Abstract:

Heading date (HD) is an important agronomic trait in rice. Appropriate HD is a prerequisite for attaining the desired yield level in rice breeding programs. Mapping HD quantitative trait loci (QTL) is important for rice improvement. We used 94 chromosome segment substitution lines (CSSL) derived from 9311/Nipponbare with 9311 as the recurrent parent for analysis of QTL controlling HD. By substitution mapping, 4 QTLs were mapped on rice chromosomes 3, 4, 5 and 8 (P≤0.01). The additive effect of the 4 QTL ranged from –6.4 to –2.7, and the additive effect percentages of the 4 QTL ranged from –6.4% to –2.7%. The additive effect of qHD-3 and qHD-8 showed the feature of major genes. To map qHD-3 and qHD-8, 16 pairs of primers were selected from simple sequence repeat primer pairs according to the rice physical map. qHD-3 was located in the interval between RM3166 and RM16206, which was 13.9 cM in genetic distance on rice chromosome 3, and qHD-8 was mapped in the interval between RM4085 and RM8271, which was 6.4 cM in genetic distance on rice chromosome 8. Mapping of QTL has laid a foundation for improving HD with marker-assisted selection in rice.