Inheritance of thermo-sensitive genic male sterility (TGMS) in rice (Oryza sativa L.)

The thermo-sensitive genic male sterility (TGMS) system has great potential for revolutionizing hybrid rice production through simple, less expensive and more efficient seed production technology. For the successful utilization of this novel male sterility system, knowledge of its genetic is essential. In this study, six independent crosses were generated by crossing six elite TGMS lines with six male parents during the 2004-2005 rabi season. These hybrids were raised and selfed during the 2005 kharif season to get F-2 seeds. During the 2005-2006 rabi season, parents, hybrids, and F-2 generations were evaluated for seed set percentage by bagging under sterility-inducing conditions. The plants were classified into two groups- a plant whose seed set was zero as sterile and a plant whose seed set was higher than zero as fertile. The fertile to sterile plants in the F-2 generation of all the crosses fitted well with a 3:1 ratio pointing to the monogenic recessive nature of sterility. The seed set percentage along with morphological characteristics of the anther and pollen grains must be used to ascertain the genetics of the TGMS trait.