QTL Scanning Of Rice Panicle Traits And Fine Mapping Of QPL-3

Rice plays a pivotal role in our country’s food security.It is always an important goal for Chinese scientists to increase of rice yield.The yield of rice is determined by three main factors:panicle number per unit area,grain number per panicle and 1000-grain weight.Rice panicle characters are complex and closely related to yield per plant,including many subcharacters,such as panicle length,number of grains per panicle,1000-grain weight,number of primary branches and stems,number of secondary branches and grain type(grain length,grain width).In-depth analysis of the genetic control mechanism of panicle traits can lay a solid theoretical basis and available gene resources for high yield breeding of rice.Based on the previous work,a set of indica-japonica cross-derived chromosome single segment replacement lines(Sasanishiki/Habataki)were used to conduct QTL scanning for major panicle traits(panicle length,grain number per panicle,number of branches,grain length,grain width and grain weight).One of the QTLs,qPL-3,which controls spike length,was fine mapped.The main results are as follows:1.The panicle traits of CSSL populations derived from japonica Sasanishiki and indica Habataki were investigated,and 11 QTLs related to panicle agronomic traits such as panicle length,grain number per panicle,number of branches,grain length and 1000-grain weight were obtained by scanning QTL IciMapping 3.5 software.The additive effect of 10 QTLs was negative.2.A genome fragment of Habataki was inserted into the end of chromosome 3 of the substitution line SL411,which contained five panicle trait related QTLs,namely qKGW-3,qSPP-3,qBN-3,qGL-3 and qPL-3,indicating that the substitution fragment was a key part of panicle trait variation.Agronomic traits showed that the panicle length and grain length of SL411 were significantly shortened,and the number of grains per panicle and the number of branches at one time were also significantly decreased.3.qPL-3 was initially positioned between markers 3-L12 and 3-L25 by backcrossing the parent Sasanishiki with the surrogate line SL411 as the donor and constructing a locus population by self-crossing,with the size of about 350 Kb.The location population was further expanded,markers were added,individual plants were screened,and progeny test was combined,and finally the fine location was within the range of about 92 Kb between the marker 401 and 407.There were 14 candidate genes in this region.4.The panicle traits of P5 and P8,which only had genotypic changes in the target segment,were investigated.The results showed that qPL-3 alleles of indica reduced panicle length,panicle number and primary branch number.