Importance of PAR interception and radiation use efficiency on growth and yield of Potatoes under different microclimates in the upper Brahmaputra valley zone of Assam

Abstract

A field experiment was conducted at Assam Agricultural University, Jorhat, Assam, during rabi 2018-19 to assess the PAR interception and radiation use efficiency in potato variety Kufri Jyoti under different microclimates, which was planted in split plot design with four dates of plantings starting from 10 November (P1) at ten days interval and three mulching treatments, viz., water hyacinth, black polythene and without mulching. The incident, reflected and transmitted PAR was measured periodically over the crop with a line quantum sensor and daily incident radiation was calculated from incident PAR and bright sunshine hours. The interception of PAR (iPAR) varied considerably among different treatments, while the highest iPAR was recorded under the first date of planting and mulching treatment with water hyacinth. The leaf area index (LAI) and biomass production were highest in crops planted on first planting date with water hyacinth mulch. The RUE for tuber yield was highest in water hyacinth (2.35 g MJ-1) followed by black polythene (2.03 g MJ-1) and non-mulched (1.67 g MJ-1) condition, while among planting dates, it was highest in first date of planting. The LAI, biomass production and yield of potatoes were found to be significantly correlated with iPAR and RUE. The predictive models were developed using the stepwise regression method to predict tuber yield from iPAR and RUE, which have R2 values of 0.96 and 0.99, respectively.