Cultivar mixture effects on disease and yield remain despite diversity in wheat height and earliness

Abstract

Cultivar mixtures can stabilize yield and reduce pathogen spread in plant populations. A field experiment was performed to determine whether (i) a large difference between the cultivars in the mixture (e.g. plant height or earliness) would have an impact on mixture performance and whether (ii) such differences would modify the classical rules for mixture design. Mixtures were constituted from cultivars with diversity for many traits, including plant height, flowering date, disease resistance and yield potential. The field experiment was conducted in three years testing each year 72 to 90 mixtures of two, four or eight cultivars, and their corresponding pure stands. Disease severity and yield of cultivar mixtures were strongly related to the mean values of the component cultivars in pure stands. Despite the considerable diversity of the mixtures tested, the classic rules (e.g. proportion of susceptible cultivars) already tested in mixtures with similar height and earliness were effective for decreasing disease severity. Agronomic heterogeneity for traits such as plant height, yield potential or earliness of the cultivars in mixtures did not have a negative impact on disease severity and yield relative to pure stands. Increasing the number of cultivars in the mixture from two to eight had no impact on the mean disease severity and yield of the mixtures, but reduced the variability of disease severity and yield in the mixture relative to pure stands. These results suggest that it may be possible to increase within-field wheat diversity by combining more contrasted cultivars in mixtures than was previously thought.

Winter Wheat Mixtures Influence Grain Rheological and Mixolab Quality

“…A complementary solution may be the development of alternative farming methods. Mixtures of cultivars may help to stabilize yields and increase the quality of wheat (Ceseviciene et al, 2009;Konvalina et al, 2009;Vrtilek et al, 2016;Vidal et al, 2020;Lacko-Bartošová et al, 2021).…”

“…Environmental friendliness is another benefit that should not be overlooked. Parallel planting of two winter wheat varieties that complement each other in traits such as high and low tolerance to frost, drought, diseases, and lodging boosts the inter-annual stability of yields and quality of output (Vrtilek et al, 2016;Vidal et al, 2020).…”

The impact of wheat cultivar mixtures on virulence dynamics in Zymoseptoria tritici populations persists after interseason sexual reproduction

“…This study provides experimental elements for further investigation, by modelling approaches, of the potential of cultivar mixtures as a durable resistance deployment strategy relative to other strategies, as assessed by Rimbaud et al (2018), for example. In estimations of the impact of key factors, it will be crucial to consider the nature and number of resistance genes, the proportion of each cultivar in the mixture and the frequency of virulences (and their combination, if any) in the local population (Kristoffersen et al, 2021; Vidal et al, 2020). An understanding of the interactions between these factors will clearly require modelling approaches, but also further experimental fungal biology studies in semicontrolled conditions (e.g., Orellana‐Torrejon et al, 2022b) to characterize the abovementioned mechanisms in greater detail.…”

Does the impact of cultivar mixtures on virulence dynamics in Zymoseptoria tritici populations persist after interseason sexual reproduction?

“…This study provides experimental elements for further investigation, by modelling approaches, of the potential of cultivar mixtures as a durable resistance deployment strategy relative to other strategies, as assessed by Rimbaud et al(2018), for example. In estimations of the impact of key factors, it will be crucial to consider the nature and number of resistance genes, the proportion of each cultivar in the mixture, and the frequency of virulences (and their combination, if any) in the local population (Vidal et al, 2020;Kristoffersen et al, 2021). An understanding of the interactions between these factors will clearly require modelling approaches, but also further experimental fungal biology studies in controlled conditions to characterise the abovementioned mechanisms in greater detail.…”