Genetic mapping for flag leaf shape in new plant type based recombinant inbred lines in rice (Oryza sativa L.)

The flag leaf, a pivotal element in rice plants’ photosynthesis process, holds great significance in rice breeding initiatives aimed at optimizing plant traits. The dimensions of the flag leaf play a critical role in photosynthesis, thereby exerting a considerable influence on the potential yield of rice. In this study, we utilized an NPT-based mapping population comprising PR126 (a green super rice cultivar) and Pusa NPT34 (a new plant type line) recombinant inbred line (RIL) population consisting of 175 lines, evaluated across three distinct locations. A total of seventeen QTLs were detected for flag leaf length (seven), width (five), and area (four) distributed across chromosomes 2, 3, 4, 5, and 6, observed across different locations. Among these 17 QTLs, 8 were found to colocalize on two genomic regions. Validation of these QTLs was performed using F_2:3 families obtained from the cross between Pusa Basmati 1509 and Pusa NPT34. One marker, RM190, successfully validated the QTLs qFLW6.1 and qFLA6.1 at ADT. Remarkably, both validated QTLs are situated within the same marker interval on chromosome 6 and genetic contribution for both QTLs is from ‘Pusa NPT34’. Consequently, further refinement through fine mapping of the marker intervals holds promise for narrowing down the genomic region and pinpointing candidate genes. This will facilitate more precise marker-assisted selection strategies for enhancing flag leaf shape attributes.