Rice, White Rice Protein Content Qtl Fine Positioning Analysis

Rice is one of the most important crops and now also as one of the model organisms for plant molecular biology. It is important and useful for both breeding and biological study to understand the genes function in rice. Because of these important of rice in social life and biological research, the screening for elite germnplasm and researeh on various biological, which include rice grain quality, have never stopped. As we known, protein content in rice endosperm plays an important role in determinging rice grain quality. So genetic studies as a key part of high quality rice breeding is undoubtedly very important.Rice protein content is a typical quantitative trait.So it is difficult for us to analyze and map the quantitative trait loci (QTL) via traditional genetic methods. Chromosome segment substitution Lines (CSSLs) are ideal tools which can used to detect rice protein content QTLs and their genetic analysis, as which has little background noise and does not require complex statistical analysis.Especially, a set of chromosome single segment substitution lines (CSSLs) covered the whole genome can supply genetic materials for the indentification of other usful genes.Using CSSLs derived from Sasanishiki/Habataki cross as material, we determine d the protein content of39lines. The correlated QTLs was analyzed and located. In addition, the fine mapping of QTLs related to protin content was performed based on the preliminary results.The main results were as follows:1.Two lines (SL402、SL403) with low protein content were selected from a set of chromosomal Segment substitution lines, of which each contains a single or few substitution segments of an indica variety Habtaki in the genetic background of japonica variety sasanishiki. The graphical genotype analysis of the lines (SL402、 SL403) by using polymorphic makers revealed that it harbors only one chromosomal segment from the indica with the similar genetic background to sasanishiki. The results suggest that indica substitution segment earring the QTL is one major cause of the low protein content in SL402、SL403.2. The F2and F3segregation populations derived from SL402/Sasanishiki cross were Planted in Yangzhou and Hainan Respectively. The protein content of these segregation populations vary in continuous trend and exhibits the normal distribution.3. Based on the progenies from F2and F3segregation populations derived from SL402/Sasanishiki cross, two protein content QTLs (lpc1, lpc2) were detected, lpc2was restricted in a300-kb region between Z2and Z4via map QTL5.0software analysis.