Mapping of quantitative trait loci (QTL) for grain length in basmati rice (Oryza sativa L.) using Basmati-370 x Pusa Basmati 1 RIL population

Grain shape of basmati rice is an important quality trait determining consumer acceptance. In the present study, the mapping population comprised of 140 F-7 recombinant inbred lines (RILs). Basmati 370 and Pusa Basmati 1 cross were used for identification and molecular mapping of simple sequence repeat (SSR) markers linked to grain length in basmati rice. The phenotypic data was recorded for various quality and yield contributing traits and for genotyping, 70 polymorphic SSR markers were used. Using both phenotypic and genotypic data, two QTLs linked to grain length were detected on chromosome 4 and 6 corresponding to marker intervals RM13838- RM3698 and RM13840- RM530 respectively. Earlier studies also reported the QTL on chromosome 4, however QTL on chromosome 6 has also been reported. The QTL was identified on the chromosome number 4 with LOD score of 3.23 whereas the other QTL located on the chromosome number 6 with a LOD score of 2.7. Furthermore, the two identified QTLs were designated as qGRL-4. 1 and qGRL-6. 1 which can be further be used in rice breeding programme to enhance the grain length particularly in local basmati rice where grain length is very short. Moreover, these QTLs can also be used for the development of good genetic stock to be used in marker assisted backcross breeding. In the study, the identified major QTLs affecting basmati grain length can be used further for fine mapping and validation of specific genes to develop gene based perfect markers for use in rice breeding.