Molecular mapping of QTLs associated with grain elongation in basmati rice Oryza sativa L

Abstract

newline The enhancement of grain qualityis one of the major targets that are focused upon by rice breeders to develop elite rice varieties. Diverseattributes are examinedwhile determining the grain quality in rice which includes aroma, amylose content (AC), gelatinization temperature (GT), volume expansion and specifically, lengthwise grain elongation (GE). Cooked GE is the most desirable feature ofpremium quality rice varieties such as Basmati that is influenced by starch properties. The inheritanceof GE in rice has not been evidently illuminatedbecause of its complex and uncertain pattern. In this study, we identified QTLs for GE in rice using bulked-segregant analysis (BSA) and whole-genome sequencing based on an F2 population segregated from a cross between Basmati 370 and Pusa Basmati 1121 especially for GE characteristic. The QTLs were detected on chromosome 1, 2, 3 and 6 and were found to be located in the close proximity of starch biosynthetic genes such as granule-bound starch synthase I (GBSS I)or Wx, starch synthases (SS), starch branching enzymes (SBE), starch debranching enzymes (DBE), Pullulanase(Pul)andADP-Glc pyrophosphorylase (AGPase). The markers located within the identified candidate genomic regions can be further used for fine mapping and cloning experiments.Furthermore, these identified QTLs can be utilized in rice breeding programs with increased grain elongation to enhance the export potential of Basmati rice.