鹅观草和簇毛麦属间杂种的形态学和细胞遗传学研究

Morphology, fertility and cytogenetics of intergeneric hybrid between Roegneria kamoji Ohwi and Dasypyrum villosum (L.) Candargy(Poaceae:Triticeae)

通过幼胚离体拯救培养，成功地获得鹅观草ＲｏｅｇｎｅｒｉａｋａｍｏｊｉＯｈｗｉ（２ｎ＝６ｘ＝４２，ＳｔＳｔＨＨＹＹ）和簇毛麦Ｄａｓｙｐｙｒｕｍｖｉｌｏｓｕｍ（Ｌ．）Ｃａｎｄａｒｇｙ（２ｎ＝２ｘ＝１４，ＶＶ）属间杂种，对这两个种及其杂种Ｆ１的形态学、繁育学和减数分裂配对行为进行了研究。结果表明：（１）鹅观草和簇毛麦形态差异极大，杂种Ｆ１的形态特征介于父母本之间；（２）杂交结实率低，为１１．６３％；经幼胚组织培养，获２株杂种苗；杂种Ｆ１高度不育，表明亲本间存在极强的生殖隔离，是独立的生物学种；（３）杂种Ｆ１体细胞染色体数目为稳定的２８条，减数分裂中期Ⅰ染色体配对很低，其构型为：２６．７２Ⅰ＋０．６２Ⅱ＋０．０２Ⅲ。表明鹅观草的Ｓｔ、Ｈ、Ｙ染色体组与簇毛麦的Ｖ染色体组部分同源性很低，它们的亲缘关系较远。

The intergeneric hybrids between Roegneria kamoji Ohwi and Dasypyrum villosum(L.)Candargy were successfully obtained by means of embryo culture in vitro. Studies on morphology, fertility and chromosome pairing behavior in meiosis of the parents and their hybrid F 1 were carried out in the present work. The results showed that: (1) there were obvious morphological differences between R. kamoji and D. villosum, and spikes of F 1 plants were morphologically intermediate between the two parental species; (2) the seed set of the cross was 11.63%; the hybrid plant was infertile, which indicated that strong reproductive isolation existed between the parents and R. kamoji and D. villosum were independent biological species; (3) The somatic chromosome number in root tips of F 1 hybrids was 28. Chromosome pairing at MI of PMCs in F 1 hybrids was quite low. The meiotic configuration was 26.72Ⅰ + 0.62Ⅱ + 0.02Ⅲ, which indicated that very low homoeology was detected between the St, H, Y genomes of R. kamoji and the V genome of D. villosum, and the relationship between the parental species was remote.