Developing rice hybrids for temperate conditions using three line approach

Exploitation of heterosis in the form of hybrid rice is yet to be exploited at commercial level in the temperate regions of India. The present study is attempted to develop rice hybrids for the temperate conditions of Kashmir valley by utilizing the cytoplasmic genetic male sterility system (CGMS). Among the four CMS lines evaluated, the genotype SKUA-7A and SKUA-11A had desirable performances. The 24 test crosses developed involving these CMS lines were evaluated for spikelet fertility and pollen fertility. Moreover, the highest standard heterosis for grain yield and other yield attributes over the check varieties (Jehlum and Shalimar Rice-3) was recorded in the cross combination K15-34 followed by K15-31 and K15-40. Pollen parents of all the three test crosses on screening with RM-6100, DDRMRf3-10 and DRCG-Rf4-14 markers revealed presence of both Rf3 and Rf4 genes responsible for fertility restoration. Besides, 39 genotypes were screened for fertility restoration and the lines RL-2, RL-5, RL-6, RL-7, RL-10, Pusa Sugandh3 and Kohsar were identified to carry homozygous alleles at both Rf3 and Rf4 loci. These genotypes can thus be used as promising restores for the development of temperate rice hybrids.