Combining a multi-environment trial and a diagnosis method to assess potential yield and main limiting factors of three highly different pea types

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The evaluation of varieties of cultivated species is based on the implementation of multi-environmental trials that show high performances or strong limitations in some environments. To know the cause of these limitations, and to reason the adaptation of varieties to different environments, we propose a combined approach between the classical analysis of experimental results and a diagnostic approach using the DiagVar tool, which allows to assess the impact of limiting factors in each trial, the potential yield and the sensitivity of cultivars to those factors. This procedure is applied in a large and diversified field trial network including eight locations and three years to the comparison of two to four cultivars of the three agronomical pea types: spring peas, hr-winter peas (non-reactive to photoperiod) and Hr-winter peas (reactive to photoperiod).Estimates of potential yields from DiagVar for the three pea types were consistent with the experimental results, with higher values for hr-winter cultivars than for spring and Hr-winter ones. We shed light on specific limiting factors for each type, some of them being rarely quantified previously, which allows us to better target specific regions or environments for each pea type. Thus, spring types were more impacted by early limiting factors (loss of plants, low temperatures and radiation, lack of water, leading to reduced growth) and end-of-cycle stresses (high temperatures, water stress). Diseases had higher impacts on both winter types. Here we show for the first time that the lack of solar radiation affected particularly hr-winter type and the low crop nitrogen status affected more frequently spring peas. These results highlight the interest of carrying out an agronomic diagnosis in the analysis of varietal multi-environment trials, revealing the most important limiting factors to take into account while breeding new pea cultivars, particularly limiting factors that are difficult to directly observe. This method proves to be reliable and informative for breeders, technicians and agricultural advisors to discuss the adaptation of varieties to specific environment.