Linkage analysis for QTL on chromosome 2 which associated with panicle weight in rice (Oryza sativa L.)

Abstract

Our previous QTL and linkage analyses showed that a QTL (Pnw1) associated with panicle weight on the main stem of rice was located in the vicinity of marker C777 on chromosome 2. In this case, the alleles from Kasalath contributed to increases in panicle weight. A nearly isogenic line, C-22, was selected in Koshihikari's genetic background. The C-22 confirmed a small segment (50cM), including Pnw1, which was substituted for Kasalath chromosome. In a green house, the C-22 showed more total panicle weight and more panicle number than Koshihikari, particularly when grown with low-nitrogen supply. A high-density genetic map around Pnw1 was constructed with newly 20 markers using 200 segregates. For further linkage analysis, we selected 177 plants that occurred recombination between marker C777 and C10005 using 3385 segregates. Genotyping of these plants and linkage analysis are now in progress.