf and on cocoa pod surfaces were significantly and negatively correlated with resistance to black pod disease. Percentage moisture content was positively associated with resistance to black pod disease. Epicuticular wax on pod husk was significantly correlated with penetration resistance but however was not significant with post-penetration resistance suggesting its role in restricting penetration of the fungus. Principal Component Analysis (PCA) shows that the first two components contribute to explain 97.02% (PC1 = 87.87%, PC2 = 9.29%) of the total variation of morpho-physiological traits in cocoa. Amount of cuticular wax on pod surface, percentage moisture content of pod husk and leaf were the major contributors of total variation of morpho-physiological factors evaluated. Multiple linear regression analysis indicated that morpho-physiological traits explained 99.2, 91.2 and 81.3% of the variation in pod lesion number, pod lesion size and leaf disc score, respectively. This suggests that amount of wax on pod and abaxial surface of leaf, thickness of exocarp at the ridge and percentage moisture content could be used as marker traits to select for resistance to black pod disease. 2012/01/06 - 15:05

Introgression lines (IL) from crosses between elite cultivars and wild species are an important resource for mapping quantitative trait loci (QTLs) for yield. In this study, 25 KMR3-O. rufipogon ILs, from an advanced back cross population, were selected for high grain yield in field trials and characterized in detail for yield and related traits from seed to seed. The aim was to dissect the basis of high yield in the entire life cycle to identify common features in high yielding ILs. This study indicated that each IL has a different strategy or a combination of different yield traits to attain high yield. High yield in these ILs was associated with early flowering, high number of tillers, panicles, grains, seed weight per panicle and seed density. Seed germination rate, leaf SPAD chlorophyll meter value, plant height, panicle length and 100 seed weight did not have much impact on yield. Highest significant positive correlation was observed between number of tillers and number of productive tillers (0.98) as expected. A highest significant negative correlation was observed between seed density and seed compactness (-0.95). The new negative correlation between seed germination rate and leaf SPAD chlorophyll meter value in the top 10 ILs was supported by a non significant negative correlation (-0.17) in BC3F4 IL population and deserves further study. Restricting to a specific ideotype in selection may be counterproductive in rice breeding. These ILs are being used in rice improvement and to identify favorable genes from O. rufipogon for increasing yield. 2012/01/06 - 15:05

Six canola (Brassica napus) varieties were used in this study which was
chosen as a representative sample of commercial canola varieties used for oil
production. The objectives of this study were; 1) cluster the varieties understudy
using the morphological characters oil and protein percentages, 2) estimation
the genetic diversity among varieties understudy using RAPD markers, and 3) find
the correlation between RAPD and morphological diversity. Data showed that the
averages of all varieties for oil and protein percentages were 39.38 and 16.77,
respectively. Euclidean distances based on oil and protein percentages were calculated.
Their values ranged from 14.14 to 92.05 and the average of the distances was 42.9.
This data indicated that the amount of phenotypic variation among the varieties
was relatively high. The cluster diagram based on Euclidean distance separated
varieties into two groups. Also, data of the 10 random primers used indicated
a total of 401 scorable bands. Total amplified DNA fragments were 93 and number
of DNA fragments per primer varied from 6-13. Total polymorphic fragments were
55 with an average of 57.76% polymorphic fragment per primer. The similarity coefficient
values based on RAPD markers ranged from 0.114 to 0.261 with an average of 0.183.
The conducted dendogram showed that five varieties formed one main cluster. RAPD
results (81.7% divergence) indicated higher diversity than indicated by oil and
protein morphological markers (42.9%). Finally, Mantel test was calculated to
find out the correlation between RAPD markers and morphological characters matrices.
A lack of correlation was obtained (r = -0.08992) and many possible reasons were
discussed. 2012/01/06 - 15:05

The choice of an efficient breeding procedure depends to a large extent on knowledge of the genetic system controlling the character to be selected. To obtain information on the nature of gene action in West African okra, six generations of parents, first and second filial generations, back crosses 1 and 2 (P1, P2, F1, F2, BC1 and BC2) derived using Generation Mean Analysis (GMA) from crosses involving fourteen selected genotypes were evaluated. The experiments were conducted at the Teaching and Research farm of the University of Agriculture, Abeokuta (7°29N, 3°30E) during the growing seasons of 2008 and 2009. The data suggest that genes influencing some of the characters are dispersed among the parental lines and those interactions are predominantly of the duplicate kind. Additive gene effects were higher than dominance gene effects for most of the traits that were evaluated. Seed yield per plant for cross NGAE-96-0062-2 X CEN 015 was controlled by complementary gene action. Days to flowering, number of pods per plant, number of seeds per pod, matured plant height and seed weight per plant for the NGAE-96-0063 X CEN 015 cross was controlled by duplicate epistatic gene actions. The presence of significant amount of all types of gene action, additive, dominance and epistasis for most of the traits has indicated that methods designed to utilize all of them such as recurrent selection and reciprocal recurrent selection has to be adopted in the breeding programme. 2012/01/06 - 15:05

Pterocarpus angolensis is one of the most valuable timber trees in Tanzania currently extensively exploited. This study was conducted to obtain baseline information on its genetic diversity and population structure in order to formulate effective conservation plans. Random amplified polymorphic DNA (RAPD) markers were used to assess the genetic diversity in Pterocarpus angolensis DC. collected from six natural populations in eastern part of Tanzania. A total of 42 individual plants were analysed using 11 most informative RAPD primers which amplified 73 scored DNA bands showing 75.3% polymorphism. Cluster analysis is used unweighted pair group method with arithmetic average (UPGMA) formed three major clusters which illustrated that most individuals from a given population tended to cluster together and were therefore more genetically similar than individuals from different populations. Most of the genetic variations were found to be high within population 77.13% and low among populations 22.86%. The genetic diversity information of P. angolensis populations reported in this study is very important component for efficient conservation and effective management of its genetic resources. 2012/01/06 - 15:05

The Nigerian vegetable cowpea accessions differ in phenology with respect to their reactions to day-length. Some are Day Neutral (DN) while others are Short Day (SD) plants. Field experiments were therefore carried out to investigate possible influence of maternal effects on the inheritance of flowering time in cowpea. The distribution of the progenies with respect to days to flowering showed combine effect of both maternal and nuclear influence on the inheritance of flowering time in cowpea. The parental lines, F1, F2 and backcross populations differed significantly (p<0.05) in days to flowering and other yield traits assessed. Days to first and 50% flowering for SD accessions were delayed significantly (p<0.05) compared to DN accessions. The result of the principal component analysis revealed that the most effective characters for distinguishing the parents and progenies included days to first and 50% flowering, No. of peduncles plant-1, No. of flowers plant-1, No. of pods plant-1 and grain yield. The scatter plot and cluster means of the first two principal axes grouped the cowpea accessions into two main clusters. Cluster I comprised of early flowering (<45 days) DN cowpea accessions that were relatively poor in the yield traits assessed. Conversely, the cowpea accessions in cluster II were late flowering (>45 days) SD but prolific in grain and other yield attributes. The hybrids arising from these two groups of cowpea flowered irrespective of day-length, implying continuous podding and all-year-round harvest. 2011/10/29 - 12:09

Knowledge on variability and quality of durum wheat genotypes for pasta making as well as associations among quality parameters is important to design a suitable plant breeding program. Sixteen durum wheat genotypes were tested at Sinana and Adaba, Southeastern Ethiopia during 2009 bona season. The experiment was laid out in a randomized complete block design with three replications. Thirteen quality parameters were included in the study. Pooled analysis of variance revealed significant differences among genotypes for all quality parameters studied indicating the presence of variability. Genotypic correlation coefficient depicted important quality parameters are positively correlated with grain protein content, suggesting a common genetic basis among these traits and indicating the possibility of simultaneous improvement. Yellow pigment content showed the highest heritability value of 84.3% and gluten index had the lowest value of 3.8%. Dry gluten content (0.65**) and thousand kernel weight (0.26*) had the highest positive direct effect on grain protein content and significant positive genotypic correlation with grain protein content. Hence these traits are important as selection criteria for improvement of grain protein content in durum wheat. Protein content of the genotypes ranged from 10.7% (CDSS94) to 13.2% (Leliso). The study also showed variations in gluten strength as measured by alveograph strength W ranging from 64.3x10-4 J (Gerardo) to 187.6x10-4 J (Hitosa). Considering the performance of genotypes across most quality parameters, all the studied genotypes except Gerardo, Oda and Cocorit-71 were superior and could also serve as donor sources in durum wheat breeding programs for good pasta making quality. 2011/10/29 - 12:09

Female telfairia produce succulent and fleshy leafy vegetables with higher nutritional values than male type and therefore preferred at groceries. There is difficulty in identifying this female telfairia at seed and seedling stages. This research identified effect of seed position and fruit origin on the vigor performance and sex ratio of Telfairia occidentalis. Three seed positions of anterior, middle and posterior sections of fruits sourced from four origins of growth were studied in the nursery and field plots at the teaching and research farm of Ladoke Akintola University of Technology, Ogbomoso, Nigeria. Vigor index and percentage emergence were highest for seedlings from the anterior portions with fruits sourced from Imo and Ibadan origins. Genotypic Coefficient of Variation (GCV) and Heritability estimate in the broad sense (HB) for branching, foliage, vine length and diameter traits were also high for plants developed from anterior seed positions and therefore can be reliably selected. More female plants were sighted to have developed from the anterior positions with 3:1 and 2:1 female to male proportions for fruits sourced from Imo and Ogbomoso origins. There were difficulties in obtaining exact genetic sex ratios. This is attributed to differences in flowering time in the male and female plants. Fruits sourced from humid environment of Imo state and seeds extracted from anterior position, recorded highest seedling vigor performance and high female to male proportions for the field established plants. These findings affirm the postulation that more female plants develop from anterior seed positions if sourced from humid agro-ecologies. 2011/10/29 - 12:09

Assessing variability is fundamental to identify the most important traits in tef improvement program. The objective of the present study was to estimate variability, heritability and genetic advance on sixteen morphological characters in tef (Eragrostis tef (Zucc.) Trotter). Forty-nine genotypes were evaluated at two locations of Bale in south east of Ethiopia in 2008 cropping season. Simple lattice design of 7x7 with two replication was used to test the treatments. Pooled ANOVA of the two locations showed highly significant (p<0.01) for days to panicle emergence, lodging percentage, thousands kernel weight, grain yield per plant and grain yield per hectare. Significant differences (p<0.05) were noted for panicle length, shoot biomass and number of branch per main panicle. Genotype by location interaction was none significant for all traits which indicated that performance of the genotypes were consistent for these traits across the test locations. High phenotypic coefficient variation were observed for thousand kernel weight (78.82), productive tiller (46.45) and grain yield per plant (34.15) while high genotypic coefficient of variation were noted for traits, thousand kernel weight (40.34), productive tiller (32.46) and grain yield per plant (21.18). Maximum heritability estimate were observed for days to panicle emergence (75.50%) and grain filling period (66.79). High genetic gain was observed for lodging (10.90%) and days to panicle emergence (8.05%). The study showed that there are variation in extent of variability, heritability and genetic advance in traits under study which can facilitate selection for further improvement of important traits in tef. 2011/10/29 - 12:09

The precarious and worsening climatic and weather conditions being experienced in the globe today poses a threat to food security. Thus, there is a need for an urgent search for crops with intrinsic capacity to withstand the stressors and still perform well productivity-wise. The present study focused on the estimation of genetic variability and heritability of morphological traits in four cowpea landraces-akidi, olaudi, ileje ajaka and ileje with the aim of improvement. Seeds of the landraces were obtained from dealers in Enugu and Kogi States, Nigeria, respectively and sown on a plot of land measuring 10x10 meters at the University of Calabar Experimental Farm, Calabar during 2010-2011 growing season. A randomized complete block design was adopted during the planting. Variance estimates, genetic advance and heritability of yield and yield-related traits were estimated. The mean morphological and yield performance showed that there were significant differences (p<0.05) in all the parameters studied except days to 50% seedling emergence with “olaudi” variety maturing fast and having the highest seed yield. The results present high and wide genetic variability in the vein length per plant, number of leaves per plant, leaf area, number of flowers per plant, days to 50% maturity and seed yield. Genetic advance were considerably low but with high heritability estimates in all the traits investigated. The results explicitly revealed that there are sufficient genetic variations to encourage the improvement of these orphan crops. 2011/10/29 - 12:09

This study was explored in order to determine the effects of various agronomic traits on single plant seed yield in sesame using correlation and path coefficient analysis. Nine diverse accessions of sesame were grown in a two-year potted field experiment and were completely randomized with twelve replicates. Simple correlation and path analysis were carried out in order to determine the relationships between agronomic characters and estimate their direct and indirect influences on the single plant seed yield. Positive and statistically significant (p<0.01) relationships were established between single plant seed yield (g) and leaf nodes per plant, number of pods per plant, number of pods per main stem, breadth of pod, number of seeds per pod, 1000-seed weight and number of seeds per plant. Path analysis revealed that the number of seeds per plant and 1000-seed weight had the highest direct influence (i.e., 1.325 and 0.578, respectively) on single plant seed yield while the number of pods per plant had the highest indirect effect (1.175) through the number of seeds per plant. These results indicate that number of seeds per plant, 1000-seed weight and number of pods per plant can be good selection criteria for single plant seed yield in sesame. 2011/08/18 - 22:58

Physical dimensions of nine morphologically distinct sesame seeds were determined in order to access the extent of variability for size. Length, width and thickness of nine accessions of sesame comprising six cultivated and three wild relatives were measured using micrometer. Other parameters were calculated using standard mathematical procedures. Mean seed length ranged from 2.65 to 3.77 mm, mean seed width from 1.49 to 2.84 mm and mean seed thickness from 0.61 to 1.28 mm. Seed geometric diameter varied from 0.81 to 3.91 mm3 while surface area varied from 2.43 to 48.66 mm2. Principal component analysis divided the 11 variables determined into two components which explained 88.96% of the total variation. First component (56.23%) strongly influenced seed geometric diameter, sphericity, thickness, surface area, length-thickness ratio and length. Second component (32.73%) was affected strongly by width-thickness ratio, 1000-seed weight, length-width ratio, seed oil content and width. The dendrogram generated by the un-weighted pair group method using arithmetic averages (UPGMA) cluster analysis grouped the nine accessions into five distinct clusters indicating genetic diversity. This information can be used to design processing and handling machine for sesame seeds and also to plan crosses in order to maximize the expression of heterosis for large seed size. 2011/08/18 - 22:58

Several biometrical methods available for the analysis of gxe interaction and yield stability, often fail to provide an accurate picture of complete response pattern of the genotypes because the stability indices are usually univariate. The objective of this study was to examine the various statistical methods for stability analysis of bunch yield in order to determine their congruence in identification of stable oil palm genotype. Fifteen duraxtenera oil palm genotypes were evaluated for genotype by environment interaction (gxe) and yield stability across four environments. The five statistical methods examined are Eberhart and Russell joint linear regression (ER), Shukla’s Stability index (SH), Francis and Kanennberg genotype-grouping technique (FK), Lin and Binn’s cultivar superiority values (LB) and Yan’s Genotype and Genotype by Environment interaction model (GGE). Significant crossover gxe interaction was observed, suggesting specific adaptation. Spearman’s rank correlation coefficient between the stability parameters and environments indicated a weak relationship. However, SH was significantly correlated with ER and LB. The level of convergence between any two methods ranged from 25 to 67% while that among three, four or the five methods were between 29 to 57%. Two genotypes, DT7 and DT11 were identified as high yielding and stable by all methods. These genotypes would be reliable for future breeding programme to develop high yielding planting materials with stable performance. Furthermore, farmers will be assured of the yield from season to season. In most cases, genotypes selected by GGE were also classified as stable by the other four methods. Thus, simultaneous use of stability statistics would protect the breeder from making wrong selections. 2011/08/18 - 22:58

The objective of this study was to observe pattern of similarity of reaction to Phytophthora palmivora infection among 25 international cocoa genotypes in five laboratory experiments and a field observation at the Cocoa Research Institute of Ghana by hierarchical cluster analyses. The genotypes were clustered into two distinct populations in all the screening methods suggesting of genetic limitations of the cocoa genotypes studied. The hierarchical cluster analyses of all the screening tests sub-clustered the susceptible and resistant clones differently except in field infection where there was some inconsistency. This is indicative of the possibility of using any of the screening methods to observe similarity of reaction of cocoa genotypes to Phytophthora species. The inconsistencies in field infection are suggestive of the environmental factors influencing the genetic base of infection of Phytophthora species in the field. The resistant and susceptible genotypes were distributed among centres of origin and genetic groups showing that resistant and susceptible genotypes were widely dispersed among origins and genetic groups. The shapes of pods of resistant genotypes were made up of calabacillo and cundeamor while that of susceptible clones was Amelonado. The remaining of the clones, classified as moderately resistant were the most distantly related clones. 2011/07/09 - 13:14

The overall aim of this study was to study the extent of genetic variation and association among bean physical, organoleptic and biochemical quality traits. Twenty-one native coffee germplasm collections were evaluated for 16 quality traits in randomized complete block design at the Jimma Research Center. Variances component method was used to estimate genetic variation, broad sense heritability and genetic advance. Association of traits was also estimated using standard method. The genotypes differ significantly (p<0.01) for most coffee quality and biochemical attributes. Coffee collections from Sheko, Dizi and Meanit manifested high variability for sensorial and biochemical characters as compared to those from other origins. Aromatic intensity, flavour, bitterness, shape and make, average bean weight, dry matter, ash, protein and fat had expressed high heritability. The relationships between the attributes were observed to vary in patterns and magnitudes both at phenotypic and genotypic levels. The good cup quality parameters had reverse relationships with caffeine, bitterness and astringency at phenotypic level, indicating that coffee breeding strategy within and among geographical areas may provide quality improvement with known origin quality profile. It can be concluded that the promising coffee germplasm collections were diverse in terms of most quality traits and biochemical constituents due to genetic factors. Thus, selection of superior coffee cultivars requires careful evaluations and characterizations for yield, disease resistance and quality traits under various field management and processing techniques across major coffee producing locations in the country. 2011/07/09 - 13:14