Abstract:

Substitution lines are powerful tools for detecting and precisely mapping quantitative trait loci (QTL) in rice. This research involved use of the indica recipient 9311 as the parent and 132 simple sequence repeat markers with polymorphism between parents. We analyzed agronomy traits and substituted segments of 5 advanced backcross substitution lines derived from a backcross of 9311 and a japonica donor, Nipponbare. Compared with 9311, the 5 substitution lines showed statistically significant differences in grain length, grain width, flag leaf length, plant height and seed shattering. The substitution lines had 8 substituted segments, and the total genetic length of the substituted segments was 236.0 cM, mean 29.5 cM. For the recipient 9311 and substitution lines, 7 QTLs (2 for 1 000-grain weight, 1 grain length, 1 grain width, 1 flag leaf length, 1 plant height and 1 seed shattering) on substituted segments distributed on rice chromosomes 1, 3, 5, 6 and 10 were compared by Student t test. The qFll-1 on chromosome 1 controlling flag leaf length and the qPh-6 on chromosome 6 controlling plant height are novel QTL. The results enhanced the quantitative and qualitative knowledge of substitution lines. Identification of the QTL has laid a foundation for fine-mapping QTL and molecular marker-assisted selection for appearance in rice.

Key words: rice, simple sequence repeat marker, substitution line, substituted segment