Physiological response of groundnut (Arachis hypogaea L.) to thinning time and intensity after anthesis

Two experiments were carried out to study groundnut (Arachis hypogaea L.) response to thinning time and intensity after anthesis at Redland Bay Farm, Southeast Queensland, Australia, during 1987/88 (Experiment 1) and 1989/90 (Experiment 2). Six cultivars were included in Experiment 1: Improved Virginia Bunch (IVB), NC7, Q18801 (Virginia type), TMV-2, McCubbin and Red Spanish (Spanish type); and two cultivars in Experiment 2: IVB and Red Spanish. These were thinned to 0 (control) or 50% at 42 or 91 days after planting (DAP) in Experiment 1; and 0 (control), 33, 50, 66 or 75% at 42 DAP in Experiment 2. Treatments were laid out in a randomized complete block design (RCBD) with three replications in both seasons. A 50% thinning at 42 DAP reduced intercepted photosynthetically active radiation but fadiation use efficiency, crop growth rate and total dry mass increased in all cultivars by maturity. A 50% thinning at 91 DAP significantly reduced groundnut production. Also, a thinning intensity of >66% reduced gr...