Abstract:

Somatic chromosome numbers of 37 forms (representing 22 species) of apples

in China were counted using wall-degradation and hypotonic method.  Among the species in-

vestigated 3 categories of chromosome numbers, i.e. 2n=34, 51 and 68 are confirmed.   The

chromosome numbers of the following species are here first reported: Malus ombrophila 2n=

34, M. prattii 2n=34, M. melliana 2n=34, Zhaojiaohonghua (M. sp.) 2n=34, and M. asiatica

var. 2n=68. Polyploids (including infraspecific polyploids) account for 41% of the total num-

ber of the species investigated. 51 is a predominant number.  It is suggested that ploidy varia-

tion is an important pathway in apple evolution in China, and triploid may be considered as

a suitable evolution grade.  There are rich apple germplasm resources in China.  The systema-

tic studies of this genus are obviously essential.

Key words: Malus, Chromosome number, Polyploid