the experiment was conducted in sichuan province,china in 1997,and two habitats were selected.the habitat (Ecotype i)located in the area of chuan-dian hengduan mountain was maoxian (latitude 31 41'N,longitude 103 51'E,altitude 1700 m)having a semi-arid,cool and high-irradiant climate,and the other habitat (Ecotype II)located at edge of sichuan basin was ya'an (latitude 29 59'N,iongitude 103 00'E,altitude 600 m)with a moist, warm and low-irradiant climate comparing key eco-factors at the two habitats with those at in the range of those of the high-quality apple growing areas.incontrast,none of the normal index values of ya'an fits into them. the apple cultivarsunder study were 'starkrimson' and 'golden delicious'. in each habitat, fifteen 20-year-old trees of each cultivar were selected to sample, employing standard cultivating management and spindle trirmming.