Effect Of Pythium Infection On Physiological And Biochemical Indexes Of Soybean Seedling And Research In Resistance Of Soybean To Pythium

Soybean was susceptible by Pythium in the world. Pythium was the main pathogens of the diseasesoybean root rot. It mainly infected unerupted seed in the soil, the hypocotyls and root before the seedemergence and the apical and nutritive root after the seed emergence. It causes the seeds to rot, theseeding lodging befor and after seedling emergence, et al. According to the seed decay test method, thisexperiment made the identification of soybean varieties for the resistance of Pythium. Physiological andbiochemical indexes change of soybean hypocotyls after soybean seeding of the resistant varieties andsusceptible varieties inoculation Pythium was studied. The resistance effect of the physiological andbiochemical index between the interaction of soybean and Pythium was studied.The results as:1. Identification of resistance of soybean to PythiumThe experiment used seed decay test method on common soybean cultivars for resistance toPythium identification. The results show that Dongnong47, Heihe38, Kangxian5and Kangxian3showed high susceptibility for Pythium. Hefeng52andSui07-361performed moderate susceptibility onPythium. The Huibuzhiheidou, Nenfeng16、Zooplankton abundance19、Heinong55manifested diseaseresistance on Pythium.2. Effect of Pythium infection on physiological and biochemical indexes of soybean seedlingAfter inoculation Pythium, the lateral root number, cotyledons of dry matter content, radicle of drymatter content and root cap of the resistant and susceptible soybean varieties was less than the controlsample.The reduced amplitude of the ratio of the lateral root number, cotyledons of dry matter content,radicle of dry matter content and root cap of the resistant soybean varieties is significantly smaller thanthe susceptible cultivar.Early infection Pythium, the content of the PAL activity, chitinase activity, totalphenolics content, and flavonoids content in resistant varieties rises quickly, but the content ofsusceptible varieties rises slowly. The peak of PAL activity, chitinase activity, total phenolics content,and flavonoids content of the disease resistant varieties was higher than that of susceptible varieties.ThePOD activity, soluble sugar content in resistant varieties with the extend of the inoculation time showsrapid upward trend. The POD peak of the disease resistant varieties was higher than that of susceptiblevarieties, but the content of susceptible varieties rises slowly. After the infection of Pythium, the prolineand MDA content of the disease resistant varieties was significantly less than that in susceptiblecultivars.3. Selection of the best parent crosses on the differences resistance to PythiumThe maximum correlation of the ideal reference and Heinong55was0.925. The relevance rankingof other types in turn is Nenfeng19, Nenfeng16, Kangxian3, Dongnong47, and Kangxian5. Thisexperiment selects Heinong55and Kangxian5as the resistant and susceptible hybrid crosses that markedby the resistance to Pythium gene molecular.The DNA of resistant Heinong55and susceptibleKangxian5exists polymorphism, and polymorphic primers frequency is16%.