Studies on effect of rootstocks on root distribution pattern of cashew

Abstract

The present investigation on the root distribution pattern of cashew rootstocks was carried out at ICAR-Directorate of Cashew Research (DCR), Experimental Station, Santhigodu, Karnataka. The study aimed to understand the root distribution of two dwarfing rootstocks (NRC 492, Taliparamba-1) and one vigorous rootstock (Vengurla-4) of eight-years-oldcashew tree, as determined by the root excavation method. The root samples were collected vertically from different depths (0-200 cm) and laterally at different distances (0-300 cm) from the tree trunk. Results indicated that the root distribution pattern showed significant genotypic variation. Regarding the vertical distribution of roots, 95 percent of the roots were distributed in 0-100 cm horizons, while very few roots were in the 100-200 cm horizons. In the lateral distribution, 97 percent of root density was in the 0-200 cm area from the tree trunk. Vengurla-4 (vigorous rootstock) had a higher root length, root volume and two-fold increases in total root production compared to dwarf rootstocks. PCA study revealed that the selection of rootstocks based on tree height, TCSA, canopy spread, lateral and vertical distribution of roots represent the main morphological indices for evaluating the effect of cashew rootstocks.