| The production of maize in our country was 208.12 million tons,3.83 million tons ahead of the production of rice,which become the largest food crop in China in 2012.Phosphorus is one of the major indispensable element to the growth of plants,which plays an important role for the formation of yield and quality.Phosphorus is non-renewable mineral resources,therefore soil phosphorus deficiency is one of the main factors that limit crop yield in agricultural production today.Root system is an important part of the maize,which has much important quantitative traits.QTL mapping technology provides a powerful tool for the study of complex quantitative trait genetic relationship,with the development of molecular biology,maize traits genetic research has been much progress in recent years.Therefore research of plant genetic mechanisms,explore phosphorus QTL loci nurturing tolerance to low phosphorus maize varieties has important theoretical reference and practical significance.In this study,Low phosphorous tolerant maize inbred lines X178 and low phosphorus-sensitive inbred lines 9782 was used to build F8 family RIL population containing 219 as materials.We used sand culture system,the root traits of the group phenotypic were identification in 2012,then we created a genetic linkage map containing 165 SSR markers,and used a composite interval mapping(CIM)the initial positioning of the QTL important root traits.The main results of this study are as follows:1 A genetic linkage map of 165 SSR markers was constructed,total map length 1500.33cM,the average distance between the marks 9.09cM,1 to 10 chromosome markers were:25,21,11,21,1918,13,15,8,14 markers,the average distance marked on each chromosome:10.08cM 9.09cM 5.93cM 7.64cM 9.31cM 9.23cM 9.14cM 9.96cM,10.76cM9.6cm.The map is basically the same to published maize molecular genetic map.2 Compared low phosphorus levels to normal levels in RIL population total root length,total root area,average diameter,root number,LRL,LSA,LRV,LRT,shoot weight,root dry weight,leaf length,leaf width decreased by 32.4%and 35.1%,37.7%,46.6%,37.8%,36%,34.8%,47%,66.2%,40.4%,22.8%,37.1%,root to shoot ratio increased 75.3%.Under normal phosphorus levels:leaf width,LSA,LRV,LRL,root diameter,leaf length,total root length,root length,MRL has higher heritability;Under low phosphorus levels:root diameter,LRV,LRL,LSA,total root length,LRT,root tip has high heritability.Seeding root traits and aboveground traits has a very high correlation in the population.Under normal conditions of phosphorus leaf dry weight and root traits were all positively related phenotypes,had a outstanding positive linear correlation to root length,root area,root volume,root dry weight.Under phosphorus deficiency leaf dry weight and root traits were all positively related phenotypes,had a outstanding positive linear correlation to total root length,root area,root volume,root dry weight.3 Composite interval mapping QTL initial position,normal phosphorus levels is positioned to 16 QTLs,which total root length detected a QTL,located on chromosome 1,root surface area detected a QTL on chromosome 1;average root diameterdetected a QTL is located on chromosome 7;root volume detected a QTL located on chromosome 1;less than 0.5mm in diameter root length detected a QTL located on chromosome 1;diameter less than 0.5mm root volume detectionone QTL located on chromosome 1;leaf dry weight detected a QTL located on chromosome 1;root dry weight detected a QTL located on chromosome 1;longest root length detected two QTLs were located Ion chromosome 6;seedling leaf length detected two QTLs were located on chromosome 2,5;seedling leaf width detected three QTLs were located on chromosome 1,1,5;leaf number detection to a QTL located on chromosome 6.In this study the total root length,root area,root volume within 0.5 mm in diameter respectively in two environment as in bin1.06 and bin1.03 area,that control the genetic basis of the three traits may be the same.Root tips,Root Tips less than 0.5mm in Diameter,Ratio of Root to Shoot only under low phosphorus condition detected QTL,gene is likely to prove that control these three traits closely related to low phosphorus stress.4.Navigate to the root of this study and related QTL for other groups,navigate to the root of QTL similar chromosomal regions,which is also found in positioning root hotspot QTL region binl.06 control multiple root traits QTL.Simultaneously,this study found multiple QTL on bin1.03 under phosphorus deficiency control root traits. |
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