Inheritance of grain shape and molecular tagging of the QTL for reduced grain width (gw) in rice (Oryza sativa L.)

Abstract

Grain shape as determined by the ratios of grain length (L) to width (W) is an important trait affecting consumer preferences and the rice markets worldwide. Study of its inheritance and identification of linked molecular markers are therefore essential for rice breeding with desirable grain shapes. For this purpose, we used the Single Segment Substitution Lines (3-S Lines) developed by crossing HJX74 (medium grain) with Amol-3 (slender grain) and Basmati 370 (slender grain). Slender shape (L: W > 3) of grain was found to be monogenic recessive. The QTL for grain width (gw8) was mapped to the distal end of the chromosome 8 and was found to be linked with RM447 (0.0cM) and RM502 (2.5cM) which were located at a distance of 55kb on the same clone AP005529 of rice physical map. The study should facilitate map-based cloning of the gene (QTL) and marker-assisted selection (MAS) for slender shape of grain in rice.