Classification Of Fusarium Species From Potato Dry Rot

The main potato growing areas in Qiqihar City, Keshan Farm Heilongjiang Province of our country,the storage diseases of potato dry rot samples were collected, three varieties of potato(Y4, H525, K18) were collected from 90 samples.90 samples were isolated and purified cultures were obtained 60 Fusarium isolates.By colony culture, morphology observation and rDNA ITS and EF-1α gene sequence analysis, were identified six kinds of Fusarium were Fusarium acuminatum,F.sambucinum,F.oxysporum, F.solani, F.redolens and F.proliferatum,Their separation rates were 5.00%, 63.33%, 16.67%, 8.33%, 5.00% and 1.67%. Infection results showed that the six kinds of pathogens can lead to inoculated tuber illness,but F. sambucinum was The main pathogens of potato dry rot,another F. proliferatum was first reported on our potatoes.The six kinds of Fusarium were growing broad in the environment. Fusarium could grow from 5℃ to 30℃ and pH4 to pH11. The optimal growth conditions of F.acuminatum was 25℃, pH9; The optimal growth conditions of was F.proliferatum was 25℃, pH6, the optimal growth conditions of remaining pathogens were 25℃, pH7. F. acuminatum was suitable for potato starch and beef extract as a nutrient source. F. acuminatum was suitable for potato starch and beef extract;F.sambucinum was suitable for soluble starch and potassium nitrate; F. oxysporum was suitable for potato starch and beef extract; F. solani was suitable for soluble starch and potassium nitrate; F. redolens was suitable for potato starch and potassium nitrate; F. proliferatum was suitable for glucose and beef extract. Six kinds of pathogens can’t be a good use of fructose.Three kinds of antagonistic bacteria, seven kinds of fungi antagonistic and three kinds of pesticides were detected the inhibition rate of the six kinds of Fusarium. The test results show that B17-1、B18-2、B19-1 were inhibited the all of the Fusarium. The inhibition rate of B17-1 to F.sambucinum was the highest as 86.67%; the inhibition rate of B18-2 to F. acuminatum was the highest as 76.92%; the inhibition rate of B19-1 to F. redolens was the highest as 82.22%. B6-3、B14-1、B38-2、J38-6、Q17-4、Q39-1 and Q38-4 were inhibited the all of the Fusarium. The inhibition rate of B6-3、B14-1、J38-6 and Q39-1 to F.sambucinum were the highest that were respectively 72.22%、75.56%、82.22% and 81.11%; the inhibition rate of B38-2 to F. solani was the highest as 83.72%; the inhibition rate of Q17-4 to F. oxysporum was the highest as 75.56%; the inhibition rate of Q38-4 to F.acuminatum was the highest as 84.62%.Hymexazol, chlorothalonil and carbendazim were inhibited all of the Fusarium, as the concentrations of pesticides increased, the inhibiting effects were more obvious. The inhibition rate of 50% concentration of hymexazol to F. proliferatum was the highest as 97.47%; the inhibition rate of 50% concentration of chlorothalonil to F. oxysporum was the highest as 88.89%; the inhibition rate of 15% concentration of chlorothalonil to F. oxysporum and F. redolens were 100%; the inhibition rate of 50% concentration of carbendazim to F. proliferatum was 100%.