Phenological development - Yield relationships in dry pea in semiarid Mediterranean conditions

Dry pea (Pisum sativum, L.) growers in the semiarid Mediterranean region re quire cultivars that are both early maturing and high yielding. However, ne gative relationships between these two characteristics limit their simultan eous improvement. A better understanding of the relative importance of the developmental stages in determining yield would assist in pea improvement. Sixteen dry pea cultivars were grown for 2 years under semiarid Mediterrane an conditions (Maru, north Jordan) in order to see if differences in growin g degree days (GDD) to flowering and GDD from planting to physiological mat urity exist and to study their relationships with seed yield. Seed yield wa s negatively correlated with GDD to maturity, but not significantly correla ted with GDD to flowering. Increasing GDD to flowering resulted in higher s eed yield, while increasing seed fill duration had little effect.. Rapid se ed fill rate was positively correlated with seed weight and negatively corr elated with seed fill duration. These results indicate that Mediterranean-a dapted cultivars would have preflowering periods lasting as long as possibl e, followed by short seedfill periods. Simultaneous selection for early mat urity and a relatively long time to flowering is recommended for the develo pment of early-maturing, high-yielding cultivars adapted to semiarid Medite rranean environments.