【作者】 李召锋；

【导师】 梁晓玲； 曹连莆；

【作者基本信息】 石河子大学 ， 作物遗传育种， 2009， 硕士

【摘要】 玉米是世界上最早利用杂种优势的作物之一,也是我国重要的粮食作物,其总产和单产均居第二位,对我国的粮食生产举足轻重。玉米新品种的应用是玉米增产的核心,玉米品种及其亲本自交系产量与农艺性状演变规律的研究已成为玉米遗传育种研究的热点之一。本文采用二因素裂区试验设计,以密度为主区,玉米品种及自交系为副区,通过方差分析、多重比较、相关及通径分析等方法,在新疆典型的大陆性干旱气候条件下对1950～2000年代玉米品种及1970～2000年代玉米自交系产量和农艺性状演变及产量与杂种优势的关系进行了研究。主要结果如下：1.1950～2000年代玉米品种产量持续增加。产量随年代的演变可分为三个时期。1950～1970年代产量极显著提高期,1970～1990年代增长缓慢期,1990～2000年代极显著增加期。2.1950～2000年代玉米品种在15000、45000、75000plants.ha-1密度下产量遗传增益分别为0.0732、0.1122、0.1125ton,ha-1.year-1,三种密度下平均增益为0.0993 ton.ha-1.year-1。玉米品种的耐密性没有提高。3.1950～2000年代玉米品种的千粒重、穗行数、行粒数、穗长、穗粗、秃尖长呈增加趋势；出籽率、ASI、倒折率、病株率呈减小趋势；株高、穗位高、生育期的演变无一定的规律。4.行粒数的增加是1950-2000年代玉米品种产量提高的最重要因素。穗粗、千粒重、穗长、株高的增加,生育期的延长对产量的提高也起着重要作用。出籽率的下降是1950-2000年代玉米品种产量提高的限制性因素。今后玉米品种选育中应重视对行粒数、千粒重、穗长的选择,可适当增加株高、延长生育期,同时协调与出籽率的关系。5.1970～2000年代玉米杂交种亲本自交系的产量得到了显著改良。15000、45000、75000plants.ha-1密度下产量遗传增益分别为0.0105、0.0268、0.0348ton.ha-1.year-1。三种密度平均增益为0.0240ton.ha-1.year-1。玉米自交系耐密性没有提高。6.1970～2000年代玉米自交系的千粒重、穗行数、穗长、穗粗呈增加趋势；ASI、秃尖长、病株率、倒折率呈减小趋势；行粒数、出籽率、株高、穗位高、生育期的变化无一定的规律。7.ASI的减小是1970～2000年代玉米自交系产量提高的最重要因素。行粒数、穗粗的增加对自交系产量的提高也起着重要作用。保持一定的株高和出籽率也是自交系获得高产的重要条件。8.杂种优势对产量的贡献率随密度的增加而减小。杂种优势随着年代的增加对产量的贡献率越来越小,密度越高这种趋势越明显。更多还原

【Abstract】 As one of the earliest heterosis utilization crops in the world, maize takes the second place in both total production and yield, is extremely important to grain production in China. Application of the new maize varieties is the core of yield increase. One of the hotspots in maize genetics and breeding is the evolution of maize varieties and parent inbred lines yield and its agronomic characteristics. The split-plot design of two factors which main plot are densities and assistant plot are maize varieties and inbred lines was adopted in this experiment. By the methods of analysis of variance, mutiple comparison, correlation analysis and path coefficient analysis, the evolution of yield and agronomic characteristics of maize varieties from 1950s to 2000s and inbred lines from 1970s to 2000s, as well as the relationship between heterosis and yield were stduied in Xinjiang. The main results as followed.1. The yield of maize progressively increased from 1950s to 2000s. Evolution of maize varieties yield could be divided into three stages:significantly increasing stage from 1950s to 1970s, slightly increasing stage from 1970s to 1990s, highly increasing stage from 1990s to 2000s.2. The yield genetic gains of maize varieties were 0.0732,0.1122 and 0.1125 ton.ha-1.year-1 at the density of 15000,45000 and 75000 plants.ha-1 respectively, and the average yield genetic gain was 0.0993 tan.ha-1.yeaf-1. The density-tolerance of maize varieties was not improved.3. The 1000-kernel weight, kernels per ear, kernels per row, ear length, ear diameter and bald head length of maize varieties showed increasing trend from 1950s to 2000s, but the grain index, ASI, disease plant ratio and stem and root lodging ratio showed decreasing trend. The evolution of plant height, ear height and growth duration had no regular pattern.4. The increase of kernels per row was a crucial factor raising yield of maize varieties. The increase of ear diameter, ear length,1000-kernel weight, plant height and growth duration also played important roles to yield. The decrease of grain index limited the yield increase from 1950s to 2000s. Therefore, maize variety breeding must emphasized on selection of kernels per row,1000-kernel weight and ear length, properly increasing the plant height and growth duration, coordinating the relationship with the grain index.5. The yield of parent lines of maize hybrid was well improved from 1950s to 2000s. The yield genetic gains of inbred lines were 0.0105,0.0268 and 0.0348 ton.ha-1.year-1 at the density of 15000,45000 and 75000 plants.ha-1 respectively, and the average yield genetic gain was 0.0240 ton.ha-1.year-1. The density-tolerance of inbred lines was not improved.6. The 1000-kernel weight, kernels per ear, ear length and ear diameter of inbred lines represented increasing trend from 1970s to 2000s, but the disease plant radio, stem and root lodging radio, bald head length and ASI showed decreasing trend. The evolution of kernels per row, grain index, plant height, ear height and growth duration had no regular pattern.7. The most important reason of inbred lines yield increase was the decrease of ASI. The kernels per row and ear diameter also played important roles for yield increase. Moreover, maintaining certain plant height and grain index was a major factor for achieving high yield of inbred lines.8. The contribution rate of heterosis to yield declined with density increasing. In additional, the contribution of heterosis to yield was decreasing, and the trend more obvious in height density.更多还原