SEED YIELD IN CARAWAY (CARUM-CARVI) .1. ROLE OF POLLINATION

Seed yields of caraway vary considerably between years, indicating tha t weather affects the yield-determining processes. Pollination could b e one of these processes, because pollinator activity and efficiency a re negatively affected by cold or wet weather. From 1990 to 1992 at th e Research Institute for Agrobiology and Soil Fertility in Wageningen, The Netherlands, held and glasshouse experiments were performed to st udy the importance of pollination for caraway seed yields and the effe cts of some environmental factors. Preventing insect pollination by pl acing gauze cages in field plots reduced the yield of caraway by c. 15 -20 %, but under normal field conditions > 90 % of hermaphrodite flowe rs were fertilized and additional hand-pollination did not improve yie ld. Removal of competing umbels enhanced the low seed set percentages in higher-order umbels, indicating that pollination did not limit seed yield in these umbels. Assays suggested that wind transfer, in additi on to insects, plays a role in the pollination of caraway. It was conc luded that assimilate availability and not pollination limits caraway seed yield.