Genetic Diversity and Screening of Rice Germplasm Lines against Grain Discoloration Disease

Background: The research was conducted to screen out the diverse rice germplasm lines against grain discoloration disease by using 10 SSR primer pairs and on the basis of various morphological characters to evaluate the diversity of the genotypes at Faculty of Agricultural sciences, University of the Punjab, Lahore. Methods: Seed morphological traits were measured and recorded under Randomized Complete Block Design (RCBD) experiment. DNA extraction and PCR analysis was done to measure the genotypic characteristics of rice. Genotypic and phenotypic variability was measured by using ANOVA and correlation. Microsatellite markers, also called simple sequence repeats (SSR) were used for screening and to check the genetic diversity of rice. Results: The PIC values ranged from 0.204 of RM-07 to 0.640 of primer RM-22 along with other genetic characters i.e., number of alleles, percentage of polymorphism chromosomal location etc. The higher PIC (polymorphism information content) value showed the greatest genetic diversity among the genotypes. The polymorphic SSRs produced 3-5 alleles with an average unit of 3.3. The PIC values ranged from 0.204 to 0.640 with an average mean of 0.51. All the genotypes showed significant differences in all the studied traits which gave the significant results and non-significant results at significance level of p<0.05= *; p<0.01=** respectively. A significant association was also observed between seed length with length width ratio, 1000 grain weight (r= 0.1251*; r= 0.1922**) and seed thickness with 1000 grain weight (r=0.1205*). All these traits showed higher variations for different rice lines. Conclusions: From the study it was concluded that some rice found to be highly resistant (Blue Nile, IR 50, Line 9 (4x15) and Line 12 (4x23) against grain discoloration that could be more useful for the production new rice lines with diverse genetic characteristics.