Winter peas have several agronomic advantages in comparison to spring pea, but the overwintering of winter peas are uncertain under the climatic conditions in Germany. Therefore, the winterhardiness of four genotypes (cvs. Assas, Cheyenne, EFB 33, Württembergische) was examined in two field trials in three growing seasons. In a first trial all peas were grown in pure and mixed stands with rye at the experimental farm of the University of Kassel and at the experimental farm of the University of Applied Sci-ence in Osnabrueck. In a second trial the impact of three sowing dates (mid of Sep-tember, end of September/begin of October and mid of October, respectively) was de-termined at the experimental farm of the University of Kassel only in pure stands.
In contrast to Assas and Cheyenne, EFB 33 and Wuerttembergische always showed sufficient winter hardiness in both trials. Consequently, a rosette growth with small leaves and short internodes at the onset of winter as well as a quantitative photoperi-odic sensitivity is required for high winter survival under the climatic conditions in Germany. Furthermore the risk of winterkill for winter peas was higher at the experi-mental site in Osnabrueck than in Kassel in two of three growing seasons due to less snow blanket in one winter and because of waterlogging as a consequence of sandy soil and unusual high precipitation in the other winter, respectively
