河北省禾谷孢囊线虫种群密度和冬小麦产量损失的关系

为明确禾谷孢囊线虫Heterodera avenae对小麦的危害,于2011年10月—2012年6月在自然环境条件下采用定量接种方法测定了其在不同接种密度下对冬小麦产量和线虫繁殖的影响。结果表明,随着禾谷孢囊线虫接种密度的增加,小麦的株高、穗长、小穗数、分蘖数和籽粒重均呈下降趋势。小麦产量随着接种密度的增加损失率增加,在接种密度大于29个卵和2龄幼虫/g土时,小麦产量损失率均达50%以上,接种密度为465个卵和2龄幼虫/g土时损失率最大,达到77.7%;当接种密度小于116个卵和2龄幼虫/g土时,禾谷孢囊线虫的最终密度随着接种密度的增加而增加,但接种密度大于该值时,最终线虫密度则随着接种密度的增加而减少;且其繁殖系数随着接种密度的增加而降低。以小麦单株籽粒重为参数,利用Seinhorst模型拟合孢囊线虫密度与产量的关系,可知小麦对禾谷孢囊线虫的最低忍耐值为5个卵和2龄幼虫/g土,相对最低产量为0.23。

Relationships between population densities of the cereal cyst nematode, Heterodera avenae, and yield losses of winter wheat in Hebei Province

The effects of the cereal cyst nematode, Heterodera avenae, density on wheat yield loss and reproduction of nematodes were evaluated under natural conditions in pots by using inoculating quantitatively method from October 2011 to June 2012 for understanding the damage of the nematodes to winter wheat. The plant height, length of spike, number of spikelets, number of tillers and grain weight decreased with increasing density of nematodes inoculated. Wheat yield loss was more than 50% when the initial population of nematodes (P_i) was higher than 29 eggs and second-stage juveniles (J2)/g soil, while it reached to 77.7% when P_i was 465. The final population (P_f) of H.avenae increased with increasing P_i when the nematode density was less than 116 eggs and J2/g soil, while P_f decreased with the increasing P_i when P_i were higher than 116 eggs and J2/g soil. The reproduction rate of nematodes decreased with increasing P_i. The Seinhorst equation was used to model the relation between the yield of winter wheat and P_i by using the parameter of grain weight, and the tolerance limit of wheat to the nematodes was 5 eggs and J2/g soil and the minimum relative yield was 0.23.