Linkage analysis for QTL associated with panicle number on chromosome 2 in rice (Oryza sativa L.); Toward identification of the regulatory gene

Abstract

A QTL associated with panicle weight of rice was located on chromosome 2 (Obara et al., 2001 JEB 52, 1209-1217). In this case, the Kasalath alleles contributed to increase in the panicle weight. A nearly isogenic line, C-22, is consisted of the substituted small segment from Kasalath chromosome in the target QTL of Koshihikari's genetic background. The C-22 showed significant increases in tiller number at the early vegetative stage, total panicle weight, and panicle number when compared to Koshihikari. Nine substituted lines, in which the 50 cM segment from Kasalath chromosome of C-22 was recombinated, were selected to determine the ratio of developing tiller formation in the 2th axil. Linkage analysis showed that QTL for panicle number was detected between DNA markers, 2-S152 and 2-S173. This region was approximately 10 cM. For further delimitation of QTL region, linkage analysis with recombinant plants between 2-S152 and 2-S173 is now in progress.