披碱草与野大麦杂种F1染色体加倍恢复育性与后代选育

Wide cross between Hordeum brevisubulatum (2n=28) which is of strong salt resistance and good quality of forage grass from Inner Mongolia and Elymus dahuricus (2n=42) which is of high yield and strong drought resistance from Inner Mongolia was conducted,inter-genera hybrid F1 (2n=35)was got.The results showed that the morphological characteristics of hybrid F1 tented to Elymus dahuricus,and hybrid F1 had the characteristics of short rhizome,strong tilering,salt resistance from Hordeum brevisubulatum,average heterosis was 22.95%,which was of great breeding value.But F1 was highly infertile,did not seed under open pollination,taking advantage of the genetic potential was restricted.This research program is to induce hybrid F1 chromosome doubling with colchicin to restore fertility to hybrid F1,in vitro tissue chromosome doubling is combined with real plant chromosome doubling.The effects of hormones in different proportions on induction and differenciation of callus tissue of hybrid F1 between Elymus dahuricus and Hordeum brevisubulatum and the effects of colchicin on differenciation of callus tissue undr different treatment conditions will be understood;chromosome doubling plants will be got,and will be identified based on morphology,cytology,isoenzymes and DNA molicular markers,a new germplasm of fertility restoration,resistance to drought and salt,good quality and high yield,Elymus dahuricus-Hordeum brevisubulatum,will be bred to provide new material for reseeding in arid area,establishing artificial grassland and improving ecological environment,and to promote development of animal husbandry.

选用产自内蒙古的耐盐碱性强草质好的野大麦（2n=28）与高产抗旱的披碱草（2n=42）相组配进行远缘杂交，获得了正、反交属间杂种F1（2n=35）。研究表明，杂种F1外部特征偏向披碱草，继承了野大麦短根茎、强分蘖、耐盐碱的特性，杂种平均优势达22.95%，具有重要的育种价值。但F1植株高度不育，开放授粉不结实，限制了其遗传潜力的发挥。本研究拟采用秋水仙碱诱导正反交杂种F1染色体加倍恢复育性，离体组织加倍与实体加倍相结合。探明不同的激素配比对披碱草和野大麦正反交杂种F1幼穗愈伤组织诱导及分化的影响以及秋水仙碱在不同处理条件下对愈伤组织分化的影响；获得染色体加倍植株，并从形态、细胞学、同工酶及DNA分子标记进行鉴定，进而选育出育性得到恢复、抗旱耐盐碱、优质高产的披碱草-野大麦新种质，为干旱区草地补播、人工草地建设、生态环境的改善提供新材料，从而促进畜牧业发展。

披碱草×野大麦F1具有较强的杂种优势，继承了双亲的优良特性，具有重要的育种价值。但杂种F1高度不育，开放授粉不结实，限制了其遗传潜力的发挥。本研究用秋水仙碱诱导杂种F1染色体加倍恢复育性，离体组织加倍与实体加倍相结合。建立了披碱草×野大麦F1组织培养再生体系。以幼穗为外植体，诱导愈伤组织的最适培养基为:MS+3mg/L 2,4-D+30g/L 蔗糖+7g/L 琼脂粉；愈伤组织的最佳分化培养基为:MS +1mg/L 6-BA+1mg/L NAA+30g/L蔗糖+7g/L琼脂粉；最佳生根培养基为：1/2MS +0.5mg/L IBA+0.5mg/L NAA+30g/L蔗糖+7g/L琼脂粉。秋水仙碱处理披碱草×野大麦杂种F1愈伤组织诱导染色体加倍最适的处理浓度为10mg/L，处理时间为12小时，随着处理时间的增加，绿芽数也随之降低。用10mg/L的秋水仙素溶液处理再生小植株，随着处理时间的增加，再生小植株的成活率逐渐降低，处理12h成活率最大达100%，处理72h时，成活率为66.7%；而随着处理时间的增加，再生小植株的变异率也在逐渐增加，在处理72h后达到最大37.5%。秋水仙碱处理披碱草×野大麦杂种F1秋分蘖期幼苗，成活率随着秋水仙碱处理浓度的增加、处理时间的延长而呈下降趋势，而变异率随着秋水仙碱处理浓度的增加、处理时间的延长而呈上升趋势，秋水仙碱浓度在0.1％、处理时间为36h时，诱变效果最好，获得了花粉可育率和结实率较高的植株5个，其花粉可育率为13.6%～44.8%，结实率为27.4%～57.8%。秋水仙碱处理披碱草×野大杂种F1后结实植株后代花粉可育率为90%，结实率为79.1%，说明秋水仙素处理后的F1代染色体加倍育性恢复。秋水仙碱处理杂种F1后结实植株后代叶片颜色深于杂种F1，株高高于杂种F1代，叶片长度稍长于杂种F1，叶片宽度为杂种F1的1.5倍。秋水仙碱处理杂种F1后结实株后代细胞气孔器长、宽、密度均大于杂种F1代，杂种F1体细胞染色体条数为35条，秋水仙碱处理杂种F1后结实植株后代体细胞染色体数为70，染色体数加倍。本项研究获得了育性得到恢复、抗旱耐盐碱、优质高产的披碱草-野大麦新种质，可为干旱区草地补播、人工草地建设、生态环境的改善提供新材料，从而促进畜牧业发展。