Study On The Occurrence Rule Of Sunflower Yellow Wilt And Resistance Mechanism Of Sunflower To Verticillium Dahliae

Sunflower Verticillium wilt which occurred by Verticillium dahliae Kleb is a vascular disease in sunflower production areas in China, has not yet been effectively controlled.Therefore, in-depth to study the occurrence rule of sunflower verticillium wilt and resistance mechanism of sunflower to Verticillium dahliae will lay a solid foundation to breeding for the sunflower.This project through the biological characteristics of sunflower Verticillium dahliae; field identification, sunflower varieties which take by the breeding and seed Research lab to Verticillium wilt disease resistance; and resistance mechanisms of resistance to Verticillium wilt varieties we get the following results:1. The optimal growth temperature for the Verticillium dahliae is25℃and The optimal pH is6.0～7.0;Most suitable soil type for the growth is the loam;And when the soil moisture is less than30%,with the increase of soil moisture the faster the pathogen growth.2. The strains separated from the cotton and sunflower of Verticillium wilt, also can interaction infection the different host of cotton and sunflower.3. Watering frequency has a significant effect on Verticillium wilt severity and sunflower yield. The sunflower Verticillium wilt is seriously with the increase of the watering frequency.Severity of the disease as a significant negative correlation with the sunflower yield.4. The kind and the mount of fertilizers affected the occurrence of Verticillium wilt. In general, it can improve the sunflower resistance level to Verticillium wilt with the nitrogen or mixed nitrogen. But. to achieve the yield increas we need the ratio of fertilizer.5. Soil types have some effect to sunflower Verticillium wilt. The most serious of the sunflower to Verticillium wilt is growing in the clay soil, and the sand soil is the lightest.6. The resistance of different sunflower varieties to sunflower Verticillium wilt was tested in three different sunflower planting regions:Wuyuan of Inner Mongolia, Guyuan of Ningxia and Haerbing of Heilongjiang. Our results suggested that there not only have significant differences on the resistance to Sunflower Yellow Wilt among all the testes sunflower varieties in the same tested field, but also the same variety showed different resistance level at different tested fields. In addition, the same sunflower varieties show different resistant level in different tested sites, suggesting virulence differential do exist in Verticillium dahliae caused Sunflower Yellow Wilt.7. Different sowing dates have a significant impact to the sunflower verticillium wilt.It can reduce the sunflower verticillium wilt and ensure the yield is to on timely delayed sunflower sowing date.8. Compare the activity variation of defense enzymes using different kinds of resistant and susceptible sunflower varieties, we found that there have differences in enzyme activity due to the resistance of different varieties. The activity of defense enzyme such as PAL、PC、SOD、CAT and the content of H2O2have obviously different after inoculation.In the resistant varieties.activity of defense enzyme can make the highest increase in a short time, but the susceptible varieties always lags behind. In the resistant varieties, H2O2accumulation is faster and higher than the susceptible varieties.9. The sunflower, after infection of Verticillium dahliae, the key gene of JA path way Pr5, the key gene of SA path way upstream PAL synthesis Pal. pathogenesis-related protein gene Chit, the key gene Sco which of the formation to H2O2, the synthesis of SOD gene Sod and CAT synthetic gene Cat have in varying degrees of induced expression, the results description of SA, JA, and H2O2signaling molecules play an important role in sunflower resistance mechanim.