Combining ability, heterosis and inbreeding depression for quantitative traits in rice

摘要

A study was conducted at Ambasamudram with 28 rice hybrids derived from four early (105-115 days)-maturing varieties as lines and seven extra-early (70-90 days) varieties as testers. Importance of both additive and non-additive gene action was observed for yield and its component traits. However, predominance of non-additive gene was observed for yield and its component traits except plant height. ASD 16 among early parents and Heera and AS 89011 among extra-early parents were identified as the bestcombiners. Further study on selected seven crosses revealed that heterosis over the mid and better parent was negative for days to panicle emergence and positive for panicles plant~(-1), grain yield plant~(-1), dry matter production and harvest index. The superiority of ASD 16 and Heera among parents and ADT 36/Kalyani II, ADT 36/AS 89011 and IR 50/Heera among hybrids was confirmed based on the perse performance and heterosis over better parent in the subsequent season. The inbreeding depression was negative for days to panicle emergence and plant height whereas, residual heterosis was positive for these traits, In contrast, inbreeding depression was positive and residual heterosis was negative for grain yield plant~(-1), dry matter production and harvest index.