QTL MAPPING FOR GRAIN APPEARANCE QUALITY TRAITS USING DOUBLED HAPLOID POPULATION OF RICE UNDER DIFFERENT ENVIRONMENTS

Grain quality is an intrigue attribute with great importance as yield to any rice breeding program. In this study, quantitative trait loci (QTLs) analysis was performed for rice grain appearance quality traits, a double haploid (DH) population derived from Zhongjiazao 17, a super rice variety, crossed with tropic Japonica variety D50. The seven appearance quality traits of DH population grown under three different environmental conditions were measured based on a linkage map containing 170 SSR markers. Total of 73 QTLs were identified covering all chromosome except chromosome 12. The main focus of the study was to identify QTLs that were stable under all different environments. However, four QTLs including GL3, GW3, LWR3 and TGW3 found in the surrounding of pericentromeric region of chromosomes 3. These QTLs, found responsible for grain length and grain width. GL3, a major gene with qGS3 was repeated in all three growth conditions, particularly interval RM6929-RM15490 was detected and stable in all three environments with phenotypic variations of 34.97%, 21.32% and 33.0%. In addition, for digenic interaction, a total of 8 QTLs on five traits were identified for additive environment interaction. Conclusively, QTLs qPGC-1, qTGW-3 and qCS-1 had high phenotypic variation and additive effect that could improve the Grain appearance quality and such findings are valuable for future map -based cloning of the new detected QTLs and improving grain appearance quality and yield.

Automated summary

In this study, QTL analysis was performed to identify stable genes related to rice grain appearance quality. GL3, GW3, LWR3 and TGW3 were found to be responsible for grain length and grain width. Additionally, 8 QTLs related to additive environment interaction were identified. These findings are valuable for future map-based cloning and improvement of grain appearance quality and yield.