Genetic Analysis of Submergence Tolerance Rice Genotypes by Introgression of Sub1 QTL to Indica HYV through Breeding Populations (F2) with Marker Assay

Abstract

More than 2.0 million-hectare area was affected by flash floods of various grades and reduced the average yield in Bangladesh by 5%. It involves introgression of Sub1 QTL into the genetic background of HYV rice through marker-assisted breeding and to evaluate submergence tolerance of high yielding rice varieties. SSR profiling was performed to tag the submergence tolerant QTL by using sub1 flanking markers and F1 confirmation of Binadhan-7 x BRRI dhan52 (F1) by using the primer RM1115. The gene diversity value was 0.7610 and the polymorphism information content (PIC) values were 0.7432 & allele frequencies (%) were 0.3328. Binadhan-7 x BRRI dhan52 (F2) crosses were possessed the highest grain yield plant-1 (38.00 g) which was significantly higher than its both parents and also early maturing as 124 days from all crosses. The genetic similarity analysis using UPGMA (Unweighted Pair-Group Method using the Arithmetic Average) clustering system generated 5 major genetic clusters. Maximum intra-cluster degree of diversity was observed in cluster4 (79.93) and minimum in cluster3 (31.44). Highly significant and positive correlations were found among the grain yield (GY) and Total tillers/plant, effective tillers/plant, panicle length, and filled grains/panicle. The first three principal components with Eigen-values explained 73.7 % of the total variation among 16 rice genotypes for the 9 quantitative traits studied. However, it is hoped that promising Sub1 cross combination Binadhan-7x BRRI dhan52 will be able to develop three to four weeks tolerance with high yielding submergence tolerant varieties to increase rice production in submerged prone areas of Bangladesh where single flash floods occur under different cropping patterns.