SEASONAL CHANGES OF NUTRIMENTS IN LEAVES AND FRUIT DROP OF ‘CRIOLLO’ PEACH IN ZACATECAS, MÉXICO

Abstract

Fruit drop is a constant concern among criollo peach (Prunus persica L. Batsch) growers, and it has not been evaluated at the main growing areas in Zacatecas, México. The relationship between fruit drop and nutritional status of native peach trees with different irrigation program, soil type, planting densities, and pruning program was studied. The experiment was conducted over two consecutive growing seasons 1997-1998 and 1998-1999, in three commercial orchards: Campo Experimental Zacatecas, Mesa de Fuentes, and San José de Félix. Ten 8 to 10-year-old trees were randomly selected and four fruiting shoots of similar length and fruit number were tagged
around the canopy of each tree. Percent of fruit drop was recorded on 65, 113, 147, 166, and 181 d after full bloom. At the same time, foliar concentration of macro and micronutriments and vegetative and reproductive growth of each tree, were recorded. In 1998 fruit drop and fruit set did not differ among orchards and there was no
correlation between fruit drop and foliar concentration of nitrogen, boron, and calcium. Air temperature after endodormancy, in terms of growing degree days, explained 56 % of fruit drop. On the average, a 36 % of fruit set was registered, which can be considered sufficient for a commercial yield.