Parthenocarpic fruit set in triploid watermelon induced by CPPUand 2,4-D applications

Abstract

The localized application of the synthetic cytokinin CPPU ((2-chloro-4-pyridyl)-N-phenyl urea) to ovaries at flower opening was as effective as free pollination in setting parthenocarpic fruit in the triploid watermelon cultivar 'Reina de Corazones', and increased yield per unit land area by at least 50%, simply due to the lack of requirement for diploid pollen producing plants within the orchard. The application of the synthetic auxin 2,4-D (2,4-dichlorophenoxy acetic acid) as a full coverage spray, was also effective in setting fruit; total yield was however 10% smaller than in the CPPU-treated plots, but the cost of application was much less expensive. These applications had no adverse effect on fruit quality, and their effectiveness in commercial watermelon production was evaluated over 4 years. Localized applications of 2,4-D to ovaries were less effective in setting fruit, and increased hollow fruit.

Vermicomposta, auxinas sintéticas y producción de calabacita (Cucurbita pepo L.) en invernadero

“…La utilización de f itorreguladores de origen sintético, de composición análoga a las hormonas elaboradas por la propia planta inducidas por la polinización, es una alternativa empleada para promover el cuaje y producción de frutos partenocárpicos en invernadero sin empleo de insectos polinizadores (Ayala-Tafoya et al, 2012). Varios f itorreguladores comercializados con ese propósito, son formulados con base en auxinas: ácido indolacético, ácido 4-clorofenoxiacético, ácido naftalenacético y ácido 2,4-diclorofenoxiacético (Jankiewics y Acosta-Zamudio, 2003), y utilizados en melón (Li et al, 2002), sandía (Citrullus lanatus) (Maroto et al, 2005), pepino (Hikosaka and Sugiyama, 2015) y calabaza (Martínez et al, 2013;Queiroga et al, 2017).…”

Parthenocarpy in Cucurbitaceae: Advances for Economic and Environmental Sustainability

“…Hayata et al [27] first employed CPPU to treat unpollinated watermelon ovaries, resulting in seedless fruit formation. Moreover, a concentration of 200 g/m 3 CPPU did not impact the shape, soluble solids content, or rind thickness of the watermelon fruit, suggesting its direct applicability in production [22,27]. Watermelons treated with CPPU may exhibit a slight reduction in their sugar content compared to pollinated watermelons; however, this could be attributable to varietal differences [28,29].…”

“…The local application of auxin analogues to the watermelon ovary results in seedless watermelons with undesirable phenotypes, such as a smaller fruit size, thicker rind, and hollow cavities. However, when spraying over the entire plant, the resulting seedless watermelons show no significant difference from watermelons produced by pollination [22]. Qian et al [23] successfully induced parthenocarpy in cucumbers by applying the exogenous plant growth regulator naphthaleneacetic acid (NAA) 1 day before and on the day of flowering.…”

The effects of pumpkin rootstock on photosynthesis, fruit mass, and sucrose content of different ploidy watermelon (Citrullus lanatus)

“…Triploid cultivars are preferred by most consumers because of their sweeter taste and lack of hard seeds (Marr and Gast 1991). For this reason, the use of triploid cultivars has increased markedly, and they represent a significant proportion (50%) of the total watermelon production (Maroto et al 2005). Watermelon often suffers from soilborne pathogens.…”