Quantitative Trait Loci for Nonstructural Carbohydrate Accumulation in Leaf Sheaths and Culms of Rice (Oryza sativa L.) and their Effects on Grain Filling.

Abstract

Quantitative trait loci (QTLs) that affect the accumulation of nonstructural carbohydrates (NSCs) in the leaf sheaths and culms of rice (Oryza sativa L.), enhancing subsequent grain filling, were analyzed in a population of back-crossed inbred lines (BCILs) from the cross Sasanishiki (japonica)/Habataki (indica)//Sasanishiki/// Sasanishiki. QTLs affecting NSC accumulation were detected on chromosomes 1, 4, 5, 7, 11 and 12. Of these, the indica alleles of QTLs on chromosomes 7 and 12 increased NSC accumulation, but were detected for only one year in the two-year study. These loci also showed a strong effect on the number of days to heading, suggesting that their effect on NSC accumulation was linked to environmental conditions before heading. The QTLs on chromosomes 1, 4, 5 and 11 did not affect appreciably the number of days to heading. The QTL on chromosome 1 might be identical with the QTL that increases the number of spikelets per panicle in the indica allele, implying that it has pleiotropic effects. The indica allele of this QTL reduced NSC accumulation, which led to an increased percentage of incompletely filled spikelets. In contrast, the indica allele of the QTLs found on chromosomes 5 and 11 increased NSC accumulation and did not affect appreciably the number of spikelets. These indica allele QTLs also exerted some effect on the reduction of the percentage of incompletely filled spikelets, suggesting the possibility that the expression of these QTLs could improve grain filling in rice.

Vrn-D4 is a vernalization gene located on the centromeric region of chromosome 5D in hexaploid wheat

“…The collinear region in rice chromosome 12 includes several Xowering QTLs (Mei et al 2003;Nagata et al 2002;Septiningsih et al 2003;Uga et al 2007). However, it is currently not possible to determine whether Vrn-D4 corresponds to any of these rice QTL, because the arm location of Vrn-D4 in wheat is not yet known, and therefore, the colinear region in rice chromosome 12 is too large.…”

Identification of Quantitative Trait loci and Environmental Interactions for Accumulation and Remobilization of Water-Soluble Carbohydrates in Wheat (Triticum aestivum L.) Stems

“…However, current knowledge of wheat is limited. In other crop species, WSC is a quantitative trait (Galiba et al 1997;Teulat et al 2001;Nagata et al 2002;Takai et al 2005;Thévenot et al 2005). Molecular quantitative genetics is a useful approach for studying complex quantitative traits by describing the characteristics of continuous phenotypic distributions and for estimating the number of loci involved, the average gene action, and the degree of interaction between quantitative trait loci (QTL) and environment (Tanksley 1993).…”

The QTL Analysis of RuBisCO in Flag Leaves and Non-Structural Carbohydrates in Leaf Sheaths of Rice Using Chromosome Segment Substitution Lines and Backcross Progeny F2 Populations

“…Nagata et al (2002) found QTLs for NSC concentration in leaf sheaths and culms on chromosome 5 and 11 but not on chromosome 10 using Sasanishiki/Habataki BILs population. NSC in the culms and leaf sheaths at heading might be controlled mainly by the balance of starch and sucrose metabolism including sucrose transport.…”

“…Previously, QTLs for RuBisCO content (Ishimaru et al, 2001) and NSC concentration (Nagata et al, 2002) have been studied using segregated populations which include epistasis under the complex gene interactions. However, those reports were still far from practical use of QTLs directly toward the development of valuable near isogenic lines (NIL).…”