Vol. 11, Issue 6 (2022)

Author(s):
V Nagamani, N Shivakumar and TE Nagaraja

Abstract:
Commercial exploitation of heterosis in rice has been made possible by the use of cytoplasmic genetic male sterility and fertility restoration system. Development of red kernel hybrids for micro-nutrient rich food requires potential restorers which are adapted to particular situation. Conventionally, the process of screening for the trait of fertility restoration is by tedious testcross progeny evaluation. In this study, earlier reported SSR marker RM6100 targeting Rf4 gene and candidate gene- based functional markers, RMS-PPR9-1 targeting to Rf4 gene and RMS-SF21-5 targeting to Rf3 gene have been utilized to screen red kernel rice genotypes. Twenty-four, fifteen, and fourteen genotypes were identified as restorers, respectively, based on molecular screening results of RM6100, RMS-PPR9-1, and RMS-SF21-5 markers. Among these, a set of eleven restorer lines with various Rf3 and Rf4 combinations were selected and utilized to produce testcross progenies in combination with WA-based CMS lines, and their fertility restoration was assessed using pollen and spikelet fertility. The pollen parent MSN-15-15 and NSN-1-298 yielded testcross progenies with highest pollen fertility being 100% each, amongst all crosses attempted using CMS lines KCMS 57A and KCMS 53A as the female parents respectively. The spikelet fertility of the test cross progenies involving CMS lines KCMS 59 A and KCMS 59 A was found maximum in combination with pollen parent MO-21 (96.98%) and MSN-10-3 (94.70%) respectively. The red rice genotypes, MSN-10-3 and MSN-15-15 were classified as effective restorers for all the nine CMS lines used and these lines can be utilized in hybrid red rice breeding as potential restorers.