[Mapping QTL for rice milling and appearance quality traits in indica rice]

Quantitative trait loci (QTL) controlling six milling and appearance quality traits were analyzed over 2 years using recombinant inbred lines derived from two indica rice Teqing and IRBB. A total of 30 QTL for these traits were detected, of which eight were for brown rice rate (BRR), two for milled rice recovery (MRR), two for head rice recovery (HRR), seven for grain length (GL), five for grain width (GW), and six for length/width ratio (LWR). The QTL were distributed on all chromosomes except for chromosomes 4 and 12. A QTL cluster with major effects on GL, LWR, BRR, and HRR was located in the RM15139-RM15303 interval on chromosome 3, which includes the GS3 gene for grain size. The phenotypic variances explained by the QTL were 59.51%, 36.68%, 19.51%, and 4.56%, respectively. QTL affecting GW, LWR, BRR, and MRR were clustered in the RM437-RM18038 region of chromosome 5,which covers the GW5 gene for grain width, and contributed 59.51%, 36.68%, 19.51%, and 4.56% to the total variance. QTL with minor effects on BRR and MRR were mapped to the RM190-RM587 interval covering the Wx gene for amylase content on chromosome 6. These results suggest that GS3 and GW5 may play a major roles in the genetic control of BRR and grain shape.