Differences in drought tolerance in almond cultivars grown in Apulia region (Southeast Italy)

Almond (Prunus amygdalus Batsch) is considered to be able to tolerate drought stress fairly well during all stages of fruit growth. Nevertheless, severe water stress together with high temperatures during summer can seriously reduce hull split and consequently promote the occurrence of hull-tight nuts. In this study we report the results of an investigation carried out in Apulia region (Southeast Italy) in order to evaluate the effects of the long, dry and warm 2012 summer on fruit quality of 23 almond cultivars. Cultivar sensitivity to water stress was expressed as hull-tight nut percentage. At harvest, the following measurements were performed: hull-tight nut percentage, kernel weight, percentage of well filled, empty and wrinkled kernels, both on normal and hull-tight nuts. Almost all cultivars showed fruits with adhering hulls, but with significantly different incidence. On average, hull-tight nuts showed lower kernel weight and higher percentage of empty and wrinkled kernels than normal fruits which, however, showed kernel weight values lower than those observed in standard years.