Abstract:

Selecting individuals with improved genotype is important in breeding practice, while predicting superior genotype is the basis of selection. An immortalized F₂ population in rice (Oryza sativa L.) derived from F1 hybrid between Zhenshan 97 and Minghui63 was used for QTL mapping on grain weight per panicle (GWP). Based on the results of QTL mapping, the genotypes and genetic effects of superior lines (SL) and superior hybrids (SH) in two different environments were predicted. Results showed that a total of nine QTLs controlling grain weight per panicle were detected in two environments. Epistatic effects were largely contributed to GWP as well as QE interaction effects had an impact on GWP. The genotypes and genetic effects of SL and SH in the two environments were different. The genetic effects of the predicted SH were the highest in the two environments, so SH could fully bring out the great potentialities of GWP. Nearly a half of QTLs of the predicted SHs in two environments were homozygous, which implyed that heterozygotes at all nine loci were not always advantageous for performance. The paper also mainly discussed how to obtain SL and SH in breeding.

Key words: Rice, QTL mapping, Superior genotype, Grain weight per panicle