大田环境下玉米抗旱相关性状QTL定位

Mapping QTL for Several Drought Related Traits in Maize(Zea mays L.)under Field Condition

干旱是世界范围内导致玉米产量损失的主要因素。为了阐明玉米抗旱性的遗传基础并定位相关的数量性状位点,利用抗旱自交系临1和敏感的湘97-7组配160个F2:3家系定位群体,于2011年在湖南省作物研究所和长沙县高桥镇,分别在大田干旱胁迫和正常水分条件下进行表型鉴定。所考察性状包括抽雄至吐丝间隔、株高、千粒重和产量,用抗旱系数来衡量抗旱性。结果表明,110个SSR标记构建连锁图,图谱总长1246.1 cM,标记间平均距离11.33 cM。抗旱相关性状定位的QTL介于8～14个,共检测到43个QTL。单个QTL解释的表型变异为6.27%～18.27%。不同水分条件下定位到的QTL大多数不相同,表明对干旱胁迫的适应存在不同机制。抗旱性相关性状定位到的QTL,除第2和10染色体外,在其它染色体上都有分布,主要集中在第1染色体1.02-03区域和1.06-07区域,以及第3染色体3.04-05区域。第1染色体标记umc2224和bnlg176区间同时检测到与株高、千粒重和产量有关的QTL簇;标记bnlg1556和umc1128区间检测到与抽雄至吐丝间隔和产量有关的QTL簇。第3染色体标记umc1773和umc1311区间同时检测到与株高、千粒重和产量有关的QTL簇。这些QTL簇可能有助于通过分子标记辅助选择的方法提高干旱地区玉米的抗旱性。

Drought is a major cause of yield loss in maize production all over the world. The objective of thisstudy was to understand the genetic causes underlying drought resistance and to identify relevant quantitative traitlocus（QTL）, a F2：3 mapping populations with 160 families derived from crosses of Lin 1 （drought resistance）and Xiang97 -7 （drought sensitive）were phenotyped under the well watered and water stressed treatments in two envi-ronments including Gaoqiao and Crop institute of Chang sha in 2011. For the four target traits（ anthesis to silking in- terval,plant height, 1000 kernel weight and grain yield per planE）were measured and the drought resistance index （DRI） for each trait was considered as measurements for drought resistance. The result indicated that a linkage mapwas constructed based on I10 polymorphic simple sequence repeat（SSR） ,resulting in a length of 1246.1 cM across maize genome,with an average inter-marker distance of 11.33 cM. A total of 43 QTL were identified, with a mini- mum of 8 and a maximum of 14 for drought related traits. Phenotypic variation associated with each QTL ranges from 6.27% to 18.27%. Very few QTL were detected in two water treatments,indicating the different mechanisms mayindeed coexist that together contribute to adaptation to drought stress. The QTL for drought related traits appeared to be dispersed across l0 different chromosomes,except chromosomes 2 and 10. Most QTL for drought related traits in this study tended to cluster in some areas of the chromosome 1 and 3 ,and mainly in bin 1.02 - 03,1.06 - 07 and 3.04 -05. Two QTL clusters on chromosome 1 flanked by the markers umc2224 and bnlg176 for plant height, 1000kernel weight and grain yield per plant,and bn｜g1556 and umc1128 for anthesis to silking interval and grain yield per plant were identified. A cluster of QTL flanked by the markers umc1773 and umcl311 for plant height, 1000 kernel weight and grain yield per plant were identified on chromosome 3. These novel QTL c!usters generated in this study may be used to enhance maize drought resistance by marker assisted selection（MAS） in water limited environ- ments