马铃薯倍性鉴定与2n配子材料筛选方法

利用叶下表皮气孔保卫细胞中所含叶绿粒数与倍性的关系,鉴定倍性;用花粉粒大小鉴别有无2n配子与估算2n配子的频率是简便易行的方法。2n配子的频率,受遗传机制与环境条件共同制约。减数分裂末期Ⅱ,是否有二、三分体出现,是确定有无2n配子产生的最可靠的方法。以四倍体为母本,二倍体2n配子材料为父本进行杂交,是测定2n配子材料受精能力及利用价值的必要手段。通过镜检发现,2n配子的形成,往往是综合作用的结果。马铃薯在正常减数分裂时,末期Ⅰ不形成二分体,第二次分裂仍在一个细胞内进行。这就为2n配子的形成奠定了细胞学基础。

THE STUDY OF THE METHOD TO IDENTIFY PLOIDY AND SELECT 2n GAMETES IN POTATO

1. It was simple and convenient to identify the ploidy in potato by the relationships between ploidy and number of chloroplasts in gardcell, to distinguish 2n gametes from normal ones, and to estimate the frequency of 2n gametes by the size of pollen grain. 2. The frequency of 2n gametes was controlled by genetic mechanism, and influenced by environment. 3. The appearance of dyads and triads at telophase Ⅱ of meiosis was the most reliable index to determine the existence of 2n gametes. 4. For assesing the polinating ability and tile value as breeding materials of producing 2n gametes, tetraploid should be used as the female parent to cross with diploids producing 2n gametes. 5. It was discovered by microscopic observation that the formation of 2n gametes was the result of mutiple action. During normal meiosis of potato, dyads were not formed at telophase Ⅰ, and the sacond divison continued in the same cell. These are the cytological foundation for the formation of 2n gametes.