【作者】 吴锁伟；

【导师】 李玉玲；

【作者基本信息】 河南农业大学 ， 作物遗传育种， 2003， 硕士

【摘要】 爆裂玉米种质资源存在产量低、抗倒性差、对病虫害及环境胁迫缺乏抗耐性等缺点，从而严重制约着其育种水平和效率的进一步提高。因此，迫切需要拓宽爆裂玉米的种质基础，并探索适宜的高效育种途径。前人初步研究表明，可以利用普通玉米改良爆裂玉米种质。但对两类材料的种质关系、爆裂玉米种质的优势类群划分及普通玉米种质的高效利用尚缺乏系统研究。 本研究利用代表两类种质的四套NCⅡ遗传交配设计较为系统地探讨了爆裂与普通玉米的种质关系、正反交效应、选系方法对普×爆后代的选择效果、（爆×普）自交高代选系的组配利用价值和效果，同时对爆裂玉米自交系进行优势类群划分，为高效利用两类种质、组配适宜的普×爆选系基础材料以及确定后代选育方法提供理论依据。 利用按照NCⅡ遗传交配设计组配而成的60个普×爆（10×6）F₁组合，通过两个地点15个性状的配合力分析，研究爆裂与普通玉米的种质关系，并根据SCA对爆裂玉米自交系进行了聚类分析与优势类群划分；以45个普×爆正反交F₁组合为材料，分析了15个性状的正反交效应；以20个普×爆（5×4）组合的8个世代(P₁，P₂，F₁，F₂，BC₁₁，BC₁₂，BC₂₁，BC₂₂)为材料，分析了不同爆裂、普通玉米种质及自交、回交一代、回交二代主要性状的表现特点；以24个（爆×普）自交高代选系的168个（24×7）测交组合为材料，分析了自交高代选系的配合力、聚类结果与其亲本种质的关系、组配效果及进一步利用价值。结果表明： 1．爆裂玉米自交系的GCA存在显著差异，N09具有较高的组配利用价值。膨化倍数的SCA仅濮阳点的374×N09为极显著正值，穗粒重仅长葛点的改3×N04、豫87-1×N14和濮阳点的昌7-2×N14为（极） 显著正值。爆X普F；组合的穗粒重均有很大提高，但膨化倍数较差， 无直接利用价值。6个爆裂自交系分为4类，分类结果与育种实际完 全相符。各性状不存在正反交效应。 2．普＼爆F。代膨爆特性较差，从中连续自交选育出优良爆裂玉米 自交系的可能性较小；回交可以快速恢复爆裂亲本的优良膨爆特性， 11个组合经过一代回交、9个组合经过两代回交即可基本上达到爆裂 亲本的水平，而且穗粒和植株性状也有明显改进。但回交二代oC。；、 BC。。)较 F；、回交一代oC1、BC＊的穗粒和植株性状均有不同程度的 变劣。因此，具体回交代数要根据不同组合回交一代的效果和回交两 代的穗粒和植株性状表现来确定。 3．不同普X爆组合后代的膨爆特性、穗粒和植株性状差异显著， 但与普通玉米自交系所属的优势类群并无明显相关。F；与巳的各主要 性状及回交世代的膨爆特性存在极显著相关，可以根据F；的性状表现 进行早代选择，从而重点对忧良组合实施选择。各穗粒和植株性状与 3个膨爆特性指标间均呈极显著负相关，在普X爆组合后代的选择过 程中，协调各穗粒和植株性状与膨爆特性之间的关系尤其重要。 4．24个（爆X普）高代自交选系的GCA存在显著差异，BP02、BP03、 BP04、BP12、BP14可进行广泛测交＼组配利用。24个选系分成4个优 势类群和 10个亚群，聚类结果与其双亲的系谱差异并不存在必然联 系。各测交组合作为普通型品种的直接利用价值不大。 本文还对爆裂玉米自交系的种质基础和优势类群划分＼利用普通 玉米种质改良爆裂玉米的可行性及其高效利用、普X爆后代的选系方9 法、膨爆特性的遗传及性状相关等问题进行了讨论。更多还原

【Abstract】 The fewer genetic sources, much lower grain yield, and worse agronomic traits of popcorn germplasm, comparing with normal corn, make it very urgent to improve popcorn germplasm with various methods.6 popcorn inbreds and 10 normal corn inbreds, representing 5 normal corn heterotic groups, were chosen to make 60 normal corn xpopcorn F1 crosses using NCII genetic design. All the 60 crosses were evaluated in replicated experiments with randomized complete block design at two locations (Changge and Puyang) in 2002.The combining ability and cluster analysis of 15 characters, including 3 popping characters, 9 ear-kernel characters and 3 plant traits showed that the GCAs of 6 popcorn inbreds were different significantly. Considering all the characters, N09 was much better than other 5 lines in direct utilization. The SCAs of popping fold of 374xN09 at Puyang, and Gai3+N04, Yu87-l+N14 at Changge and Chang7-2+N14 at Puyang for ear-kernel weight w ere positive significantly. The ear-kernel weight of all F1 crosses was much higher than elite popcorn hybrid Yubao 2,but the popping characteristics were very low, so such crosses had no value in direct utilization. According to cluster analysis of SCA values, the 6 popcorn inbreds were divided into 4 heterotic groups, which were in complete agreement with popcorn breeding before.The 15 characters of 8 populations (P1, P2, F1 F2, BC11, BC12, BC21, BC22) of 20 normal comxpopcom crosses (5 normal corn inbreds crossed with 4 popcorn inbreds) were evaluated at Changge in replicated experiments using split-plot design, with crosses were as the main plots and population as the subplots. The results indicated that popping characteristics of normal com xpopcorn crosses were very low, so it was difficult to select elite popcorn inbreds from such populations through traditional pedigree selection method. It was an effective way to recover the elite popping characteristics of popcorn inbreds through backcrossing to them. For 11 crosses only one backcross was very effective and other 9 ones two backcrosses and ear-kernel characters were improved accordingly. But the ear-kernel characters of BC2 (BC21,BC22) were worse than F2 and BC1 (BC11 BC12), so suitable backcrosses depended on the results of diverse BC1 and the ear-kernel characters of BC2.24 advance pedigree selected lines from popcomxnormal com crosses and 7 popcorn inbreds were chosen to make 168 testcrosses using NCII genetic design. All the crosses were planted in replicated experiments with complete randomized block design at Change in 2002. The results suggested that the GC As of the 24 selected lines were different significantly. 5 of the 24 lines, BP02, BP03, BP04, BP12, BP14, were better than the others, which should be crossed extensively to choose commercial popcorn hybrids in late breeding. The cluster results showed that the 24 lines were divided into 4 heterotic groups and 1 0 subgroups, which was not in agreement with their parental germplasm. These testcrosses had little value in commercial utilization, due to the failure of combination of popping characteristics with kernel yield.The popping and ear-kernel characters among normal corn xpopcom crosses were different significantly. So it was very important to choose suitable normal com germplasms and make elite normal corn xpopcom crosses for popcorn inbreds selection. It seemed that the popping characteristics of such crosses had no clear relationship with the heterotic groups of normal corn parents. The correlation showed that the ear-kernel characters of popcorn parent lines had significant correlations with FI, but they were not significant for popping characters. Therefore, through early test selection, we could concentrate all our forces to elite crosses, enhance selection effect, and reduce the cost in further selection.The correlation between 3 popping characteristics and all ear-kernel characters were negative significantly, so it was very important to consider their relationship and decide suitable criteria in popcorn indreds selection.T更多还原