PISTILLATE FLOWER ABSCISSION ON FOUR WALNUT CULTIVARS
Results showed that PFA in these four cultivars was significantly different. 'AS-1' was the least affected with a PFA ratio of 2% and 'MB-T-119' had the highest proportion of PFA near 80%. In 'Hartley' and 'Serr' PFA percentage was about 50%. This relation between PFA and cultivar was also detected under natural pollination conditions.
The artificial load of pollen applied to female flowers increased significantly the percentage of PFA comparing to reference flowers (from 25% for references to 55% for artificial pollinated on average). However, 'AS-1' had in both cases the same low level of PFA.
Fruit set was also affected by the amount of pollen. A high negative correlation (>0.9) between PFA and fruit set was found.