Physiological parameters that contribute to Kernel Shrivel in walnuts

Abstract

The Walnut tree (Juglans regia L.) is one of the most consumed nut species that has been gaining importance with the implementation of new orchards from north to south of the country. The incomplete formation of the seed (Kernel Shrivel) is one of the problems that most depreciates the quality and for which there isn’t an effective control due to its unknown origin. The accumulation of seed reserves that result in the development of the seed tissues, depends on several factors associated with the tree's physiology. To understand the origin of this physiological anomaly in the walnuts, several parameters were evaluated: nutrient, fiber, fat and starch content in the branches. It was found that starch content in the branches seems to be the parameter that is most correlated with Kernel shrivel, with the less vigorous varieties (Lara and Howard) having a higher starch content and apparently a lower predisposition to the occurrence of this disorder. As these varieties have a lower percentage of shriveled kernels and are also less vigorous, there seems to be a correlation between the level of radiation received and the development of the seed. Thus, the higher level of radiation absorbed by these trees, may contribute to the lower predisposition of Kernel Shrivel.