Development and Selection of Rootstocks

Abstract

The demand for the nut crops in the world has increased due to their nutritional value and economic returns. The increasing importance of nuts in healthy diet has led to the breeding work being carried out to develop and improve various scions and rootstocks to enhance the productivity and quality of nut crops. There are various challenges associated with the nut crops that make the process of improvement quite tedious and long, reducing their productivity and potential value. The development of suitable rootstocks has been found critical for solving such challenges. In this chapter, the influences of various rootstocks on the vigour of tree, quality and yield of nuts, adaptation to various biotic and abiotic stresses, disease and insect resistance, etc. have been explained. The effect of rootstock on uptake of water and nutrients that are important for growth, development of tree and have direct effect on yield of nut trees, has also been elaborated. Rootstock variability has been found to influence insect and disease sensitivity, scion precocity, fruit quality, tree size, yield at maturity, nutrient and water uptake and sensitivity to soil variables. Initially, open-pollinated seedlings, also known as seedstock, were used, but now a diverse range of clonal rootstocks have been developed through numerous rootstock breeding programmes to address critical issues such as low yield, poor nut quality, high vigour, poor soil, salinity, drought stress, suckering, diseases, graft incompatibility and climatic change. Rootstock development has potential to open up new avenues for easy propagation and genetic improvement of temperate nut crops.