Abstract: The genetic diversity and genetic structure of four Malus sieversii eco-geographical populations from Xinjiang, China were studied　by SRAP marker. The results showed that 209 bands were amplified totally by ten pair SRAP primers, of which 206 bands (98.56%) were polymorphic in the species level and the number of polymorphic bands (A) was 180, 169, 178 and 165, respectively, at Gongliu, Xinyuan, Huocheng, and Yumin populations. The average panmictic heterozygosity (hs = 0.3037 ± 0.0058) in the Gongliu population was the highest, followed by the Huocheng population. UPGMA cluster analysis and genetic differentiation among populations showed that there had closer genetic relationship between Gongliu and Xinyuan populations and between Huocheng and Yumin populations and lower genetic variation between the populations. For M. sieversii, genetic variation within population, which was higher than between the populations, accounted for 87.9% of total variation. The principal coordinates analysis showed that the four populations were relatively independent populations, in which between the Gongliu and Xinyuan populations and between Huocheng and Yumin populations had higher gene exchange. On the basis of the study of population genetic structure and genetic diversity, Gongliu population should be given a high priority consideration in Malus sieversii germplasm conservation both in situ and ex situ.

Key words: Malus sieversii, SRAP markers, Genetic diversity, Population genetic structure, Conservation