关键词: 变叶海棠, 种群, 无融合生殖, 渗入杂交, 杂交复合体

Abstract: 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 concept ion of population, pictorial scatter diagrams and hybrid index is adopted to invest igate 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 intro gressive hybridization with M. transitoria and ( or) M. kansuensis , then maintain the new genetic variat ion through
facultative apospory. After millions of years of multiplying, it has become a complicated hybrid population hybrid complex of three species of Malus. Through invest igat ing the rate of gene recombinat ion, the mutation and gene bank of descendants, the genetic mechanism of highly resistance to adverse condit ions could be revealed. In order to maintain and increase diversities of this species, wed better culture M. kansuensis and M. transitoria in populations of M. toringoides .

Key words: Malus toringoides Hughes., Population, Apospory, Introgressive hybridization, Hybrid complex