Agriculture Victoria, Horsham, Victoria, Australia 3401.
Statistics for the Australian Grains Industry-West, Curtin University, Bentley, Western Australia, Australia 6102.
Phytopathology. 2020 Mar;110(3):674-683. doi: 10.1094/PHYTO-08-19-0320-R. Epub 2020 Feb 4.
The root lesion nematode causes economic losses in wheat and barley internationally through both reduced grain yield and grain quality. This study investigated the relationships between the presowing density and grain yield and the postharvest nematode densities. Four field experiments were conducted at the same site between 2010 and 2014. A range of presowing densities was established in the first year by growing three cereal cultivars that ranged from resistant to susceptible. In the following year, plots were sown with the five same cereal cultivars. A linear relationship was observed between the natural log of the presowing density and grain yield across all seasons. The results showed that grain yield losses varied between cultivars and seasons. The importance of season was significant, with this study conducted over several seasons, and it highlighted the variability in yield losses between seasons, which will need further investigation. The greatest yield losses observed were 25 to 28% when the maximum presowing densities ranged between 150 and 250 g of soil. An analysis of the relationship between the presowing and postharvest nematode densities revealed that increased presowing nematode densities resulted in decreased multiplication rates in all seasons and in all cultivars. Nematode multiplication rates also varied between seasons. These results explain why it is difficult to predict nematode levels based on cropping history, and additionally, they highlight the importance of growing resistant cultivars to maintain low levels of to minimize risk of yield losses.
根结线虫通过降低小麦和大麦的籽粒产量和品质，在国际上造成了经济损失。本研究调查了播前密度与籽粒产量和收获后线虫密度之间的关系。2010 年至 2014 年在同一地点进行了四项田间试验。在第一年，通过种植三种从抗到感的谷物品种，建立了一系列播前密度。次年，用相同的五种谷物品种播种。在所有季节，播前密度的自然对数与籽粒产量之间存在线性关系。结果表明，籽粒产量损失在品种和季节之间存在差异。季节的重要性很显著，本研究在多个季节进行，突出了季节之间产量损失的可变性，这需要进一步调查。当最大播前密度在 150 至 250 克土壤之间时，观察到的最大产量损失为 25%至 28%。播前和收获后线虫密度之间关系的分析表明，所有季节和所有品种的播前线虫密度增加都会导致繁殖率降低。线虫繁殖率也因季节而异。这些结果解释了为什么根据种植历史很难预测线虫水平，此外，它们还强调了种植抗性品种以保持低水平以最小化产量损失风险的重要性。
