A PRELIMINARY ANALYSIS OF THE RELATIONSHIPS BETWEEN THE DISEASE RESISTANCE OF SWEET POTATO VARIETIES AND THE AMOUNT OF AMINO ACIDS

During 1985-87, the sweet potato varieties were tested for disease resistance by using strains of sweet potato bacterial wilt (Pseudomonas solanacearum) in green houses and in wide disease areas. The results were obtained as follows: the variety 330 was resistant, Min Kang 329 and Hua Bei 48 medium-resistant, Guang Shu 15 medium-susceptible, Xin Zhong Hua and Hui Hong Zao susceptible. Statistics for the test data showed the resistance differences between the 6 varieties including 330 were remarkable or extremely remarkable. The results of test for amino acids showed that the difference in the mean amount of amino acids between the six varieties was distinct and stable. The test and analysis showed that the relationships between the disease severity and the amount of amino acids were positive inter elation. The less amount of amino acids in the variety, the more resistant the variety was. However, the more amount of amino acids in the variety, the more susceptible the variety was. Cluster analysis in an average way has proved the relationships. Fig. 1 shows the rescaled distance cluster combine.