The diversity of varieties is the first factor that allows adaptability of the system according to its production capacities and desired destinations. The aim of this trial is to characterize the tolerance of each variety to water stress and thus refine agronomic recommendations to be made to producers and industrialists.
Effect of irrigation: a generalized but differentiated decrease
The analysis of the results highlights an almost systematic decrease in yield under non-irrigated conditions. This observation confirms the major impact of water deficit on potato crops, particularly during tuberization and enlargement phases.
However, beyond this overall trend, the amplitude of the decrease varies significantly depending on genotypes (varieties). This genotype-water regime interaction reflects a diversity of physiological responses from the varieties to stress: water efficiency, maintenance of photosynthetic activity, limitation of tuber abortion, etc.
Typology of varietal behaviors
The analysis allows for the distinction of three main profiles:
1. Varieties tolerant to water stress (DB-649-16-3, Palace, Theda, Storm, Lady Avalon, and Travis)
These varieties either have a high yield level under non-irrigated conditions or a limited irrigated/dry differential. They combine stability and relative performance, suggesting good water use efficiency. Their positioning above or near average under dry conditions makes them references for constrained irrigation systems.
2. Varieties sensitive to water stress (Honorata, Gravity, Valencia, Norman, and Leonore)
These varieties record low yields in dry conditions (around 5.5 to 7.5 t MS/ha), indicating a strong dependence on irrigation. Their performance decline indicates a marked sensitivity to water deficits, possibly linked to a lesser stomatal regulation capacity or a less exploratory root system.
3. Varieties with high potential but unstable (Esperanto, Lady Jane, and Carlos)
These profiles are characterized by high yields under irrigated conditions but a significant degradation in dry conditions. Their genetic potential is real but strongly conditioned by water availability, making them primarily intended for irrigated contexts.
Focus on dry matter: a discriminating criterion
In addition to overall yield, the ability to produce dry matter is a determining factor for processing chains. In this regard, some varieties stand out clearly, especially DB-649-16-3 and Lady Avalon, which combine a good level of dry matter and tolerance to stress.
Notable fact: Norman also shows a good ability to produce dry matter despite its sensitivity to water deficits. This emphasizes the importance of crossing criteria (yield, stability, quality) in variety selection.
Agronomic lessons and recommendations
This trial highlights several key points:
– Water stress systematically impacts yield, but with an intensity dependent on genotype. – Varietal variability is pronounced enough to serve as an agronomic adaptation lever. – Variety selection should be reasoned based on irrigation capacity and production objectives (yield vs dry matter). – In limiting water conditions: favor DB-649-16-3, Palace, Theda, Storm, Lady Avalon. – In irrigated systems: the potential for high-value varieties like Esperanto, Lady Jane, or Carlos can be leveraged. – For industrial outlets: integrate the dry matter criterion into variety selection decisions.
Conclusion
In a climate change context, this trial confirms the strategic importance of varietal selection as an adaptation lever. Identifying tolerant and stable profiles is a major asset for securing productions, especially in areas where access to irrigation becomes limiting.
However, it is important to consider the destination of the produced tubers before choosing the variety. These varieties have different responses to processing. Yield is not the only parameter to consider.
