QTL Analysis Of Lodging Resistance-related Traits In Maize(zea Mays L.)under High Plant Density

Lodging can decrease yield and quality,cause diseases,and also influence the mechanical harvest.Many studies have shown that increased the planting density is a feasible means to improve maize yield in the world.Therefore,it is meaningful to study of the genetic basis of lodging resistance under high density for high and stable yield in maize.In this study,an F2 population derived from a cross between Si287 and Si 144 was developed.QTL analysis of lodging resistance-related traits under different densities was carried out based on SSR genetic linkage map and the traits evaluated.The main analysis results were as follows:1.The statistic analysis showed that the average of lodging trait RPR,SD,IL,LR,PH and EH has significant difference and obviously transgressive segregation in 187 F3 and F4 families under different densities.2.A genetic linkage map with 152 SSR markers was constructed,which covered the maize 10 chromosomes.The map spanned a total of 1268.1cM and averagely 8.34cM between markers.Based on the molecular marker sequence and locus comparison,the linkage map was highly consistent with the maize integrated map published in the maize genome database and could be used for QTL analysis.3.Composite interval mapping(CIM)method was used to identify the QTL for these traits.a total of 27 QTLs were identified of F3 families on chromosomes 1,2,3,4,5,6,8,9 and 10 under two densities,7 QTLs were detected for RPR,5 QTLs were detected for SD,4 QTLs were detected for IL,3 QTLs were detected for LR,4 QTLs were detected for PH,4 QTLs were detected for EH.The LOD score ranged from 2.8 to 9.3,ranging from 2%to 59%of the total phenotypic variation.A total of 14 QTLs were identified of F4 families on chromosome 1,2,3,6 and 10.2 QTLs were detected for RPR,3 QTLs were detected for SD,3 QTLs were detected for IL,4 QTLs were detected for PH,4 QTLs were detected for EH.The LOD score ranged from 2.5 to 7.6,ranging from 4.3%to 17.2%of the total phenotypic variation.4.41 QTLs were detected in this study,of which 34.15%were additive effect,51.23%were partial dominant effect,7.31%were dominant effect,7.31%were over dominant affect.Additive and partial dominance effect played an important role in genetic basis of lodging-related trait.Non-additive effects play a minor role in the genetic basis of the relevant traits in this study.