Genetic variability, heritability, genetic advance and phylogenetic relationship between rice tungro virus resistant and susceptible genotypes revealed by morphological traits and SSR markers

A study was conducted to assess the resistant sources, genetic variability and phylogenetic relationship among 44 rice genotypes based on pathogenicity, genetic parameters of morphological traits and simple sequence repeat markers. Results demonstrated that, 9 genotypes were resistant, 9 were moderately resistant and the rest of the genotypes were susceptible. The higher level of phenotypic coefficients of variation and genotypic coefficient of variation was found for number of tillers hill⁻¹, number of panicle hill⁻¹, number of filled grain panicle⁻¹, number of unfilled grain panicle⁻¹, total number of spikelets and yield hill⁻¹. High heritability along with high genetic advance was observed for yield hill⁻¹, number of filled grains panicle⁻¹, 1000 grain weight hill–¹ and total number of spikelets panicle⁻¹ and these could be the desirable characters for selection. Polymorphic information content of SSR markers varied from 0.152 (RM161) to 0.760 (RM8213) with a mean value of 0.448. The higher PIC value (0.760) was obtained in RM8213 succeeded by RM3471 (0.719), RM279 (0.716), RM341 (0.689), RM336 (0.665), RM565 (0.664), RM287 (0.601) and RM562 (0.600), respectively which indicated that these markers are effective for the diversity evaluation of current genotypes. Cluster analysis of data matrix of 29 SSR markers, 44 genotypes divided into ten clusters. The results were also supplemented by principal component analysis. Between resistant and susceptible genotypes highest genetic distance was found between IR69705-1-1-1-4-3 and BR11 (0.14), IR69705-1-1-1-4-3 and BRRI dhan71 (0.14) followed by IR71605-3-1-1-2-6 and BRRI dhan49 (0.34), IR71605-3-1-1-2-6 and BR11 (0.38), Matatag 9 and BR11 (0.38), IR81244 (TW-16) and BR11, BRRI dhan39, BRRI dhan48 (0.41), IR71605-3-1-1-2-6 and BRRI dhan71 (0.41), IR81244 (TW-16) and BRRI dhan71 (0.45). Based on genetic distance and disease reaction data susceptible genotypes i.e. BR11, BRRI dhan39, BRRI dhan48 and BRRI dhan71 could be crossed with any of resistant genotypes IR69705-1-1-1-4-2, IR69705-1-1-1-4-3, IR71605-2-1-5-3-4, IR71605-3-1-1-2-6, IR81244 (TW-16), Matatag 9, Utri Merah-16680, Utri Merah-16682 and Utri rajapan to develop tungro resistant variety.