Plant Density‐Dependent Variation in Marketable Yield, Fruit Biomass, and Marketable Fraction in Watermelon

Abstract

An improved knowledge of effects of density of plants on yield of watermelon [Citrullus lanatus (Thunb.) Matsum & Nakai] would help efforts to determine optimal planting density and to anticipate the economic impact of factors that reduce density. We conducted a series of experiments to determine plant density‐dependent rates of change of marketable yield, fruit biomass, and marketable fraction in watermelon cultivar Sugar Baby. In single‐row plots, at least 3.7 m apart, density varied from 0.4 to 4.1 plants m2 (1000‐9000 plants ha−1). Marketable yield per unit area increased at linear rates of 0.5 to 1.1 Mg ha−1 per thousand plants ha−1 because fruit biomass increased at linear rates of 1.1 to 3.2 Mg ha−1 per thousand plants ha−1. The linear effect of plant density explained more than 90% of the increase in fruit biomass per unit area in most experiments. Density did not affect the fraction of fruit biomass that was of marketable quality. The linear rate of change in the marketable fraction did not exceed 3% per 1000 plants ha−1 on average in any experiment. Per plant, marketable yield and fruit biomass, respectively, decreased at curvilinear rates of 0.8 to 8.6 and 1.4 to 10.8 (kg plant−1 per thousand plants ha−1) (plants ha−1)2. These decreases were consistent with a constraint due to intraspecific competition. Our results support the hypothesis that efficiency of commercial production of watermelon could be increased by increasing planting densities.

Growth and Yield Response of Watermelon to in-row Plant Spacings and Mycorrhiza

“…Our results confirmed the findings of other studies, which suggest that fruit yield increases with an increase in plant density due to an increase in the plant number per area and the number of fruit per area (Brinen et al, 1979;NeSmith, 1993;Duthie et al, 1999;Sanders et al, 1999;Motsenbocker and Arancibia, 2002;Goreta et al, 2005). Frequently, the average fruit weight decreases with an increase in the plant density (Brinen et al, 1979;Sanders et al, 1999;Motsenbocker and Arancibia, 2002;Goreta et al, 2005); however, in our study, this relationship was only observed in 2003.…”

“…Other measures such as the implementation of plant density strategies, nutrient management and arbuscular mycorrhiza (AM) inoculation have been reported to have a positive impact on watermelon yield (Duthie et al, 1999;Kaya et al, 2003;Goreta et al, 2005).…”

“…High plant density is recommended in watermelon seed production because more fruit per area is achieved at a denser spacing (Edelstein and Nerson, 2002). When the number of plants per area is increased, the fruit number per area is enhanced, but the yield and fruit number per plant is reduced (Brinen et al, 1979;NeSmith, 1993;Duthie et al, 1999;Sanders et al, 1999;Motsenbocker and Arancibia, 2002). Thus, the relatively high yield at denser in-row spacings is due to a high fruit number per area (NeSmith, 1993;Duthie et al, 1999).…”

“…When the number of plants per area is increased, the fruit number per area is enhanced, but the yield and fruit number per plant is reduced (Brinen et al, 1979;NeSmith, 1993;Duthie et al, 1999;Sanders et al, 1999;Motsenbocker and Arancibia, 2002). Thus, the relatively high yield at denser in-row spacings is due to a high fruit number per area (NeSmith, 1993;Duthie et al, 1999). However, the fruit weight could be negatively impacted by high plant densities (Brinen et al, 1979;Sanders et al, 1999;Motsenbocker and Arancibia, 2002;Goreta et al, 2005).…”

Effect of Different Plant Densities on The Fruit Yield and Some Related Parameters and Storage Losses of Fodder Watermelon (Citrillus lanatus var. Cit

“…Duthie et al (1999) indicated that watermelon yield per plant tends to decrease with higher plant densities because interspesific competition intensifies and this directly suppresses plant growth, resulting in lower yields per plant. Although Duthie et al (1999) suggested that high plant populations (18150 and 12100 plants ha -1 ) provided the greatest marketable numbers of fruit, our results indicated that lower plant density (9524 plants ha) can be used to increase FWM number and weight. However, there is a paucity of information concerning the influence of plant population on FWM yield and yield components, particularly available information to growers.…”