| Grain filling, as an important feature in rice, directly affects the production. At present, the studiesof grain filling characters such as grain filling rate mainly focused on physiology and biochemistry.However, because the measurement of this trait is complicated, the research using genetic population atthe level of genes is very little. In order to explore the related gene expression during rice grain fillingand obtain stable QTLs with expression in multiple environments, recombinant inbred lines (RIL)population derived from Xieyou9308, which was combined with the molecular genetic linkage map,was used as materials to identify and analyze the QTLs for grain filling rate of superior and inferiorgrains, developmental behaviour of grains, grain filling duration, grain plumpness, grain number perpanicle, number of filled grain per panicle, productive panicles, spikelet fertility, Q enzyme activity,grain length, grain width, grain thickness, grain volume, grain length to width ratio and100-grainweight under different conditions. The main results were as follows:1. The QTLs for the maximum and average grain filling rate of superior grains across fourenvironments (Guiyang2010,2011; Fuyang2010,2011) and inferior grains across two environments(Fuyang2010,2011) were determined using winQTLCart2.5, and13major QTLs were detected onchromosomes1,2,3,4,5,6, and8. A total of5and6QTLs for the maximum and average grain fillingrate of superior grains were detected respectively, and the detected QTL individually accounted for5.12%-9.56%of the phenotypic variation. Among the QTLs, qSGFRmax-4, qSGFRmax-8,qSGFRmean-4and qSGFRmean-8could be detected under two environments. In addition, a total of4and3QTLs for the maximum and average grain filling rate of inferior grains were detected respectively,and the detected QTL individually accounted for7.46%-14.28%.2. Grain filling rate of superior grains at five stages (6d,12d,18d,24d, and30d after anthesis) andaverage grain filling rate of superior grains (1-6d,7-12d,13-18d,19-24d and25-30d) across fourenvironments were used for QTL analysis. A total of21major QTLs were detected on chromosomes1,2,3,4,5,6,7,8,9and11. The detected QTL individually accounted for5.05%-18.09%of thephenotypic variation. Among the QTLs,14and13QTLs for grain filling rate at five stages and averagegrain filling rate at five stages were detected respectively, and6common QTLs were found. qSGFR-3-1could be detected at multiple stages under three environments, and phenotypic variance explained byindividual QTL ranged from7.16%to18.09%. The maximum LOD value was5.64and positive allelecame from Xieqingzao B. A total of major14and11QTLs for grain filling rate of inferior grains at fivestages and average grain filling rate of inferior grains across two environments were detectedrespectively, and7common QTLs were found. Among these QTLs, qSGFR-3-1in the intervalRM136-RM6302on chromosome6could be detected at the same stages in the two trials. Furthermore,it could be detected at four stages in Fuyang at2011, and phenotypic variance explained by individualQTL ranged from6.91%to14.69%. QTLs for grain filling rate of superior and inferior grains weredetected in intervals including RM282-RM6283and RM7370-RM16on chromosome3, RM136-RM6302and RM3724-RM3330on chromosome6, and RM5436-RM3670on chromosome7.3. Developmental behaviour of grains at five stages across four environments was used for QTLanalysis by using conditional composite interval mapping method. A total of21unconditional andconditional QTLs for superior grain weight were detected on chromosomes1,2,3,4,6,7,8and9,explaining5.25%-18.86%of phenotypic variation. Among these QTLs, there were16unconditionalQTLs,11conditional QTLs, and6corresponding QTLs. A total of16unconditional and conditionalQTLs for inferior grain weight at five stages across two environments were detected on chromosomes1,2,3,5,6,7,8and10, explaining5.73%-18.05%of phenotypic variation. Among these QTLs, therewere12unconditional QTLs,10conditional QTLs, and6corresponding QTLs. qIWG-6-1in theinterval RM136-RM6302on chromosome6was detected at four inferior grain filling stages, and therewas corresponding conditional QTL, suggesting that this QTL may play an important role in inferiorgrain filling. QTLs for grain filling rate of superior and inferior grains and grain weight were detected inintervals including RM282-RM6283and RM7370-RM16on chromosome3, RM136-RM6302andRM5436-RM3670on chromosome7, which was consistent with the fact that grain filling rate shows asignificantly positive correlation with grain weight. The results may provide four important intervals forfurther study on grain filling.4. A total of59major QTLs for nine traits including GPA, GPB, GPC, GPD, NFGP, SF, PP, and100-GW across four environments were detected on chromosomes1,2,3,5,6,7,8,9,10and11. TheQTL individually accounted for4.69%-23.74%of the phenotypic variation. A total of2,5,5,6,12,11,6,8and4QTLs for GPA, GPB, GPC, GPD, NFGP, SF, PP, and100-GW were detected respectively.Among these QTLs, qGPC-1, qGFD-6-1, qGFD-7-1, qGFD-7-2, qNFGP-6-1, qGNPP-2, qGNPP-3-1,qGNPP-7-2, qPP-2, qPP-3-1, qWG-3-1, and qWG-6-2were detected across two or more environments.5. Q enzyme activities at two grain filling stages (10d and15d after anthesis) in2010and at threegrain filling stages (10d,15d, and20d after anthesis) in2011in Fuyang were used for QTL analysis. Atotal of9major QTLs were detected on chromosomes2,3,5,6, and7, explaining5.68%-11.59%ofphenotypic variation. There were7,2, and1QTLs for Q enzyme activity at10d,15d and20d afteranthesis, respectively. Both qQ10-3for Q enzyme activity at10d after anthesis and qQ15-3-2for Qenzyme activity at15d after anthesis were located in the interval RM282-RM6283on chromosome3.The QTL for grain filling rate was also detected in this interval, suggesting that Q enzyme activityshows positive correlation with grain filling rate.6. A total of26major QTLs for five traits including grain length, grain width, grain thickness, grainvolume and grain length to width ratio across three environments (Fuyang2010,2011; Guiyang2011)were detected. Among these QTLs,4QTLs for grain length were detected on chromosome3,7,10, and11, explaining3.98%-54.58%of phenotypic variation. qGl3-1in the interval RM6283-RM7370onchromosome3could be detected in the three trials.4QTLs for grain width were detected onchromosome3and6, explaining6.98%-9.77%of phenotypic variation. qGw3-2in the intervalRM7370-RM16on chromosome3could be detected in the three trials.8QTLs for grain thickness weredetected on chromosome1,2,3,6,8,11, and12, explaining4.91%-11.92%of phenotypic variation. qGt3-1could be detected in the trials in Guiyang at2011and in Fuyang at2010.5QTLs for grainvolume were detected on chromosome3,4,6,7, and11, explaining5.07%-22.35%of phenotypicvariation. qGv3-1in the interval RM6283-RM7370on chromosome3could be detected in the threetrials.5QTLs for grain length to width ratio were detected on chromosome3,10, and11, explaining5.17%-47.81%of phenotypic variation. qGlwr3-1in the interval RM6283-RM7370on chromosome3could be detected in the three trials. The maximum phenotypic variance explained by this QTL wasmore than30%. QTLs for grain length, grain thickness, grain volume and grain length to width ratiocould be detected in the interval RM6283-RM7370on chromosome3, and the phenotypic varianceexplained by individual QTL was large.7. QTLs for traits related to grain filling rate under different conditions were analyzed by MCIMusing QTL-Network2.0. A total of24QTL pairs with additive×additive epistatic effects for8traits(the maximum grain filling rate and grain weight of superior grains, grain weight and grain filling rateof inferior grains, grain filling duration, grain width, grain thickness and grain length to width ratio)were detected, explaining0.26%-4.16%of phenotypic variation. QTL×environment interaction effectsof the major QTLs were less than their additive effect.8. Many QTL aggregation intervals were determined in this study, which affected grain filling rate,grain weight, grain type and Q enzyme activity. The results illustrated the close relationship between thefilling rate and yield related traits. For example, QTLs for the maximum grain filling rate of superiorand inferior grains, average grain filling rate, grain filling rate and grain weight at each stage of superiorand inferior grains, grain type, and Q enzyme activity were detected in the interval RM282-RM16onchromosome3; QTLs for grain filling rate and grain weight at each stage of superior and inferior grains,Q enzyme activity, grain plumpness, and number of filled grain per panicle were detected in the intervalRM136-RM6302on chromosome6; QTLs for grain filling rate and grain weight at each stage ofsuperior and inferior grains, Q enzyme activity, number of filled grain per panicle, grain number perpanicle, productive panicles were detected in the interval RM5436-RM3670on chromosome7. |
PDF Full Text Request