Study of Combining Ability of Rice Cytoplasmic Male Sterility (CMS) Lines for Hybrid Seed Production

Heterosis is a solution for yield enhancement in rice. Selection of suitable parents is the most important step in every breeding program. This study was performed with the aim of determination of combining ability of male sterile and fertility restoring rice lines for heterosis evaluation. For this propose, 3 cytoplasmic male sterile testers were crossed with 4 fertility restoring lines using line × tester method. Parents and their F1 progenies arranged in RCB design and ten quantitative traits measured during the growing season. Analysis of variance showed significant differences among genotypes for all studied traits (P≤ 1%). Furthermore, the crosses effect was significant for all traits at 1% level. Results showed that tester Neda A and lines IR50, IR68061 and IR5931 were identified as the good parents based on positive and significant GCA effects for grain yield. Hybrids Neda A × IR68061, Nemat A × IR5931, Neda A × IR50, Nemat A × Pouya and Champa A × Pouya showed high significant effects for days to 50 percent heading. Hybrids Nemat A×IR50, Nemat A×IR68061 and Neda A× IR50 showed the higher mid parent heterosis. Hybrids Neda A×IR50, Neda A×IR68061 and Nemat A×IR50 showed the higher heterobeltiosis. Finally, hybrid Neda A× IR50 with heterosis values of 18.14% (mid parents) and 17.43% (superior parent) identified as the best promising hybrid for hybrid seed production in rice.