Koski Tuuli-Marjaana, de Jong Sanne, Muola Anne, Amby Daniel B, Andreasson Erik, Stenberg Johan A
Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp, Sweden.
Section of Ecology, Department of Biology, University of Turku, Turku, Finland.
Front Plant Sci. 2021 Sep 23;12:722795. doi: 10.3389/fpls.2021.722795. eCollection 2021.
The transition toward more sustainable plant protection with reduced pesticide use is difficult, because there is no "silver bullet" available among nonchemical tools. Integrating several plant protection approaches may thus be needed for efficient pest management. Recently, increasing the genetic diversity of plantations cultivar mixing has been proposed as a possible method to reduce pest damage. However, previous studies have not addressed either the relative efficiency of exploiting cultivar mixing and intrinsic plant herbivore resistance or the potential utility of combining these approaches to increase cropping security. Here, using a full factorial experiment with 60 woodland strawberry plots, we tested for the relative and combined effect of cultivar mixing and intrinsic plant resistance on herbivore damage and yield. The experiment comprised two levels of diversity ("high" with 10 varieties and "low" with two varieties) and three levels of resistance ("resistant" comprising only varieties intrinsically resistant against strawberry leaf beetle ; "susceptible" with susceptible varieties only; and "resistance mixtures" with 50:50 mixtures of resistant and susceptible varieties). The experiment was carried out over two growing seasons. Use of resistant varieties either alone or intermixed with susceptible varieties in "resistance mixtures" reduced insect herbivory. Interestingly, resistant varieties not only reduced the mean damage in "resistance mixtures" by themselves being less damaged, but also protected intermixed susceptible varieties associational resistance. The effect of higher genetic diversity was less evident, reducing herbivory only at the highest level of herbivore damage. In general, herbivory was lowest in plots with high diversity that included at least some resistant varieties and highest in low diversity plots consisting only of susceptible varieties. Despite this, no significant difference in yield (fruit biomass) was found, indicating that strawberry may be relatively tolerant. Our results demonstrate that combined use of high genetic diversity and resistant varieties can help reduce pest damage and provide a useful tool for sustainable food production. "Resistance mixtures" may be particularly useful for sensitive food crops where susceptible varieties are high yielding that could not be completely replaced by resistant ones.
向减少农药使用的更可持续植物保护方式转变困难重重，因为在非化学工具中没有“万灵药”。因此，可能需要整合多种植物保护方法来进行有效的害虫管理。最近，增加种植园的遗传多样性（品种混合）已被提议作为一种减少害虫损害的可能方法。然而，以前的研究既没有探讨利用品种混合和植物固有抗虫性的相对效率，也没有涉及将这些方法结合起来提高作物安全性的潜在效用。在这里，我们使用了一个包含60个林地草莓地块的全因子实验，测试了品种混合和植物固有抗性对食草动物损害和产量的相对及综合影响。该实验包括两个多样性水平（“高”有10个品种，“低”有2个品种）和三个抗性水平（“抗性”仅包括对草莓叶甲具有固有抗性的品种；“易感”仅为易感品种；以及“抗性混合物”，抗性和易感品种各占50%）。实验在两个生长季节进行。单独使用抗性品种或在“抗性混合物”中与易感品种混合使用均可减少昆虫食草作用。有趣的是，抗性品种不仅自身受损较少从而降低了“抗性混合物”中的平均损害，还保护了混合种植的易感品种（关联抗性）。较高遗传多样性的效果不太明显，仅在食草动物损害最高水平时才减少了食草作用。总体而言，在具有高多样性且至少包含一些抗性品种的地块中食草作用最低，而在仅由易感品种组成的低多样性地块中食草作用最高。尽管如此，产量（果实生物量）没有显著差异，这表明草莓可能具有相对耐受性。我们的结果表明，高遗传多样性和抗性品种的联合使用有助于减少害虫损害，并为可持续粮食生产提供了一个有用的工具。“抗性混合物”对于敏感粮食作物可能特别有用，因为易感品种高产，无法完全被抗性品种取代。
