Detection of stable QtLs for grain protein content in rice (Oryza sativa L.) employing high throughput phenotyping and genotyping platforms

Abstract

Lack of appropriate donors, non-utilization of high throughput phenotyping and genotyping platforms with high genotype × environment interaction restrained identifcation of robust QTLs for grain protein content (GPC) in rice. In the present investigation a BC3F4 mapping population was developed using grain protein donor, ARC10075 and high-yielding cultivar Naveen and 190 lines were genotyped using 40K Afmetrix custom SNP array with the objective to identify stable QTLs for protein content. Three of the identifed QTLs, one for GPC (qGPC1.1) and the other two for single grain protein content (qSGPC2.1, qSGPC7.1) were stable over the environments explaining 13%, 14% and 7.8% of the phenotypic variances, respectively. Stability and repeatability of these additive QTLs were supported by the synergistic additive efects of multi-environmental-QTLs. One epistatic-QTL, independent of the main efect QTL was detected over the environment for SGPC. A few functional genes governing seed storage protein were hypothesised inside these identifed QTLs. The qGPC1.1 was validated by NIR Spectroscopy-based high throughput phenotyping in BC3F5 population. Higher glutelin content was estimated in high-protein lines with the introgression of qGPC1.1 in telomeric region of short arm of chromosome 1. This was supported by the postulation of probable candidate gene inside this QTL region encoding glutelin family proteins.