Breeding strategy for faba bean in southern Europe based on cultivar responses across climatically contrasting environments

Expanding grain legume cropping is desirable but is hindered by low yields. Seventeen faba bean (Vicia faba L.) cultivars belonging to four germplasm types - Mediterranean (from Sicily or Syria), semi-Mediterranean (from continental Italy or Spain), winter, and spring (from France or Germany) - were grown in two climatically contrasting sites (Lodi, subcontinental; Foggia, Mediterranean), two years per site and two sowing times per year, to support breeding strategies by assessing genotype x environment (GE) interactions and their relationship with spatial and temporal factors, germplasm type, and morphophysiological traits. Crossover GE interaction was large and mainly due to the geoclimatic area and the germplasm type. Additive main effects and multiplicative interaction modeling showed (i) the superiority of Mediterranean material across Foggia's environments (all autumn sown), (ii) a trend toward better performance of winter germplasm in Lodi under autumn sowing, and (iii) the similar performance of winter, spring, and semi-Mediterranean types in Lodi under late-winter sowing. Adaptation to each site was related to different and partly incompatible traits, owing mainly to site-specific optima of earliness of cycle and stress tolerance. The results support the specific breeding for each geoclimatic area based on distinct genetic bases and selection environments. © Crop Science Society of America. All rights reserved.