Genetic diversity and scope of walnut improvement in India

Abstract

Persian walnut (Juglans regia) improvement is in a primitive stage despite the fact that there exists a great amount of genetic diversity. All walnut plantations are of seedling origin. These are on an area of 35 000 hectares and produce around 20 000 MT nuts annually. About half of the produce is exported. All the seedling populations exhibit tremendous genetic variation in tree and phenological traits, colour, shell sealing and in hardness of nuts as well as quality and percentage of kernel. Therefore, systematic evaluation of this genetically diverse germplasm needs to be taken up immediately for selecting superior genotypes to build gene repository. Fortunately the selection for most of the traits, being highly heritable, can be accomplished easily. This paper considers the nature and extent of existing variation for various phenological prospects.