Abstract: The Capsicum cultivars that had been showed steadily resistant to Myzus persicae (Sulzer) were used. This study was proceeded in 4- 6􀀁leaf stage to determine the contents of amino acids, nitrogen, sugar, proline and vitamin C in leaves. The results showed that the contents of amino acids, nitrogen, sugar, proline, vitamin C and the ratio of sugar and nitrogen were significant difference between resistant and suscept ible cultivars. Resistant cultivars had less amino acids, nitrogen, sugar, proline and vitamin C but more sugar and high ratio of sugar and nitrogen than susceptible ones; the contents of amino acids, nitrogen, sugar, proline and vitamin C of the later were 1. 1- 2. 9 times, 1. 0- 1. 7 times, 1. 4- 2. 9 times and 1. 2- 2. 6 times as much as those of the former, but the contents of sugar and the ratio of sugar and nitrogen of the former were 1. 1- 1. 3 times and 1. 3-2. 0 times as much as those of the later. The extremely signif icant difference between high resistant and high susceptible cultivars indicated that the contents of amino acids, nitrogen, sugar, proline, vitamin C and the rate of sugar and nitrogen were significantly relative to the resistance of the Capsicum cultivars to Myzus persicae(Sulzer) .

Key words: Capsicum, Amino acids, Nitrogen, Sugar, Proline, Vitamin C, Resistance to Myzus persicae(Sulzer)