异源三倍体甜菜（VVC）无融合生殖的研究

 通过栽培甜菜与白花甜菜杂交，获得了真实杂种VC88-1（VVCC，2n=36）。用栽培甜菜对其回交，合成了异源三倍体甜菜（VVC，2n=27），它具有无融合生殖特性。异源三倍体甜菜具有两个物种的形态特征，表现为中间型，更偏向野生种。植株繁茂，叶片平展深绿色，根形不整有岔根，木质化较强。细胞学检查有丝分裂中期可清晰判定两个物种的染色体，构成独特的9长18短核型。经过几年观察选育已经选育出传递率在80%以上的无融合生殖系9个，并判定为兼性无融合生殖。利用石蜡切片研究了无融合生殖的发生过程，观察到卵细胞等8核胚囊及胚胎发育全过程，认定异源三倍体甜菜胚囊发育为蝶须型，是属于有丝分裂型的二倍体孢子生殖的无融合生殖类型。讨论了异源三倍体甜菜进一步利用的可能性。

Study of Apomixis in the Allotriploid Beet(VVC)

The hybrid VC88 1(VVCC,2n=4x=36)was from hybridization between Beta vulgaris L. and B.corolliflora Zoss..Then it was backcrossed with B.vulgaris L., the allotriploid beet(VVC,2n=3x=27) was obtained. The VVC has the character of apomixis and their morphological features display intermediate type of both species,but with a tendency to the wild species.Their plants grow luxuriantly,their leaves are flat in dark green,their root figure is disordered with branches and strong lignification. The chromosomes of both species can be clearly distinguished in mitotic metaphase by cytological observation. They form a specific karyotype:9 chromosomes are longer and 18 chromosomes are shorter.Nine lines of apomixis whose transmission rates were above 80%,have been selected after several years. They are facultative apomixis. The embryogenesis of apomixis was studied by section,the 8 nucleate embryo sac,as well as the complete process of embryo development have been observed. It was considered that the embryo sac development of allotriploid beet belonged to Antennaria type.The possibility of allotriploid beet for further utilization was discussed.