SRINIVAS, THRUDAYA RAJ, K2020-03-042020-03-042019http://krishikosh.egranth.ac.in/handle/1/5810144185D5956The present investigation was carried out to evaluate and characterize 80 rice genotypes for seedling and reproductive salinity tolerance and also to study character association for reproductive salinity tolerance parameters, namely, grain yield and yield components and salinity score at seedling stage under saline conditions. The investigation was undertaken at Regional Agricultural Research Station, Maruteru during kharif 2016. The analysis of variance revealed significant differences among the genotypes for all characters studied. Phenotyping of the genotypes for reproductive and seedling salinity tolerance revealed the superiority of Nonabokra and Pokkali. Hence, these genotypes are identified as promising salinity tolerant lines with both seedling and reproductive salinity tolerance. The results on character associations between reproductive salinity tolerance parameters, namely, grain yield and yield components and seedling salinity scores revealed positive and significant association of grain yield with panicle length, number of filled grains per panicle, ear bearing tillers per plant and 100-seed weight under saline conditions. The study of 80 genotypes for their molecular diversity with 14 SSR markers revealed that banding pattern of MCM-41, MCM-48, MCM-100, MCM-223, MLT-5, MLT- 7, MTU-1064, MTU-2077, MTU-3626, MTU-1078, MTU-1153, MTU-1156, FL-478 was analogous to Pokkali (wild donor) and Nonabokara (salinity tolerant variety) at 180bp with RM10793on chromosome 1. The genotypes, MCM-41, FL-478, CST-9, MTU-1078, Pokkali and Nonabokra showed similar amplicon size of 210 bp and were distinct from banding pattern of remaining genotypes with the SSR marker, RM10964. xiii Among the markers used for study of diversity, marker RM 10793 reported highest PIC value of 0.838 followed by RM 10694 (0.763), RM 20224 (0.637) and RM 518 (0.603). RM 10793 showed maximum number of four alleles along with RM 10694 (4) followed by RM 20224 (3), RM 492 (3). Cluster analysis and dendrogram for the 80 genotypes by UPGMA (Unweighted Pair Group Method with Arithmetic Averages) revealed distribution of the 80 genotypes into two major clusters. Cluster I comprised of three sub clusters, while, Cluster II comprised of two sub clusters. Most of the salt tolerant varieties viz.,Pokkali, Nonabokra, CSR -27 were grouped in sub cluster II B. It is concluded that Pokkali and Nonabokra, genotypes can be used as donor for varietal improvement or for introgression of salinity tolerance into a susceptible variety.en-USnullThesis