糯玉米芽苗期耐盐性鉴定及相关分子标记筛选

Identification of salt tolerant germplasms and screening of related molecular markers in waxy maize at germination and seedling stages

为了给糯玉米耐盐育种提供种质材料和分子标记信息,以85份糯玉米自交系为材料,在糯玉米发芽期和苗期测定了存活时间、单株存活率、相对发芽率、相对幼芽长和相对胚根长等5个耐盐性状,并利用71对SSR标记扫描基因组,进行了耐盐种质和相关分子标记的筛选研究。结果显示,5个耐盐性状在糯玉米自交系间存在极显著遗传差异,变异幅度大;筛选到在各耐盐性状上表现较好的种质各5份,其中自交系NA18和NA30-2在多个性状上表现较好;共扩增出340个差异片段,平均每对引物4.78个,引物多态性信息量(PIC)值为0.249～0.876,平均为0.479,供试群体被划分为5个亚群;共检测到9个标记位点分别与5个耐盐性状显著关联,其中1个位点同时与2个性状存在显著关联。以上结果说明,在糯玉米育种上对耐盐性状的改良存在较大的遗传空间,筛选到的耐盐性种质和分子标记具有一定的育种价值。

Salt stress affects the growth and development of waxy maize.The aim of the present study was to provide germplasms and molecular information of waxy maize for salt tolerance.For this purpose,a panel consisting of 85 waxy maize inbred lines was measured for five salt tolerance traits,percentage of plant survival,plant survival days,relative germination rate,relative plumule length,and relative radicle axis length,at germination and seedling stage.In addition,the panel was genotyped by 71 pairs of genome-wide simple sequence repeat（SSR） markers.Linkage disequilibrium of pairwise loci and population structure were analyzed,and the association analysis between SSR loci and the five measured traits was performed using TASSEL GLM（general linear model） program.The results were as follows.The five salt tolerance traits demonstrated significant difference and wide variation range in waxy maize inbred lines.Five elite inbred lines with better performance under salt stress were selected,among which,NA18 and NA32-2 were the best 340 specific DNA bands were detected in the panel,averagely 4.78 polymorphic fragments for each primer.The value of polymorphism information content（PIC） for each SSR locus varied from 0.249 to 0.876 with an average of 0.479.A model-based population structure analysis divided the population into five subpopulations,three of which have been reported previously,while the other two are newly developed.A total of nine loci,located on chromosomes 1,2,5,5 and 9,were detected to be associated with the five salt tolerance traits significantly,respectively,which explained phenotypic variation ranging from 7% to 29%.The marker umc2012 on chromosome 1 was detected to be associated with the two traits,percentage of plant survival and plant survival days,simultaneously.These results suggest that the identified germplasms and molecular markers in the present study may be useful for the breeding of waxy maize.