Phenotype cum genotype evaluation of in vitro mutagenesis-derived lines from traditional rice variety Salumpikit for abiotic stress

Major abiotic stresses viz. salinity, drought, and submergence post a major threat in rice production. In order to mitigate these stresses, several breeding techniques such as In vitro. Mutagenesis has been employed to fast tract the development of stress tolerant rice varieties with improved agronomic characteristics. Success of breeding line development for stress tolerance depends on rigorous screening and evaluation. A total of 52 Salumpikit in vitro mutagenesis-derived mutant lines selected based on improved agronomic traits and the wild type were evaluated for seedling stage salinity, drought, and submergence stress tolerance. Furthermore, the lines were evaluated genetypically using molecular markers ART5 and SC3 (submergence), RM8094, RM6711, RM10794, and RM7075 (salinity) and RM511 (drought). Of the 52 lines evaluated, 11 (21.15%) were identified as tolerant lines to submergence, 12 (71.2%) lines including the wild type for salinity and 9 (16.98%) lines as moderately tolerant to tolerant to drought through seedling stage phenotypic evaluation. Genotypically, 49 (88.46%) lines including the wild type were validated for presence of sub 1 gene in SC3 primer, 45 (86.54%) for SalTol QTL in 4 SSR markers and 44 (84.62) lines including the wild type for qDTY 12.1 in RM511. Considering combined phenotypic and genotypic evaluation, 4 lines viz. PR45713-Salumpikit-IVM2011WS 1-3-18, PR45713-Salumpikit-IVM2011WS 1-4-9, PR45713-Salumpikit-IVM2011WS 1-4-9, PR45713-Salumpikit-IVM2011WS 1-4-7 and PR45713-Salumpikit-IVM2011WS 1-9-10 were identified to have multi-stress tolerance. Furthermore, these identified lines showed higher stress tolerance in comparison with the wild type. Thus, the study showed the effectiveness of in vitro mutagenesis, through combined tissue culture and gamma irradiation in enhancing genetic variability and development of improved lines with tolerance to both major abiotic stresses (salinity, drought, and submergence). Furthermore, utilization of combined phenotypic and genotypic evaluation increases precision in multi-stress tolerant line selection.