Genetic Diversity study in Sorghum (Sorghum bicolor (L.) Monench) Germplasm Accessions Collected from the Major Drought-prone areas of Ethiopia Based on Quantitative and Qualitative Traits
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Date
2008-07
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Addis Ababa University
Abstract
In Ethiopia, the extent of genetic diversity among sorghum germplasm
collections from drought prone areas has not been well studied. To determine
the extent of genetic diversity among different sorghum genotypes grown in
major moisture stressed areas of Ethiopia, a total of 495 sorghum accessions
were evaluated at two representative moisture stress areas. Thirteen quantitative and six
qualitative traits were used in this study. For the quantitative traits, univariate, bivariate
and multivariate statistical methods were applied to analyse the genetic diversity.
Moreover, the phenotypic diversity between the accessions and regions of origin were
estimated based on the qualitative traits using Shannon-Weaver diversity index (H ).
Analysis of variance revealed significant difference among the accessions for all
quantitative traits. Based on their field performance in moisture stress areas, 95 potential
drought tolerant sorghum accessions were identified for further evaluation. Moreover,
cluster analysis grouped the test accessions into eight clusters with different genetic
distance between each cluster. Maximum genetic distances were obtained between
clusters C7 & C8, C4 & C8, and C6 & C7 with D2 190.78, 160.95 and 147.98, respectively.
In principal component analysis, the first four principal components explained 62.09%
of the total variation, indicating existence of high genetic diversity among the accessions.
Furthermore, all the qualitative characters showed high diversity in their distribution as
well as in the amount of variation. The overall average phenotypic diversity (H) among
accessions was 0.82, varying from 0.66 for inflorescence exertion to 0.93 for grain color.
The partitioning of the phenotypic diversity into within and between regions of origins
indicated that 87 % of the total variation was within regions of origin, while only 13%
was found between regions of origin. Therefore, this study confirms the existence of
very high genetic diversity in sorghum germplasm accessions grown in the drought
prone areas of Ethiopia, providing a great opportunity to isolate a number of promising
parents with good traits related to drought tolerance, for crossing to develop drought
tolerant/resistant sorghum varieties.
Key words: Sorghum, Genetic diversity, Drought, Ethiopia, Quantitative
traits, Qualitative traits
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Keywords
Sorghum, Genetic diversity, Drought, Ethiopia,, Quantitative traits, Qualitative traits