Planting Method, Plastic Mulch, and Fumigation Influence Growth, Yield, and Root Structure of Watermelon

Abstract

<jats:p>A 2-year field study was conducted to determine the influence of planting method, i.e., transplanting or direct seeding, black plastic mulch, and soil fumigation on the vine growth, yield, and root structure of diploid hybrid watermelon. The experiment was a split-plot design with fumigation as the main plot and there were four replications. Methyl bromide (337 L·ha<jats:sup>−1</jats:sup>) was applied to the soil, which was then tarped. Black plastic mulch, 0.61 m wide × 2 mil (Visqueen 4020™) was applied to appropriate rows. Vine growth was measured during the season and yield was determined by the number and weight of fruit from each treatment. After fruit harvest, plant roots were excavated so that root structure was maintained with minimal damage and roots were photographed. Root systems were scored for tap root dominance and overall root distribution. Direct-seeded watermelon had more vine growth and higher yields in both years than transplanted watermelon. The advantage of direct seeding was likely the result of the growth and root expansion that occurred for these plants while the transplants were still in the greenhouse. Direct-seeded plants also displayed greater tap root dominance in each year than transplanted watermelon. Roots of both direct-seeded plants and transplants had a greater range in size distribution in both years under plastic mulch than those grown on bare ground. In late-planted watermelon, direct-seeded plants had more favorable vine growth and yield without the aberrant roots systems produced by transplants.</jats:p>

Advances in the Biology and Management of Monosporascus Vine Decline and Wilt of Melons and Other Cucurbits

“…Early studies on root development in transplanted and direct-seeded watermelon by Elmstrom (1973) showed that plants grown in small cells did not develop dominant taproots and produced plants with less-developed root systems compared to those that were direct seeded. Similar results were observed by Egel et al (2008) and Martyn (2007Martyn ( , 2008.…”

“…However, this likely is an artifact of the system, since the transplants were set out at the same time as direct seeding and were already five weeks old (Olson et al 1994). When watermelon transplants were started in the greenhouse at the same time as those direct seeded in the field and then transplanted to the field, direct-seeded plants produced the greatest yields and had better-developed root systems, including a dominant taproot (Egel et al 2008). Early studies on root development in transplanted and direct-seeded watermelon by Elmstrom (1973) showed that plants grown in small cells did not develop dominant taproots and produced plants with less-developed root systems compared to those that were direct seeded.…”

Mapping the genetic architecture of low‐temperature stress tolerance in citron watermelon

“…The optimum environmental temperature for effective watermelon plant growth varies from 18 to 35°C, where any temperature outside this range will slow down growth, maturation, and reduce crop yield (Korkmaz & Dufault, 2001). Transplanting of watermelon seedlings in temperate regions is often delayed to mid to late spring (April to mid‐May) when temperatures are warmer with minimal risks of plant death from low temperatures (Boyhan et al., 2000; Egel et al., 2008; NeSmith, 1999). In the United States, maximum consumption and premium prices for watermelon fruits occurs from June to mid‐July (Kaiser, 2012; https://www.ers.usda.gov/).…”