关键词: 玉米, 苗期, 氮素利用效率, QTL（quantitative trait locus）

Abstract:

【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.

Key words: maize, seedling stage, nitrogen-use efficiency, QTL (quantitative trait locus)