Effects of plant population density and cultivar on growth, yield and yield components in groundnut (Arachis hypogaea 1.)

Abstract

An experiment was conducted at the University of Queensland Redland bay Farm (27°37′ S, 153°17′ E) in southeast Queensland, Australia to study response of groundnut cultivars [Improved Virginia Bunch, NC-7, Q18801 (Virginia types), TMV-2, McCubbin and Red Spanish (Spanish types)] to different plant population densities (6.3, 11.1, 25.0 and 100.0) arranged in square spacings. The objective was to study plant physiological and morphological characteristics associated with the optimum plant population density among groundnut cul- tivars. Leaf area index (LAI), interception of photosynthetically active radiation (PAR), total dry mass (TDM), dry mass (DM) partitioning, economic yield and yield components were measured. The results show that TDM and economic yield were both maximized at 25 plants m−2 in all cultivars and so were the radiation use efficiency (Ec), crop growth rate (CGR) and DM partitioning'toTeproductive components (pods and kernels). Overall, variation in economic yield (kernel DM) was determined by pod harvest index (HI), kernel HI, ratio of pod to peg plus pod number, kernel number per pod and kernel size. Most of these components were maximized at the optimum plant population density.