玉米氮高效组合杂种优势分析

在氮高效自交系筛选工作的基础上,利用NC-Ⅱ设计的材料进行杂种优势分析,同时探讨氮高效育种中亲本选配等问题。研究结果表明:氮高效类型中氮高效的生理机制各有特点,试验结果可以分为以吸收效率为主和以利用效率为主的两种杂交组合。总结亲本组成规律,氮高效组合的组配可分两大类型:①主要决定于母本的吸收和利用效率;②父母本的吸收效率和利用效率互补。所以,在氮高效育种中,要注重对母本氮效率性状的选择,尤其是氮吸收效率的选择以及亲本间氮效率性状的优势互补。在低氮条件下,注重选择母本穗粒重、行粒数、出籽率,父本的穗粒重、百粒重、穗粒数、株高、棒三叶叶面积等性状,同时考虑亲本的综合农艺性状,使氮高效组合的稳定性和适应性更强。

Analysis of Heterosis for Nitrogen Use Efficiency in Maize

Based on the selection for nitrogen(N) efficient maize inred lines,the heterosis of N efficiency in maize was analyzed by using the NC-II design.The criteria for parental selection in breeding for N-efficient hybrids was discussed.It was shown that N-efficient hybrids were divided into two types,one was characteristic of efficient N uptake,and the other efficient N utilization.For the parental pattern,N efficiency of a hybrid depended on N uptake efficiency and N utilization efficiency of the female parent,or the mutual compensation in N efficiency traits of the two parents.In breeding for N efficient hybrids,therefore,one should highlight the N efficiency(especially N uptake efficiency) in female parent,as well as the compensation in N efficiency traits of the two parents.For breeding of the low N-tolerant hybrids,such traits as grain weight per ear,grain number per row on the cob,grain/cob ratio are important for female parent,while the traits such as grain weight per ear,100-grain weight,grain number,height,leaf area are important for selecting the male parent.Other general agronomic traits should also be considered so that a N-efficient hybrids is adaptable to different environments.