Abstract:

A chromosome segment substitution lines population, derived from Asominori/IR24 with Asominori as the recurrent parent, was planted and phenotyped for amylose content (AC) and protein content (PC) of milled rice in two successive years and four sites. QTL for AC and PC were characterized and stability of their expression was investigated. The phenotypic value for AC and PC showed a continuous distribution and some transgressive lines were also observed. Additionally, a total of 8 QTL for two quality traits were identified, and two of them were consistently detected in the eight different environments. Phenotypic values were different significantly (P<0.01) between Asominori and the CSSLs harboring any of the two QTL alleles. Otherwise， the significant QTL by environment interactions were observed for qAC-8 and qPC-8 in two of the eight environments. Therefore, these results indicated that the two QTL, qAC-8 for AC and qPC-8 for PC, were stably expressed in different environments. Since QTL qAC-8 and qPC-8 were both mapped in the G1149–R727 interval, the two RFLP markers, namely G1149 and R727, would be useful markers for further fine mapping of QTL and marker-assisted selection (MAS) through marker conversion in rice quality improvement.

Key words: Rice (Oryza sativa L.), Amylose content, Protein content, Chromosome Segment Substitution Lines (CSSLs), QTL expression stability, Marker-assisted selection (MAS)