THE PREVALENCE OF VERTICILLIUM WILT IN OILSEED RAPE IN LITHUANIA

摘要

Oilseed rape (winter and spring) is the second largest crop after winter wheat grown in Lithuania. Apart from the most devastating diseases such as Sclerotinia, blackleg and black spot, Verticillium wilt, whose severe outbreak was first recorded in 2008, has become a major challenge in winter oilseed rape (WOSR) and spring oilseed rape (SOSR) production. To tackle this problem, our study was aimed to ascertain the differences in the susceptibility of WOSR and SOSR cultivars to Verticillium wilt. A total of 16 oilseed rape cultivars (8 WOSR and 8 SOSR) were tested for the incidence and severity of Verticillium wilt as well as for their seed yield. Field experiments were carried out at the Institute of Agriculture, Lithuanian Research Center for Agriculture and Forestry over the two growing seasons - 2013/2014 and 2014/2015. The results of the current study revealed that the mean incidence of Verticillium wilt for WOSR ranged from 29.1 to 53.1%, while for SOSR it varied from 27.8 to 66.6%. Significant differences in susceptibility to Verticillium wilt were estimated among the WORS and SOSR cultivars. The lowest disease severity was determined for Kolumb (WOSR cultivar) and Kaliber (SOSR cultivar) (P <0.001), while the highest disease seventy was estimated for Nelson (WORS cultivar) and Mirakel (SOSR cultivar) (P < 0.001). During the first growing season, six cultivars out of eight showed higher seed yield compared to the mean seed yield for both WOSR and SOSR. Meanwhile, during the second growing season four out of eight WOSR and SOSR cultivars exhibited higher seed yield than the mean.