Harvest management in walnuts by USF of ethephon (2-Chloroethyl phosphonic Acid)

Ethephon was sprayed (Pre harvest treatment) on young bearing walnut trees at packing tissue turned brown (PTB) stage and as dip treatment (Post harvest) on walnuts plucked at PTB stage, with a view to see if the treatments brought about earlier hull dehiscence which is a desirable feature for maintainng colour and quality of walnuts. Ethephon was used at the concentration of 500, 1000, 1500 and 2000 ppm. The spray treatment brought about early dehiscence of walnuts and at the highest dose, the hull dehiscence time was reduced to about half of control (From 28 to 17 days). The Post harvest dip treatment also reduced the dehulling time, with the highest concentration reducing it by half of that in control (From 13 to 6 days). In view of the short period taken for dehulling in harvested walnuts and its further reduction by ethephon, the post harvest dip treatment has been considered to be of commercial applicability.