【作者】 冯云超；

【导师】 唐祈林；

【作者基本信息】 四川农业大学 ， 作物遗传育种， 2010， 硕士

【摘要】 本研究以玉米自交系、大刍草及其杂种F1为材料,探讨了玉米与大刍草的可杂交性及其杂种F1的杂种优势,旨在为利用玉米与大刍草杂交选育高产优质饲草品种提供理论依据；另外,对玉米与大刍草杂交选育的一个饲草玉米—玉草2号进行了栽培密度实验研究。试验取得主要结果如下：1玉米与大刍草可杂交性、杂种F1减数分裂行为及其花粉育性结果表明,玉米与墨西哥类玉米亚种、小颖类玉米亚种、委委特南戈类玉米亚种、二倍体多年生类玉米种、尼加拉瓜类玉米种、繁茂类玉米种和四倍体多年生类玉米种的杂种F1减数分裂终变期染色体配对构型分别为0.080Ⅰ+9.960Ⅱ、0.267Ⅰ+9.867Ⅱ、0.573Ⅰ+9.713Ⅱ、0.667Ⅰ+9.667Ⅱ、0.747Ⅰ+9.627Ⅱ、0.760Ⅰ+9.620Ⅱ和4.773Ⅰ+5.173Ⅱ+4.960Ⅲ,染色体相对紊乱系数分别为0.004、0.014、0.030、0.034、0.039、0.040和1.899,花粉育性分别为92.51%、90.69%、83.33%、75.46%、67.08%、65.57%和17.66%；玉米与各个大刍草种(亚种)杂交均能结实,结实率差异极显著。结果说明,它们杂种F1花粉育性与减数分裂染色体相对紊乱系数存在密切关系,花粉育性与减数分裂染色体相对紊乱系数反映了玉米与大刍草各种的亲缘关系。本研究首次对玉米与最近发现的尼加拉瓜类玉米种的杂种F1减数分裂过程染色体行为和花粉育性进行报道,由染色体配对构型、染色体相对紊乱系数和花粉育性推测尼加拉瓜类玉米种与繁茂类玉米种亲缘关系最近。2杂种优势试验分析表明,玉米与大刍草间杂种F1存在较强的杂种优势。就饲草产量及其产量性状中亲优势而言,以鲜、干草产量优势最大,分别为0.9623和0.8095,倒4叶叶面积、总茎粗和主茎粗优势次之,分别为0.6203、0.3824和0.2941,草长、分蘖和绿叶片优势最小,分别为0.1541、0.1328和0.0560。饲用价值中亲优势方面,饲用成分产量中亲优势高于饲用成分含量。饲草产量和饲用价值综合比较,尼加拉瓜类玉米种和委委特南戈类玉米亚种与栽培玉米亚种组配的杂种F1杂种优势相对较高。研究还发现玉米-大刍草杂种F1抽雄始期早于亲本大刍草。结果说明,通过玉米与大刍草杂交可以提高饲草产量和饲用价值。3对14份玉米-大刍草杂种F1单株产量与产量性状分析表明,单株产量与产量性状均存在较大的变异,材料间除主茎粗外,其余性状差异均达到显著或极显著水平。不同性状间变异程度不同,其中单株产量的变异最大,变异系数达47.30%。单株产量与分蘖负相关,与主茎粗显著正相关,与草长、绿叶、总茎粗和倒4叶叶面积极显著正相关。对单株产量直接作用大小依次是草长、分蘖、总茎粗、绿叶、主茎粗和倒4叶叶面积。结果说明,草长是影响杂种F1单株产量的重要性状。4对14份玉米-大刍草杂种F1的粗蛋白(CP)、粗脂肪(EE)、酸性木质素(ADL)、酸性洗涤纤维(ADF)、中性洗涤纤维(NDF)和体外干物质消化率(IVDMD)6个饲用价值指标分析表明,各饲用价值性状变异较大,各性状杂种F1间差异均达到极显著水平。不同饲用价值性状变异程度不同,其中EE的变异系数最大,达到30.37%。IVDMD与ADL、ADF和NDF含量呈极显著负相关,与CP和EE含量呈极显著正相关。影响饲草饲用价值的性状依次是NDF、IVDMD、ADF、CP、ADL和EE含量。5玉草2号栽培密度试验结果表明,在试验设计的密度下,玉草2号鲜、干草产量均最高,川单14×墨西哥大刍草其次,墨西哥大刍草最低；三种饲草鲜、干草产量随着密度增加呈“低-高-低,,的变化趋势；它们的最适宜栽培密度分别为75000、75000和52500株.hm-2。最适密度下饲用价值比较表明玉草2号和川单14×墨西哥大刍草CP、ADF、NDF和EE 4种饲用成分产量均显著或极显著高于墨西哥大刍草,其CP和EE含量均低于墨西哥大刍草；玉草2号和墨西哥大刍草相对饲用价值(RFV)差异不显著,均显著高于川单14×墨西哥大刍草。茎秆是玉米-墨西哥大刍草杂种主体,叶片是墨西哥大刍草干物质产量构成的主体,三种饲草草产量和饲用价值差异来自其生物学特性的显著差异。综上所述,玉米与不同大刍草种(亚种)都能结实。玉米-大刍草杂种F1饲草产量和饲用价值均具有杂种优势,尼加拉瓜类玉米种和委委特南戈类玉米亚种与栽培玉米亚种组配的杂种F1的饲草产量和饲用价值相对较高,是与玉米杂交选育高产优质饲草的最佳父本。玉草2号最适宜栽培密度为75000株.hm-2。更多还原

【Abstract】 In order to provid theoretical evidence for high yield and high quality forage selected by crossing maize with teosinte, the crossability between maize and teosinte, and heterosis of the maize-teosinte hybrids F1 were explored while the maize-teosinte hybrids and their parents were used as materials. In addition, the effect of plant density on yucao 2 was investigated in the study. The main results were as follows:1 The crossability between maize and teosinte, the meiosis and pollen fertility of the maize-teosinte hybrids F1 were investigated. The results shown that the chromosome pariring configuration in meiosis diakinesis per pollen mother cell (PMC) of Z. mays×Z. Mexicana, Z.mays×Z. parviglumis, Z.mays×Z. huehuetenangensis, Z.mays×Z. diploperennis, Z.mays×Z. nicaraguensis, Z. mays×Z. luxurians and Z.mays×Z.perennis was 0.080Ⅰ+9.960Ⅱ,0.267Ⅰ+9.867Ⅱ,0.573Ⅰ+9.713Ⅱ,0.667Ⅰ+9.667Ⅱ, 0.747Ⅰ+9.627Ⅱ,0.760Ⅰ+9.620Ⅱand 4.773Ⅰ+5.173Ⅱ+4.960Ⅲ, respectively. The chromosome relative chaotic coefficient in meiosis of hybrids F1 was 0.004,0.014,0.030,0.034,0.039,0.040 and 1.899, respectively. The pollen fertility of hybrids F1 was 92.51%,90.69%,83.33%,75.46%,67.08%, 65.57%and 17.66%, respectively. The teosinte can be directly crossed with maize, and the hybridization seed rate had highly significant deviation. In conclusion, the information on pollen fertility and chromosome relative chaotic coefficient appearanced a close relationship, which is useful in the assessment of genetic relationships. The meiosis behaviors and pollen fertility of Z. mays-Z. nicaraguensis hybrid was first reported in this study, supposed that Z. nicaraguensis discovered recently was more genetically closer to Z. luxurians than to other teosintes.2 The forage yield, yield characters and feeding value heterosis of maize-teosine hybrids were investigated. The results shown that high levels of heterosis were obtained in the hybrids F1 between maize and teosinte based on two years data. For forage yield and yield traits, the fresh matter yield and dry matter yield had the highest heterosis level, the average heterosis was 0.9623 and 0.8095, respectively, and the area of the reciprocal fourth leaf, total stem perimeter and main stem perimeter took second place, the average heterosis was0.6203,0.3824 and 0.2941, respectively, and the grass length, tiller and green leaves had the lowest heterosis, the average heterosis was0.1541,0.1328 and 0.0560, respectively. The heterosis of feeding composition yield characters was higher than feeding composition content characters. The hybrids between maize and Z. nicaraguensis, Z. huehuetenangensis had the relative higher forage yield and feeding value heterosis. Moreover, the research revealed initial tasseling stage of maize-teosinte hybrids F1 were earlier than teosinte. The result indicated that it could improve the forage yield and feeding value by distant hybridization between maize and teosintes.3 The fresh yield of single plant and yield traits among 14 maize-teosinte hybrids F1 were investigated The main results were that forage yield and yield traits per plant had significant or highly significant deviation, except for the total stem perimeter, and the coefficient of variation (CV) of fresh yield of single plant was the highest (47.30%). Fresh yield of single plant was negatively associated with tiller, significantly positively associated with main stem perimeter, and highly significantly positively associated with grass length, green leaves, total stem perimeter and area of the reciprocal fourth leaf. The order of direct effect on fresh yield of single plant from large to small was grass length, tiller, total stem perimeter, green leaves and area of the reciprocal fourth leaf. The result indicated that the grass length was an important character for improvement of fresh yield of single plant of maize-teosinte hybrids F1.4 The main result of the feeding value traits among 14 maize-teosinte hybrids F1 indicated that all the feeding value traits had highly significant variation, and the CV of EE was the highest (30.37%). The correlation analysis of quality traits among maize-teosinte hybrids F1 showed that in vitro dry matter digestibility (IVDMD) had a highly significant negative correlation with acid detergent lignin (ADL), acid detergent fiber (ADF) and neutral detergent fiber (NDF), but a highly significant positive correlation with crude protein (CP)and ether extract (EE). The order of the traits influencing forage from large to small was NDF, IVDMD, ADF, CP, ADL and EE.5 The plant density experiment of yucao 2 main results were as follows:The fresh and dry matter yields of the three forage, which showed the change of "low-high-low" with the increase of planting density, and the optimum plant density was 75000,75000 and 52500 plant·hm-2, respectively. The fresh and dry matter yields were the highest in the Yucao 2 and lowest in Zea mexicana among all planting density. The yields of CP, ADF, NDF and EE in Yucao 2 and chuandan14×Zea Mexicana were higher than in Zea mexicana significantly or high significant, however, the content of CP and EE was the highest in Zea mexicana.The Relative feeding value(RFV) in Yucao 2 had no significance with that in Zea mexicana and were higher than in chuandanl4×Zea mexicana significantly. Main component of dry weight was leaves in Zea mexicana, while stems in Zea mays-Zea mexicana hybrids. In conclusion, the differences of matter yield and feeding value among the three forage derived from the significant differences among their biological characteristics.In conclusion, the maize and teosinte were cross-fertile. Both forage yield and feeding value of maize-teosinte hybrids F1 exhibited strong heterosis. The hybrids of Z.mays×Z. nicaraguensis and Z.mays×Z. huehuetenangensis had the relative higher forage yield and feeding value, which indicated that the Z. nicaraguensis and Z. huehuetenangensis were the best pollen parent for maize to select forage breed. The optimum plant density for yu cao 2 was 75000 plant-hm-2.更多还原