Impact of Climate Changes to Adaptability of Some Rice Germplasm (Oryza sativa L.) Under High Temperature through Quantitative Traits and Simple Sequence Repeats (SSR) Marker

The main objective is to study the effect of heat stress on some quantitative traits of 26 different rice genotypes. The results showed that heat stress caused significantly decreased (p≤0.01) in days to maturity, plant height, flag leaf area, tillers plant-1, panicles plant-1, 1000-grain weight, filled grains panicle-1, sterility %, and grain yield plant-1 traits. Among the 26 cultivars studied, 14 exhibited a high grain yield plant-1. The top-performing genotypes were IR72, IR28, Dular, IR82, and Giza178, with yields of 23.27 g, 22.80 g, 21.60 g, 21.20 g, and 21.17 g, respectively. The reduction in yield compared to the normal growing conditions ranged from 26.87% for Hasswi-2 to 47.89% for Giza178. All traits under study exhibited the highest heritability broadly, with the coefficient of variation (PCV) values surpassing the genotypic coefficients of variability (GCV) in all characteristics. The cluster analysis was divided into two main groups, based on the different types of rice. Using 18 SSR markers was essential in assessing the genetic diversity of rice genotypes. The analyzed markers produced 137 alleles, averaging 7.61 alleles per locus. A greater number of alleles per locus was observed with the primers RM547, RM209, RM219, RM205, and RM234. All SSR markers had high polymorphism information content (PIC) values, averaging 0.3891. PIC values represent allele diversity and frequency among the types. Rice genotypes were split into two groups using cluster analysis. IR31775-30-3-2-2, IR2037-93-1-3-1-1, IR29, IR65829-28-H-P, Dular, PUSA Basmati 1, and WAB 880-1-32-1-2-P1-HB were the seven rice genotypes in the first group. The second group included four rice genotypes (Hasswi-1, Hasswi-2, Giza178, and IET 1444) that belonged to the Indica-Japonica type and were produced from different origins. In any case, the Hasswi-1 and Hasswi-2 came from closely related parents.