老芒麦与紫芒披碱草正、反交F1代育性恢复及后代选育研究

In order to provide new forage grass varieties of high quality, high yield, high adaptability and strong stress resistance for the developing agricultural breeding industry in cropping regions and animal husbandry in pastoral region in Inner Mongolia, distant crossing between Elymus sibiricus and E. purpuraristatus were made and their interspecies hybrid F1 was obtained. One of the parent, E. sibiricus, was a tetraploid（2n＝4x＝28）cultivated specie and had large amont of leaves, good quality and high yield, and the other parent, was a hexaploid (2n＝6x＝42) wild species and had high resistance to saline, drought and lodging. the morphological characteristics, growth conditions, fertility, chromosome number of the reciprocal crosse interspecies hybrids (F1) were determined. The results showed that the reciprocal crosse interspecies hybrids (F1) were pentaploid (2n=5x=35), and showd obvious heterosis with large and softer leaves, strong tillering and regeneration ability. The hybrids(F1) had great value for breeding, but they were highly sterile (pollen fertile rate was only 0.02% ~ 0.03%). in this subject, we are planning to restore the sterility of hybrids F1 by induced chromosome doubling techniques, to identify the fertile offsprings with molecular cytogenetics method, and to create new E. dahuricus germplasm with higher fertility and biparental advantages. This project is to lay the foundation for the new breeding germplasm.

针对内蒙古自治区农区养殖业和牧区草地畜牧业发展急需开发利用优质、高产、适应性和抗逆性强的饲草新品种的实际问题，把叶量大、品质好、产籽量高的四倍体（2n＝4x＝28）栽培种-老芒麦与抗旱、耐盐碱、抗倒伏的六倍体(2n＝6x＝42)野生种-紫芒披碱草相组配进行种间远缘杂交，成功获得了正、反交种间杂种F1代，并对杂种F1代的形态特征、生长状况、育性、染色体特征等进行比较研究，发现正、反交杂种F1为五倍体（2n=5x=35），其叶片宽大，草质柔软，分蘖性和再生性均很强，杂种平均优势明显，具有重要的育种价值，但杂种花粉可育率仅为0.02%～0.03%，高度不育。本课题拟采用诱导染色体加倍和回交方法克服杂种F1代的不育性，并利用分子细胞遗传学方法对育性恢复后代进行鉴定，创造出育性较高、集合双亲优点的杂种披碱草新种质，为下一步新品种的育成利用奠定基础。

本项目针对内蒙古自治区草地畜牧业和养殖业发展急需开发利用高产、优质、抗性强的饲草新品种的实际问题，我们将叶量大、品质好的老芒麦与抗倒伏、耐盐碱的紫芒披碱草进行种间远缘杂交，获得了正、反交杂种F1代，研究发现正、反交杂种F1平均优势明显，具有重要的育种价值，但其高度不育是限制其利用的主要障碍。本研究通过诱导染色体加倍和回交方法来克服其不育性，主要研究结果如下：.（1）建立了老芒麦×紫芒披碱草杂种F1的组培再生体系，并利用秋水仙碱对愈伤组织进行染色体加倍，获得了其加倍变异植株3个，平均变异率为8.25％。.（2）分别把双亲作为轮回亲本，得到了［老芒麦×紫芒披碱草］×老芒麦、［紫芒披碱草×老芒麦］×老芒麦回交组合 BC1成活植株3株和1株，其80%体细胞染色体 数目为28条，均趋向老芒麦，花粉可育率分别为69.10%和68.72％，自然结实率分别为48%和45％。.（3）ISSR分子标记对回交后代、亲本及杂种F1代进行分析，结果表明：6个供试材料扩增出71个位点，多态性位点比率为36.6％，其遗传距离分布范围在0.2308～0.6591之间。以阈值0.5为基准，将其划分为2类：第一类为老芒麦、正交F1、［老芒麦×紫芒披碱草］×老芒麦、［紫芒披碱草×老芒麦］×老芒麦。第二类为紫芒披碱草、反交F1。这为其后代优良品系（或品种）的选育利用奠定了基础。.研究结果明确了老芒麦×紫芒披碱草杂种F1育性恢复途径，达到了预期研究目标。通过项目研究，发表研究论文3篇，完成了各项任务指标要求。