Effect of Copper Oxychloride and Volck® Mineral Oil on Blooming Time, Frost Resistance and Yield in Almond cv. “Mamaei”

Almond [Prunus dulcis (Mill.) D.A. Webb] is one of the most important cultivated fruit trees in Iran. Late frost in spring is a key limiting factor for almond productivity given that almond trees flower early in the spring in comparison with other temperate fruit trees. To decrease frost injury in “Mamaei” cultivar, this study was carried out in factorial randomized complete block design (CRBD) with four replications. Almond trees were sprayed with 5%, 10% and 15% concentrations of Volck® mineral oil mixed with a constant 3 g.l-1 concentration of Copper Oxychloride at two separate times, before swelling bud stage and at the swelling bud stage. The control almond trees were sprayed with pure water. The parameters such as phenological development stages of flower bud, amount of frost injury, bud abortion, fruit set and yield were measured. The results indicated that the trees treated with Copper Oxychloride and Volck® mineral oil did not show significant effects on blooming time but had a significant effect on other parameters. The result of the mean comparison indicated that the highest percentage of bud abortion (1.84%) occurred by using 15% oil concentration and the lowest bud abortion (0.49%) occurred in the control trees. The highest yield (7.9 kg/tree) was achieved by the use of 5% Volck® mineral oil plus 3 g.l-1 Copper  Oxychloride during the swelling bud stage.