Identification of quantitative trait loci underlying milling quality of rice (Oryza sativa) grains

Abstract

Milling quality of rice grains is important to both producers and consumers. In this study, quantitative trait loci (QTLs) controlling brown rice rate (BR), milled rice recovery (MR) and head rice recovery (HR) were analysed by composite interval mapping over 2 years using 98 backcross inbred lines (BILs). A total of 12 QTLs for the three traits were detected, of which five were for BR, four for MR and three for HR. The proportion of phenotypic variation explained by individual QTLs ranged from 7.5 to 19.9%, and additive effects contributed by a single QTL accounted for 0.46 to 2.34% of the variation. QTL-byenvironment interactions were observed by comparing QTL mapping of the same population grown in two consecutive years. Three of five QTLs for BR and two of four QTLs for MR were detected in 2 years, and all three QTLs for HR were detected in 1 year only. BR was significantly correlated with MR, and all four QTLs of MR were located in the same regions as those of BR. This indicated that QTLs for highly correlated traits could often be detected in the same interval.

Detection of Quantitative Trait Loci for White-back and Basal-white Kernels under High Temperature Stress in japonica Rice Varieties

“…Therefore, this QTL is likely to exert a minor effect on the apparent quality of brown rice, or it may act only under low temperature conditions (this QTL would not be effective under high temperature conditions such as those in 2004). Li et al (2003) also reported the presence of a QTL associated with chalkiness of the endosperm on chromosome 3. Due to the lack of common DNA marker shared in their and our studies, it is not possible to determine the allelism of these QTLs.…”

“…This trait is considerably affected by genes and also by the environment, especially high temperature immediately after heading. Li et al (2003) reported the presence of a QTL associated with chalkiness of the endosperm on the short arm of chromosome 6 using an F 2 population derived from the cross Nipponbare (japonica)/Kasalath (indica)//Nipponbare. Xu et al (2000) also reported the presence of a QTL associated with chalkiness of the endosperm and the percentage of occurrence of white-core on the short arm of chromosome 6, using F 2 and F 3 populations and an F 10 recombinant inbred line population from a cross between Zh97 and Ming63, the parents of Shanyou63, the most widely grown indica hybrid rice variety in China.…”

Breeding of a target genotype variety based on identified chalkiness marker-QTL associations in rice (Oryza sativa L.)

“…Grain chalkiness is quantitatively inherited and controlled by effects of polygenes that are greatly modified by environments. Some QTLs associated with chalky grain have been identified (Li et al, 2003;Zhou et al, 2009;Liu et al, 2011;Liu et al, 2012). QTL inheritance was shown to be complex (Shi et al, 2002); therefore, if marker-assisted selection (MAS) strategies are applied for (or against) this trait, it is necessary to identify and mark the major QTL involved in trait determination.…”

Studies on rice seed quality through analysis of a large-scale T-DNA insertion population

“…Along with the growth of economies and population throughout the world, there is an increasing demand for high-yield and high-quality rice. The grain quality of rice, including that of milling, appearance, cooking and eating, and nutrition, is determined by multiple physicochemical properties [2], and studies on the involved key genes and relevant regulatory mechanisms will help to illustrate the regulatory networks of rice quality control and benefit for the breeding efforts.…”

“…Along with the growth of economies and population throughout the world, there is an increasing demand for high-yield and high-quality rice. The grain quality of rice, including that of milling, appearance, cooking and eating, and nutrition, is determined by multiple physicochemical properties [2], and studies on the involved key genes and relevant regulatory mechanisms will help to illustrate the regulatory networks of rice quality control and benefit for the breeding efforts.Starch, which is composed of amylose and amylopectin, comprises ∼90% of dry endosperm of rice seed.The apparent amylose content (AAC) is recognized as an important determinant of the appearance and texture of grain [3]. Thai jasmine rice (KDML 105), one of the best-quality rice with good cooking and eating qualities, has low amylose content (AC) and medium gel consistency (GC) [4].…”