变叶海棠种群多样性的形成与分化研究

 采用杂种指数和形象化散点图法, 探明了变叶海棠以兼性无融合生殖方式与陇东海棠和花叶海棠产生渗入杂交变异, 又以无融合生殖方式保持新产生变异的遗传, 经过数千万年的世代繁衍,形成现今这样极其复杂多样的渗入杂交群体, 该群体为3 个种的杂交复合体。由于杂种的全部或部分能育子代中发生的基因重组和增加基因的突变, 丰富了物种的基因库, 从而深入的揭示了变叶海棠具有多种高抗性的遗传机理。在变叶海棠居群内保护或栽植适量的陇东海棠和花叶海棠, 对于保持和促进变叶海棠多样性的形成与分化具有重要意义。

The Formation and Differentiation of the Diversity of Malus toringoides Hughes.

Malus toringoides Hughes., being complex diversities in morphological characters, germplasms, distributing habitats and resistance to adverse conditions, is an important apple germplasm. There are a number of different types derived from Malus toringoides .The conception of population, pictorial scatter diagrams and hybrid index is adopted to investigate the variation and differentiation among the plants in M. toringoides , M. transitoria and M. kansuensis . M. toringoides is a species of facultative apomixis. It can produce variations through introgressive hybridization with M. transitoria and (or) M. kansuensis , then maintain the new genetic variation through facultative apospory. After millions of years of multiplying, it has become a complicated hybrid population-hybrid complex of three species of Malus . Through investigating the rate of gene recombination, the mutation and gene bank of descendants, the genetic mechanism of highly resistance to adverse conditions could be revealed. In order to maintain and increase diversities of this species, we'd better culture M. kansuensis and M. transitoria in populations of M. toringoides .