Adapting soya to Swiss climate conditions is a priority for Agroscope. Only varieties that are well-adapted to local conditions will secure stable and satisfactory returns for the farmer. The soya bean is native to north-eastern China so is poorly suited to climate conditions north of the Alps. Early genotypes which are not photoperiod-sensitive are best suited to Switzerland. Large-leaved plants are more prone to lodging. The shaded lower leaves have an undesirable negative photosynthesis balance. Soya is very sensitive to cool temperatures during the flowering period. Repeated spells of cold weather can cause extensive flower dropping and even small pods, which reduces yields and delays maturity. The resulting difficult harvest can lead in extreme cases to a partial or even complete loss of the crop. Choosing early, small-leaved and cold-resistant lines is therefore essential.