Identification of Suitable Parents for Production of Hybrid Rice Varieties through Evaluation of Combining Ability and Heterosis

Rice is staple food in Iran. As regards to population increase it is necessary to increase rice yield. Exploration from heterosis is an option for yield enhancement in rice. Selection of suitable parents is the most important step in every breeding programs especially in hybrid rice production. This study was performed with the aim of identifying suitable parents for breeding programs and promising hybrids for experimental hybrid rice seed production at Sari Agricultural Sciences and Natural Resources University. For this propose 5 fertility restoring lines and 5 cytoplasmic male sterility testers were crossed with each other to produce 25 F1 hybrids in 2011 using line × tester method. In the next year, hybrids seeds along with their parents were planted in a randomized complete block design. Seven quantitative traits measured during the growing season and then analyzed. Results showed significant differences among genotypes for all studied traits (P≤ 1%). Sum of squares of genotypes was fractioned to sum of squares of parents, parents vs. crosses and crosses. Results showed that tester T1 and lines L1, 2 and L3 were identified as the best parents according to the high mean performance and good GCA effects for yield improvement. In addition, among the F1s, hybrids L3×T1, L3×T2, L1×T2, L1×T5 and L5×T5 were the promising hybrids for yield according to the mean performance, SCA effects and heterosis values.