Department of Agricultural Botany, Agricultural College and Research Institute, Madurai-625 104, India.
*Present address: National Pulses Research Centre (TNAU), Vamban Colony, Pudukkottai-622 303, India.
The two line system of heterosis breeding (S x R) in rice is a new approach for further increasing crop yields. An attempt was made to identify heterotic combinations among the 24 hybrids obtained by crossing four ‘S’ lines, viz., TS6, TS16, TS18 and TS29 with six non-TGMS lines MDU5, IR20, CO43, CO45, ADT39 and Ponni. The three line hybrid CORH2 was taken as the standard check to estimate standard heterosis. The spikelet fertility is an important trait affecting the yield in hybrid rice breeding for which more than 50 percent of the hybrids showed significant standard heterosis. The hybrid TS29 x Ponni recorded the maximum standard heterosis (51.65 percent) followed by TS6 x Ponni (37.7 per cent) TS29 x CO45 (32.00 per cent) and TS16 x CO43 (23.06 per cent) for single plant yield. These hybrids recorded >10% heterosis over the three line hybrid CORH2 and hence they can be utilized in developing high yielding two line rice hybrids.
