核盘菌对油菜、向日葵和大豆的侵染及其致病性分化研究

Infection of Sclerotinia sclerotiorum to rapeseed, soybean and sunflower and its virulence differentiation

通过对从陕西大荔采集的油菜及其后茬向日葵上的核盘菌和从新疆阿勒泰的向日葵上采集的核盘菌样品进行单菌 核分离、培养和纯化,比较其菌丝生长速度、菌丝干重、菌落形态、致病力强弱及菌株的草酸累积等,将两地的核盘菌分成 A、B、C三种类型,其中A类来源于陕西大荔的油菜和向日葵,B、C类来源于新疆阿勒泰的向日葵。不同类型核盘菌对于 不同寄主的致病力存在着分化现象,A、B类菌株生长正常、菌落均匀旺盛,B类对油菜、向日葵和大豆的致病力较强,草酸 产量较高;而A类仅对油菜和向日葵的致病力较强对大豆的致病力很弱,但草酸产量最高。C类菌株生长异常,菌落稀疏 不均匀,对3种作物的致病力均弱,草酸产量较低。2001年田问调查亦表明:A类菌株可导致油菜、向日葵菌核病的发生, 但未见其使大豆致病,由此提出油菜茬后,不宜种植向日葵,二者应与小麦、玉米等实行较长周期的轮作。本文也同时对各 菌株进行了RAPD分析和菌丝体亲和性研究,结果表明,菌株间的遗传多样性表现丰富但未发现与其致病性分化相关。

Isolation, culture and purify of single-sclerotium of S. sclerotiorum from rapeseed and sunflower in Dali county of Shaanxi province, as well as S. sclerotiorum of sunflower from Aletai, Xinjiang province. The isolates were divided into three types： A, B and C, according to the growth rate and the dry weight of mycelium, the characteristic of colony, pathogenicity and oxalic acid accumulation. Type A was from rapeseed and sunflower in Dali county of Shaanxi province, and types B and C from sunflower in Aletai of Xinjiang province. The study showed that the virulence of S. sclerotiorum on different hosts was different. Growth of types A and B was normal, and their colonys were even and vigorous. The virulence of type B was stronger on rapeseed, sunflower and soybean, and yield of its oxalic acid was higher, and the virulence of type A was strong only on rapeseed and sunflower, and it was very weak on soybean, but yield of its oxalic acid was the highest. The growth of type C was abnormal, its colony was rare and not even, and its virulence was weak on all three crops, and the yield of its oxalic acid was lower. In 2001, the field investigation showed that type A isolates resulted in Sclerotinia stem rot, not only on rapeseed but also on sunflower （ root rot type）, but it was not found on soybean. So it was not suitable for growing sunflower in afterreap field of rapeseed, and rapeseed or sunflower should shift to grow with wheat, maize for crop rotation. The RAPD analysis and compatibility test were utilized to further investigation. It was found there were no correlation between the genetic diversity there existed genetic diversity in searched isolates, but and virulence differentiation.