Abstract

The extent of heterobeltiosis and standard heterosis of ten characters of one hundred and fifteen rice hybrids developed by crossing five CMS lines and 23 testers in line x tester fashion were evaluated under irrigated conditions during kharif, 2008 over three locations viz., Hyderabad, Warangal and Jagtial representing different agro climatic zones in Andhra Pradesh, India. The pooled analysis of variance (line x tester) revealed significant differences among locations and genotypes for all the characters studied. The line x tester interactions contributed up to 71.89 per cent for days to 50% flowering followed by productivity per day (68.54%), grain yield per plant (67.69%) and spikelet fertility per cent (66.02%). The highest percentage of average heterosis was observed for productive tillers per plant followed by productivity per day and grain yield per plant whereas the highest percentage of standard heterosis was observed for filled grains per panicle and flag leaf width. Pooled standard heterosis for grain yield plant -1 was manifested through panicle weight, number of filled grains panicle -1 and productivity day-1 . Negative standard heterosis was observed for days to 50% flowering due to earliness in six hybrids over standard checks KRH 2 and PA 6201. Five crosses viz., APMS 6A x 1005, APMS 6A x GQ-25, PUSA 5A x IR 43, APMS 6A x SC5 9-3 and PUSA 5A x KMR-3 were identified as potential hybrids with more than 28% standard heterosis for grain yield over better yielding commercial hybrid check KRH2. Testing of these hybrids in all India coordinated trials across different states of the country may result in identification of better hybrids in the near future for commercial exploitation.

Keywords: Heterosis, hybrid rice, multilocation testing, yield attributes