Improving the forage and grain yields and the yield stability of field peas in semi-arid areas in Morocco

Field peas (Pisum arvense L.) would be a suitable protein resource to improve livestock feeding in semi-arid areas; however, green feed and seed yields are low and unstable in these environments. The variability of the yields of seven field pea cultivars over the seasons under rain-fed conditions highlighted the effect of the climate. The aim of this study was to optimize and stabilize field pea yields in contrasting climatic environments through a strategy of cultivar adaptation. The genotype x environment interaction was significant and the stability analysis showed which were the most performing cultivars in such climatic environments. Those with the best mean performance and stability were V3, V5 and V6 for dry matter, and V1, V4 and V5 for seed yield. The cultivar V6 had a wide adaptability in terms of dry matter, whereas V3 and V5 were particularly adapted to favourable and unfavourable environments respectively. Regarding seed yield however, V1 and V4 were more productive in favourable environments, and V5 in unfavourable ones. The genetic gain was significant : in comparison to V7, V5 had a wider adaptability for both dry matter and seed yield; it has been registered in the Moroccan official cultivar list under the name Ezzahra. The most critical period for field pea growth occurs from the beginning of flowering to green seeds. Cold during that period reduced seed yield by half, and by 75% when associated with water stress during pod setting.