Effect of rootstocks and soil management on growth and physiological parameters in new plantations of apple under replant conditions

Abstract

Apple orchards planted in late sixties in Himanchal Pradesh and North Western Himalayan region have shown symptoms of declining productivity as these plants have completed their economic life span. Due to limited land and choice of crops for smaller micro climatic niches and incomparable economic equivalence of other fruits with apple, orchardists are compelled to replant at old apple orchard sites. Standardization of suitable agro-techniques to combat replant problem in apple for better field survival rate and productivity is required to sustain apple industry in the state. In the present study, there were 20 treatments comprising of four apple rootstocks i.e. seedling, M793, MM111 and M7 and five different soil management treatments i.e. control, soil fumigation, Plant growth promoting rhizobacteria (PGPR), biocontrol and combined soil fumigation + PGPR + Biocontrol with three replications. The pooled data over the years 2015 and 2016 revealed that M793 rootstock had the maximum growth, vigour, chlorophyll content and photosynthetic efficiency. Among the soil management treatments, the highest growth and vigour parameters, chlorophyll content and photosynthetic efficiency were recorded maximum in combined treatment. The interaction between rootstocks and treatments revealed that combinations of M793 and combined treatment resulted the maximum growth and vigour traits, chlorophyll content, rate of photosynthesis, transpiration rate, stomatal conductance, water use efficiency and minimum stomatal resistance compared to other rootstocks and treatment combinations under replant situations, which can be exploited for the management of replant problem in apple.