QTL Mapping Of Maize Rapid Chlorophyll Fluorescence Parameters And Yield-related Traits

Photosynthesis is one of the most important factors in determining crop yields.Over 90%of the dry matter products in crops are derived from photosynthesis.Therefore,the efficiency of photosynthesis is directly related to the crop yield.Rapid chlorophyll fluorescence parameters can sensitively reflect the electron transfer efficiency in photosynthesis.It is very important to locate QTLs related to rapid chlorophyll fluorescence parameters and yield traits to cultivate high-efficiency and high-yield corn.In this study,backcross recombinant inbred line population(BIL)and recombinant inbred line population(RIL)were used as research materials.Based on the construction of genetic maps,the rapid chlorophyll fluorescence parameters of maize(ABS/CSo,TRo/CSo,ETo/CSo,DIo/CSo,RC/CSo,ETo/TRo,PIcs)and yield traits(yield per plant,hundred kernel weight,number of grains per row,number of rows per ear)QTL related to fluorescence parameters and yield.The main research results of this article are as follows:1.A combination of maize inbred lines RA and Zheng 58 was used to obtain 163 BILs.A genetic linkage map consisting of 1483 molecular markers with a total genetic distance of 2595.45cM and an average genetic distance of 1.75cM was constructed.Generation 160 RILs,a genetic linkage map consisting of 2915 bins with a total genetic distance of 1896.42cM and an average genetic distance of 0.66cM was constructed2.QTL localization of seven fast chlorophyll fluorescence parameters of the BIL population in a three-year five-point environment,and a total of 78 related QTLs were located,of which QTL-qTC9-2 controlling TRo/CSo was stably expressed in E2 and E3;QTL mapping of the BLUP predicted value about rapid chlorophyll fluorescence parameters,a total of 9 related QTLs were distributed on chromosomes 1,2,4,5 and 7 with LOD values of 2.60-4.91,interpretable genetics the variation is 5.95%-11.00%.QTL localization of seven rapid chlorophyll fluorescence parameters about the RIL population in a four-point environment of three years,a total of 76 related QTLs were located,QTL-qEC3-1 controls ETo/CSo is stably expressed in El and E4.QTL-qET3-1 controls ETo/TRo,QTL-qRC5-1 controls RC/CSo are stably expressed in E3 and E5;Predicted value of the BLUP about rapid chlorophyll fluorescence parameters is located in 26 related QTLs,distributed on chromosome 2,3,4,5,7.The LOD value is 2.52-7.35.and the interpretable genetic variation is 4.56%-14.81%.Both populations have QTL clusters on chromosome 4,and the physical locations corresponding to QTL clusters overlap.Epistatic detection was performed on the rapid chlorophyll fluorescence parameters of the two populations.Two pairs of epistatic QTLs were detected in the BIL population,and no epistatic QTLs were detected in the RIL population.3.QTL mapping of four yield characters of two populations by two environments data and predicted value of BLUP.The BIL population was mapped to a total of 18 related QTLs with LOD values of 2.51-6.55,and an interpretable genetic variation of 6.27%-21.40%,of which QTL-qBHKW3-1 related to 100-kernel weight is stably expressed in the environment,and qBHKW5-1 overlaps with QTL-qBPI5-1 related to the localized fast chlorophyll fluorescence parameter PIcs.The yield-related traits of the RIL population were mapped to 26 related QTLs with LOD values of 2.54-5.37,and the interpretable genetic variation was 6.22%-13.51%.Among them,the 100-grain weight-related QTL-qRHKW4-1 was stably expressed in the environment and was associated with rapid chlorophyll fluorescence The parameters overlap on the QTL cluster interval on chromosome 44.Annotated QTL(Chr4:81987365-142206530bp)of two groups of rapid chlorophyll fluorescence parameters detected on chromosome 4 were analyzed for functional annotation and functional enrichment of candidate genes.The candidate interval contains 508 genes,and GO category statistics get a set of genes related to a biological process and two biological functions.The biological process involved is the response to cold stress,and the biological functions involved are protein tyrosine kinase activity and electron carrier activity.According to the functional annotation of genes,a related candidate gene GRMZM2G047208 that may affect the rapid chlorophyll fluorescence of maize was predicted from genes related to the activity of electron carriers.