不同氮水平下玉米苗期生长性状及成熟期产量的QTL定位

 【目的】研究玉米苗期氮素利用效率相关性状与成熟期产量之间的遗传关系。【方法】以优良杂交种豫玉22两亲本Z3和87-1为基础构建的一套F8家系的RIL群体为研究材料,在高、低氮两种条件下,通过苗期水培试验和成熟期田间试验,利用复合区间作图法对玉米苗期地上部干重、根干重、总根长、根冠比以及成熟期产量性状进行了QTL定位。【结果】利用Windows QTL Cartographer 2.5 软件,在LOD＞2.5条件下共定位到22个QTL位点,其中高氮下定位到10个QTL,低氮下定位到12个QTL,两种氮水平下共位或紧密连锁的QTL位点很少,表明不同氮水平下的遗传机制不同。在第5和第7染色体上发现了苗期根系相关性状与成熟期产量之间存在连锁关系。【结论】苗期根系性状对成熟期的产量形成具有重要的作用,在氮高效遗传育种中可以把苗期根系性状作为一个重要的选择指标。

QTL Mapping of Seedling Growth Traits and Grain Yield Under Two Nitrogen Conditions in Maize

【Objective】 The purpose of this experiment was to study the genetic linkage between seedling growth and grain yield of maize under different nitrogen (N) applied. 【Method】 An F8 maize RIL population derived from an elite hybrid maize YY 22 (Z3×87-1) was used to identify the QTL for seedling growth traits and grain yield under high nitrogen (HN) and low nitrogen (LN) conditions. QTL for shoot dry weight (SDW), root dry weight (RDW), the total root length (TRL), root/shoot ratio (R/S) and grain yield (GY) were identified by composite interval mapping. 【Result】 Totally, 22 QTL were detected by using the software Windows QTL Cartographer version 2.5 (LOD＞2.5). Ten QTLs were detected under HN condition and 12 QTLs under LN condition. Few loci were detected under both LN and HN conditions for the investigated traits, suggesting there is a different genetic basis controlling maize growth at LN versus HN conditions. The genetic linkages were found between seedling growth traits and grain yield in chromosome 5 and 7. 【Conclusion】 Root traits at seedling stage are very important for grain yield. It could be a critical factor for developing N efficient cultivars in maize.