Identification of Japonica Chromosome Segments Associated with Heterosis for Yield in Indica x Japonica Rice Hybrids
Bian, J.; Jiang, L.; Liu, L.; Xiao, Y.; Wang, Z.; Zhao, Z.; Zhai, H.; Wan, J.
Crop Science 50(6): 2328-2337
ISSN/ISBN: 0011-183X DOI: 10.2135/cropsci2010.05.0242
To exploit the heterosis for yield and yield-related traits expressed in indica x japonica F(1) hybrids of rice (Oryza sativa L.), a set of 64 chromosome segment substitution lines (CSSLs) was constructed, with each line selected to carry one or a few chromosome segments of the japonica cv. C418 in a genetic background of indica cv. 9311. The CSSLs were crossed one by one with the recipient parent to generate a set of 64 corresponding F(1) hybrids (CSSLHs). These materials were field tested over 2 yr for six yield and yield-related traits. A total of 48 (in 2008) and 55 (in 2009) quantitative trait loci (QTL) were detected, with most individually explaining only a modest proportion of the phenotypic variance. In 2008, 72.9% of the QTL were overdominant, whereas in 2009, this proportion was only 54.5%, indicating that overdominance is important in determining heterosis in japonica x indica rice hybrids, and chromosome segments substitute technology is effective in the utilization of heterosis from intersubspecific cross between indica and japonica rice. Moreover, some of the CSSLs harbored QTL associated with heterosis in both years; these should represent potential candidates as parents of F(1) hybrids along with cv. 9311 or other indica lines.