Plant Density‐Dependent Variation in Density, Frequency, and Size of Watermelon Fruits

Abstract

Quantitative analyses of the continuous response of components of the biomass of fruits of watermelon [Citrullus lanatus (Thunb.) Matsum & Nakai] to variation in plant density could provide insight into the mechanisms underlying effects of plant density on marketable yield. Per unit area, the linear response of fruit biomass to plant density recently has been shown to explain the linear response of marketable yield. In the current study we quantify plant density‐dependent variation in the size, density (no. per unit area), and frequency (no. per plant) of watermelon fruits. In single‐row plots, at least 3.7 m apart, plant density varied from 0.4 to 4.1 plants m2 (1000–9000 plants ha−1). In each experiment, the linear effect of plant density explained more than 80% of the variation in fruit density. Fruit density increased at linear rates of 0.6 to 1.1 thousand fruits ha−1 per thousand plants ha−1. The plant density‐dependent response of the size of fruits varied considerably among experiments but the frequency of fruits responded consistently. In four experiments, there was no evidence of an effect of plant density on fruit size but in three experiments, fruit size decreased at a curvilinear rate of approximately 2.0 (kg−1 fruit−1 per thousand plants−1 ha−1)(plants ha−1)2. Frequency of fruits decreased with plant density at curvilinear rates of 0.8 to 2.8 (fruits plan−1 per thousand plants ha−1)(plants−1 ha−1)2. The response of size of fruits and frequency of fruits, respectively, probably measured an environment‐dependent and an environment‐independent effect of intraspecific competition.

Use of Commercially Available Pollenizers for Optimizing Triploid Watermelon Production

“…The reason that no yield gain was realized with the interplanted 'SF800' versus the hill-planted 'SF800' treatment in 2006 like in 2005 is unclear. Reducing the inrow spacing decreases the size of the watermelon fruit (Duthie et al, 1999a(Duthie et al, , 1999bMotsenbocker and Arancibia, 2002;NeSmith, 1993). In our studies, triploid fruit size was unaffected by less spacing between plants (interplanting) compared with hill planting.…”

Desempenho de genótipos de melancia de frutos pequenos em diversas densidades de plantio

“…Resende & Costa (2003), trabalhando com Crimson Sweet obtiveram maior número de frutos por planta (1,4) nos maiores espaçamentos (3,0 x 0,8 m). Duthie et al (1999) também observaram maior número de frutos por planta em menores densidades de plantio. Estas observações não foram corroboradas com esta pesquisa.…”

Características produtivas da melancia em diferentes espaçamentos de plantio

“…O maior número de frutos por planta (1,35 frutos) foi apresentado pelo espaçamento 3,00 x 0,80 m. Resultados estes concordantes com Duthie et al (1999) que observaram maior número de frutos comerciais por planta em menores densidades. O menor número de frutos por planta, com o aumento da densidade de plantio, devese possivelmente à menor disponibilidade de espaço entre plantas, que promove maior competição por elementos nutritivos, água e luz e conseqüentemente diminuição da atividade fotossintética, produção de ramificações, folhas, flores e processo de polinização através das abelhas (principais responsáveis pela fecundação dos frutos).…”