【作者】 祝丽英；

【导师】 马峙英；

【作者基本信息】 河北农业大学 ， 作物遗传育种， 2012， 博士

【摘要】 高产是玉米育种的主要目标。研究表明种植密度的增加、株型的改善和穗部性状的优化是玉米产量提高的主要原因。因此,进行株型和穗部性状的遗传研究对玉米育种具有重要的意义。本研究构建了以农系928为遗传背景玉米导入系群体,利用导入系和DH系两种群体对株型和穗部性状进行QTL定位,并分析了2种密度处理下的株型和穗部性状的遗传基础。此外,还对选育的雄性不育系进行育性和胞质类型鉴定及遗传分析。主要结果如下:1.分别以4个自交系为供体亲本,农系928为受体亲本,通过4代回交和2-3代自交,结合SSR分子标记选择,构建了由161个导入系组成的玉米导入系群体。该群体共导入986个供体片段,每个导入系中含有2-13个导入片段,平均6.24个。导入片段长度在4.24cM~269.20cM,平均长度65.04 cM。导入系的背景回复率为84.25%~97.59%,平均92.64%。不同供体来源的导入系,导入片段的数目和长度存在一定的差异。不同染色体上,导入片段的数目和长度也各不相同。这些导入系为开展玉米QTL精细定位和功能基因组研究提供了材料。2.基于导入系群体连续2年的株型和穗部性状表型值,分别检测到30个株型性状QTL和18个穗部性状QTL。这些QTL分布于10条染色体上,单个QTL可解释的表型变异在7.00%~28.75%。控制不同性状的QTL定位在相邻或相同的染色体区域,在第3染色体umc1399-umc1307区间和第6染色体bnlg1538-umc159及umc1614-bnlg1154区间出现了3个QTL的富集区。3.在60000株/hm~2和90000株/hm~2两种密度处理下DH群体的株高、穗位高、节间数、平均节间长、茎粗和穗位系数6个株型相关性状均存在极显著差异,株高和穗位高均与穗高系数呈显著正相关,但穗位高与穗位系数的关系更为密切。检测到株型相关性状的27个加性QTL和4对上位性QTL,其中7个QTL与环境存在显著互作。只有7个株型性状的QTL在两种密度下同时被检测到。发现位于第1、8、9、10染色体上的6个重要染色体区段存在株型性状的环境钝感主效QTL(在2个以上环境中检测到,且贡献率大于10%)。4.两种密度下DH群体的穗长、穗粗、行粒数、秃尖长和粒宽存在显著差异,而穗行数、粒长、粒厚和百粒重差异不显著。检测到穗部性状的14个加性QTL和1对上位性QTL,其中3个QTL与环境存在显著互作。只有3个穗部性状QTL在两种密度下同时被检测到。发现位于第4、5染色体上的2个重要染色体区段存在穗部性状的环境钝感主效QTL。5.在自交系1261和农系928的回交后代中发现一个玉米雄性不育系—农系928cms-Q1261。该系雄穗无花药外露,花粉败育彻底,不育性状稳定。质不育基因来自自交系Q1261,为S型;核不育基因来自农系928,由1对隐性基因控制。小孢子从单核晚期开始自溶,成熟期完全降解。自交系郑58和PH6WC能保持其不育性。更多还原

【Abstract】 The development of yield is the main objectives in maize breeding. Many studies have shown that the increased plant density, optimization of plant type and ear traits are the major contributor to maize yield improvement in China and elsewhere in the world. Therefore, the genetic dissection of plant type and ear traits is especially important in maize breeding. In the study, a set of introgression lines (ILs) were produced using the inbred line NongXi928 as recipient parents by means of marker-assisted backcrossing. Both ILs and DH lines were utilized to QTL analysis for plant type and ear traits. Furthermore, the genetic basis of plant type and ear traits were investigate under two different densities treatment. Meanwhile, a new cytoplasmic male sterile line discovered in the backcrossing population was indentified for type of male sterile, stage of microspore abortion and genetic mechanism. The major results are as follows:1. A series of 161 introgression lines were developed with NongXi928 as the recurrent parents and 4 elite inbred lines as donor, respectively through 4 cycles advanced backcross, 2-3 cycles self-cross and SSR-based marker-assisted selection. Genetic evaluation showed that 986 segments from the donor line were introgressed into NongXi928. The number of introgressed segment ranged from 2 to 13 with an average of 6.12 per lines. The average length of introgressive segment was 65.04 cM, varying from 4.24 to 269.20 cM. The length and the number of introgressed segment varied along with the different donor and different chromosomes. Recovery of the Nongxi928gnome ranged from 84.25% to 97.59% with an average of 92.64% in this ILs poplation. These ILs could be used into fine mapping of QTL and functional genomics researches in maize.2. Based on the phenotype of plant type and ear traits that were investigated in two years, 30 QTL for plant type related traits and 18 QTL for ear traits were detected in ILs population. Those QTL were mapped on 10 chromosomes and explained 7.07%–28.75% of the phenotypic variance. Some QTL for diverse traits were located in the same or adjacent chromosome region. Three QTL-rich regions were formed on chromosome 3 in the interval umc1399-umc1307, chromosome 6 in the interval bnlg1538-umc159 and umc1614-bnlg1154.3. Differences between density of 60,000 and 90,000 plants per hectare were significant for plant height (PH), ear height (EH), internode number (IN), average internode length (AIL), stalk diameter (SD) and ear height coefficient (EHC) in the DH population. Both PH and EH were positively significantly correlated with EHC, but EH had more influence on EHC than PH. Twenty-seven additive QTL and four pairs of QTL with epistatic effect were detected for the investigated traits, of which seven QTLs with significant environment interactions were indentified. Only seven QTL were detected simultaneously under both densities. Six important regions distributed on chromosome 1, 8, 9 and 10 were found to exist constitutive QTL (detected in more than two environments, with contribution rate more than 10%) for plant type related traits.4. The ear length, ear diameter, kernel number per row, length of bare tip and kernel width had significant differences, but kernel row number per ear, kernel length, kernel thickness and 100 Grain weigh had no differences under the two densities treatment in DH population. Fourteen additive QTL and one pair of QTL with epistatic effect were detected for ear traits, of which three QTL with significant environment interactions were indentified. Only three QTL were detected simultaneously under both densities. Two important regions distributed on chromosome 4 and 5 were found to exist constitutive QTLs for ear traits.5. A male sterility line ( NongXi928cms-Q1261) was discovered in the BC3F1 population obtained using Q1261 as the donor genotype and NongXi928 as the recipient genotype. The male sterility characteristic of NongXi928cms-Q1261 was stable, no anthers exposed on tassel and pollen aborted completely. The cytoplasmic male sterile gene, which was classified into S type of CMS, originated from Q1261, and its nuclear sterile gene originated from NongXi928, which was controlled by a pair of recessive genes. The microspores started degrading at the late stage of microspore and degenerated completely at the mature pollen stage. Such male Sterility of NongXi928cms-Q1261 can be maintained by Zheng58 and PH6WC.更多还原