Walnuts are naturally outcrossing species and varying degrees of dichogamy prevents self-pollination. Fruit set is generally high but flower and fruit abscission reduces the consequent yield considerably. An attempt was made to determine the extent of fruit set and retention under open, self and cross pollination in 17 germplason accessions of indigenous and exotic origin. Gobind, Plant No.10, Roopa Akhrot, Kandaghat Selection, Inder Akhrot, Plant No.32, Plant No.45, Plant No.46 and Luxmi Akhrot recorded maximum fruit set through self pollination. Blackmore, KX Giant, Rattan Akhrot, Xenia and Solding Selection recorded maximum fruit set upon cross pollination with various pollen parents. Mean fruit retention in different cultivars/selections was 52.93 per cent under open pollination, 68.02 per cent under self pollination and 64.44 per cent under cross pollination. On the whole, varietal differences for fruit set and fruit retention have been observed under each mode of pollination in the present study, except in Netar Akhrot and Plant No.47 in which it was almost at par under natural, self and cross pollination. High values of fruit retention in walnuts observed here indicates that there is little fruit drop in this species as compared to other fruit and nut species. Overall, increased fruit set under self and cross pollination suggests that walnut plantations should include either homogamous cultivars or both protandrous and protogynous cultivars to achieve adequate levels of pollination and fruit set.
