Effects of Different Nitrogen Levels on uantitative Trait Loci Controlling Yield and Grain Quality in Rice (Oryza sativa L.)
Date Issued
2011
Date
2011
Author(s)
Kao, Shao-Fen
Abstract
Rice yield and grain quality could be directly influenced by different nitrogen levels. In order to reveal the quantitative trait loci (QTL) controlling rice yield and grain quality at different nitrogen levels, a recombinant inbred line (RIL) population consisting of 124 lines derived from a cross from varieties Taichung Sen 10 (TCS-10) and Koshihikari was used as materials. In this study, two nitrogen fertilization levels (80 and 200 kg/ha) were applied and nine traits were evaluated, including yield(Y), plant height(PH), days to heading(HD), chalkiness rate(CR), chalkiness area(CA), chalkiness index(CI), protein content(PC), amylose content(AC) and taste value(TV). The results indicated that significant in yield, PC and TV between two nitrogen levels were observed. Furthermore, PH had significant interaction between line (genotype) and nitrogen level. The effects of nitrogen levels on RILs were mainly based on traits. The correlations between traits were deviated under different nitrogen levels. It implied that expression of some QTL controlling rice yield and quality were probably influenced by different nitrogen levels. According to results of CIM (composite interval mapping) with a linkage map composed of 91 SSR and 2 InDel DNA markers, 16 QTL located on rice chromosomes 1, 5, 6, 8, 10, 11 and 12 were detected at two nitrogen levels. Four QTL including q-PH6, qCR5, q-PC10 and q-TV10 were detected at both nitrogen levels, indicating the expression stability of these QTL. However, QTL q-PH11, q-HD5, q-HD12, q-PC12, q-AC1 and q-TV12 were only detected at low nitrogen level; q-Y8, q-CI5, q-PC5, q-PC11, q-TV5 and q-TV11 were only detected at high nitrogen level. The QTL detected in single nitrogen level are easily affected by nitrogen levels, and it will be resulted in selection and cultivation difference under various nitrogen levels. Moreover, QTL controlling protein content and taste value were detected in the same chromosome regions, showing that difference in taste value between nitrogen levels were mainly caused by the change of protein content. This study not only could provide information for nitrogen fertilization application, but also for maker-assisted selection (MAS) on rice breeding.
Subjects
rice
nitrogen
yield
grain quality
quantitative trait loci
Type
thesis
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