The Influence of Dwarfing Interstock on Biometric Growth Parameters of Apple

Abstract

Apple trees grown on seedling rootstock often develop into large and vigorous trees making its management difficult. By using vigorous rootstocks only few trees can be accommodated per hectare making the productivity less profitable. Several dwarfing rootstocks of apple are available which need support system and incur heavy investment during orchard establishment.  It would be ideal to obtain a tree with very good root system, to avoid the need for supporting systems and also with a low height, which can be achieved using the interstem. Therefore, in the present investigation M9 clonal interstem comprised of 2,4,6 and 8inches length were grafted between seedling rootstock and scion of two  cultivars i.e., Red Delicious and American Apirouge which are most common and predominant cultivars in orchards of Kashmir. The average sapling height was to the tune of 38.85cm and 41.01 cm in Red Delicious and American Apirouge during first year of study. There was a progressive increase in the height of plant with decreasing interstem length. In both the apple cultivars  stem diameter increased with decrease in interstem length but was lower than control during both the years of study, The rootstock influences the biometric parameters of the grafted trees. The results showed that increased interstem length significantly decreased sapling height and growth whereas, days taken to sprouting and survival per cent were non significant. Thus, it appeared as if the dwarfing rootstock genotype used as an inter-stem functioned as  a kind of physical restriction to water movement and probably reduced the hydraulic conductance  of the whole tree.