Assessment of Genetic Biodiversity of Several Traits Using SSR Markers in Rice (Oryza sativa L.)

Eight primers (RM 315, RM 318, RM 166, RM 302, RM 201, RM 234, RM 526 and RM 144) revealed different levels of polymorphism to tag the related traits of interest as tolerant to abiotic stress, resistant to biotic stress and yield-related traits. Two primers (RM 190 and RM 278) were monomorphic. The percentage of the polymorphism was nearly 80 %. The size of detected fragments ranged from 105–325 bp. A total of 186 bands were scored from the amplification products with the ten SSR primers. Genetic diversity analyses were conducted on the basis of the scores with 176 unique bands. Phylogenic tree for the fifteen rice accessions from each group were established according to the molecular data and based on ten SSRs. A marked genetic diversity was observed in these innovative accessions (Sakha 101, IR 03N137, IR 83142-12, IR 87856-10-AJY-1-B, HHZ 12-Y4-DT1-Y2 and IR 1552), which revealed higher levels of diversity and hence can be used as donors for the effective conservation, utilization and providing favorable genes in rice breeding programs

Evaluation of Inbred Lines of Maize in a Diallel Cross under Normal Condition and Drought Stress

In this study, we examined eight white inbred lines of maize and their F1 crosses under normal and drought stress conditions to estimate their combining ability for grain yield and associated traits. The results showed significant correlation (mean squares) of irrigation treatment with the studied traits. The effects of parents, crosses, and genotypes were all determined to be highly significant under both irrigation levels. Grain yield and other traits showed significant differences (mean squares) associated with both General combining ability (GCA) and Specific combining ability (SCA) under both irrigation regimes, demonstrating the importance of both additive and nonadditive genetic effects in the expression of performance traits. The parental line (P-86) had positive and highly significant GCA effects, as well as the crosses (P-17×P-96), (P-8×P-96), (P-8×P-171), (P-24×P-86), (P-86×P-96), (P-86×P-171), and (P-96×P-171) which then gave the highest specific combinations under both irrigation regimes for grain yield and some of the associated traits. The highest level of heterosis (heterobeltiosis) for grain yield was obtained in the crosses (P-8×P-96), (P-8×P-137), (P-8×P-171), (P-96×P137), and (P-96×P-171) under both irrigation regimes