OTL Mapping And Analysis Of Seed Vigor Related Traits In Maize(Zea Mays L.) Under Different Conditions

Maize is one of the most important food crops, at the same time, because of therapid development of maize processing industry and other demand of industrial, theeconomic performance of maize is also expanding gradually, there is a higher requestfor the maize yield. However a determining factoin is seed for maize yield. High vigorof maize seeds germinate quickly, tidily, robustly and can resist to all kinds of badenvironmental conditions, while low vigor seeds can germinate under the rightconditions, but the speed of germination is slow, moreover they can not germinate orseedling is untidy under the bad environment conditions, and will cause great loss tothe agricultural production. In order to achieve the high yield of maize, cultivatinghigh vigor corn varieties becomes the main research direction breeders.In this study,we use a RIL population including202family,which come from ofYu537and Shen137having different performence as the research object.189SSRmarkers was select for PCR amplification and electrophoresis,and construct geneticlinkage map finally. Genetic variation of vigor traits in RIL population F10family wasidentified under the standard, artificial accelerated aging and low temperature3different germination experiment conditions. We use WinQTLCart2.5and theQTLNetwork2.0software based on mixed linear model for the whole genomescanning respectively, the QTL number and chromosome position of the vigor traitswere confirmed, and their size,direction and interactions way were analysed.The major research results are as follows:1.654SSR primers were used to detect parent polymorphism. The polymorphismprimers with clear banding pattern and good repeatability were choosed to analyseRIL populationGenotype and construct genetic linkage map,and a corn genetic linkage map including189markers was made finally,which covers corn10chromosomes, total length is2274.1cM,and the whole genome average distance is12.03cM.2. RIL population F10family was used for identify phenotype of seed vigor traitsunder3different conditions, combined with the genetic linkage map. WinQTLCart2.5software based on Composite interval mapping (CIM) was applied to identify QTL of7seed vigor trats, such as Germination percentage, Germinating energy, Germination index, Seedlinglength, Vitality index, Simple vitality index, Mean germination time and so on,25QTLs were detected which distribute on1,2,4,5and10chromosome.Under the standard germination experiment condition,5vigor traits except thegermination percentage and germination index were detected9QTL which distributeon1,2,4,5chromosome, single QTL reveals the phenotypic variation from5.39%to11.49%; Five major QTL were detected single QTL reveals the phenotypic variationfrom9.05%to11.49%.Under the low temperature germination experiment condition,6vigor traitsexcept the germination percentage were detected7QTL which distribute on2,4,10chromosome, single QTL reveals the phenotypic variation from6.70%to9.97%;qGI4（E2）,qMGD2（E2）may be major QTL that control maize seed low temperatureto phenotypic variation are9.86%,9.97%.Uuder the artificial accelerated aging germination experiment condition,5vigortraits except the germination percentage and germination index were detected9QTLwhich distribute on1,4,5chromosome, single QTL reveals the phenotypic variationfrom5.39%to11.49%; Five major QTL were detected single QTL reveals thephenotypic variation from10.27%to17.71%.qSL1-2(E1,E3)(umc1076) and qSL4(E1,E3)(umc1371-umc1101) were detectedboth under the standard and the artificial aging germination experiment conditions;qVI4-1(E1)(umc1371-umc1101)that was detected under the standard germinationexperiment condition and qVI4(E2)(umc1101)that was detected under the lowtemperature germination experiment condition have the overlapping area. The resultsshow that these QTL are the major QTL that control maize seed vigor, which caninherite stably in different environment, and the position bin4.08-4.09on chromosome4may be the important areas that controls seed vigor traits of maize.3. QTLNetwork2.0software based on mixed linear model was applied to identifyQTL mapping and epistasis analysis,12QTLs were detected which distribute on1,4,5chromosome.qGE1、 qVI1and qSVI1-1have a common marker intervalumc1071-umc2224, qGE5and qGI5have a common marker intervalumc1941-umc1225. Germinating energy, Seedling length, and Mean germination timewere detected A×E interactions effect, but the A×E interactions effect is smaller thanadditive effect. Epistasis which control Germinating energy, Germination Index andSeedling length were found,and explain phenotypic variation of a certain percentage, the results show that epistasis exist in seed vigor related traits. There are notsignificant interaction effects between epistasis and environment.It shows that, thevariation of seed vigor related traits mainly come from A and AA effectS, the effectsof environment are very small.4. The QTL distribution of seed vigor related traits relating have the same oroverlapping chromosome area.The same chromosome area such as the bin2.09(qGE2(E2), qMGT2(E2)) on chromosome2,the bin4.08-4.09(qSL4(E1), qSL4(E3), qVI4-1(E1)) on chromosome4, the bin5.04-5.05(qSL5(E3), qVI5-1(E3), qSVI5(E3)) onchromosome5, the bin5.08(qGE5(E3), qVI5-2(E3), qMGT5-2(E3)) onchromosome5,and the bin10.04-10.05(qSL10(E2), qSVI10(E2), qMGT10(E2)) onchromosome10. The overlapping chromosome area such as the bin2.08qVI2(E1) andbin2.07-2.08qSVI2(E1) on chromosome2,the bin4.08-4.09(qSL4(E1), qSL4(E3),qVI4-1(E1)) and bin4.09qVI4-2(E2) on chromosome4,the bin5.04-5.08qMGT5-1(E1) and bin5.08(qGE5(E3), qVI5-2(E3), qMGT5-2(E3)) on chromosome5.TheseQTL controlling different seed vigor related traits which one QTL control differenttraits or were adjacent to each other,using their advantage can be in favour ofmulti-effect.