Genetic Analysis And Mapping QTL Of Rice Hull Thickness And Related Traits

Rice is an important food crop, is also the monocotyledonous model organisms. Rice hull is an important part of rice floral organ. Brown rice may has close relationship with rice hull, because of its growth under the package if rice hull. So no matter from flower organs side or from the perspective of the development of rice grain, rice hull was important.We conducted a quantitative trait loci (QTL) analysis of165rice recombinant inbred lines (RJLs) super hybrid rice’Xieyou9308’. Chromosomal segment substitution line on the background of XieqingzaoB with inserting zhonghui9308chromosomal segment was used to validate QTL of hull thickness expressed both in HN and HZ. QTL mapping of rice hull thickness and related traits and correlation between rice hull thickness and rice quality was main scheme in this study.Milling quality, appearance quality, cooking and eating quality was a complex trait controlled by multiple genes. Rice quality mainly includes milling quality, exterior quality, cooking and eating quality. Among them, the milling quality, it also includes the brown rice, milled rice and head rice, Exterior quality including length width ratio, endosperm translucency, chalkiness percentage and chalkiness degree. Cooking and eating quality includes gelatinization temperature, gel consistency and amylose content. Rice quality measurement according to the standard of the ministry of agriculture issued with some modification.This research mainly discussed the rice hull thickness and related traits QTL mapping and correlation analysis, rice hull thickness was closely related with the development of rice grain. Grain thickness, brown rice thickness, hull thickness, milling quality, exterior quality, cooking and eating quality was used for QTL mapping in Hainan (HN) and Hangzhou (HZ). Forty-six QTL of hull thickness and related traits were detected with phenotypic effect range from0.44%to48.09%, with LOD from2.97to26.88. Seven QTL were detected repeatedly across two environments, such as qGT3, qBRT3, qLWR3, qBRT4, qHT6.1, qHT8, qHT11. Among all QTLs, three stable expressed QTL, qHT6.1, qHT8and qHT11were detected on chromosome6,8and11controlling the thickness of rice hull. Additionally, the QTL cluster in interval of RM5944-RM5626on chromosome3probably was responsible for grain thickness as well as milling quality. Locating in interval of RM6992-RM6473on chromosome4, the cluster of qBRT4and qGT4also played important roles in grain-filling, probably allelic with GIF1. Three lines(X345, X338and X389) were selected because there were homozygous fragments in genotype of Zhonghui9308 overlapped with hull thicknesss QTL (qHT6.1, qHT8and qHT11). Meanwhile, the hull thickness of XieqingzaoB was thicker than X345, X338and X389. In all, qBT6.1, qHT8and qHT11were stable inheritance with obvious genetic effect and regulated rice hull thickness.Hull thickness was significantly positive correlated with grain thickness, brown rice thickness, but not with milling quality as expected. However, brown rice, milled rice and head rice had a significant correlation between each other. Hull thickness had no significant correlation with exterior quality. Hull thickness was significantly correlated with cooking and eating quality in2011HN, while not in2011HZ. The reason may be that micro environment was different.