Pollination requirements of seeded and seedless mini watermelon varieties cultivated under protected environment

Abstract

-The objective of this work was to evaluate the floral biology and pollination requirements of seeded and seedless mini watermelon varieties, and to determine the best varieties to cultivate under protected environment. Three seedless and two seeded (Minipol and Polimore) genotypes were tested. Flowers were monitored from the pre-anthesis stage to senescence, and fruit quality was also evaluated. The evaluated treatments were hand-geitonogamous pollination (MG), cross-pollination with pollen from the Polimore variety (MCP), cross-pollination with pollen from the Minipol variety (MCM), and restricted pollination. All varieties had monoecious plants with diclinous flowers, and the stigmas remained receptive throughout anthesis. Fruit set rates of 84.62% (MG), 61.54% (MCP), 48% (MCM), and 0% (restricted) were obtained for seeded varieties, but of 0% (MG), 76.36% (MCP), 82.69% (MCM), and 0% (restricted) for seedless varieties. Fruits did not differ in quality among treatments within each genotype. Therefore, all the studied varieties require a pollination agent and diploid pollen for fruit set to occur, regardless of the donor variety; and Minipol or Polimore with HA-5106 or HA-5158 are the varieties recommended for cultivation in protected environment.Index terms: Citrullus lanatus, flowering, fruit quality, fruit set, greenhouse. Requerimentos de polinização de variedades de minimelancia com e sem semente cultivadas em ambiente protegidoResumo -O objetivo deste trabalho foi avaliar a biologia floral e os requerimentos de polinização de variedades de minimelancia com e sem sementes, e determinar as melhores variedades para cultivo em ambiente protegido. Três genótipos sem semente (HA-5106, HA-5158 e HA-5161) e dois com semente (Minipol e Polimore) foram testados. As flores foram monitoradas da pré-antese à senescência, e a qualidade dos frutos também foi avaliada. Avaliaram-se tratamentos de polinização manual por geitonogamia (MG), de pólen cruzado da variedade Polimore (MCP), de pólen cruzado da variedade Minipol (MCM) e de polinização restrita. Todas as variedades apresentaram plantas monoicas e flores díclinas, e os estigmas permaneceram receptivos durante toda a antese. Foram obtidas taxas de vingamento de 84,62% (MG), 61,54% (MCP), 48% (MCM) e 0% (restrita) para as variedades com semente, mas de 0% (MG), 76,36% (MCP), 82,69% (MCM) e 0% (restrita) para aquelas sem semente. Os frutos não diferiram quanto à qualidade entre os tratamentos dentro de cada genótipo. Portanto, todas as variedades estudadas requerem um agente polinizador e pólen diploide para o vingamento de frutos, independentemente da variedade doadora; e Minipol ou Polimore com HA-5106 ou HA-5158 são as variedades recomendadas para cultivo em ambiente protegido.Termos para indexação: Citrullus lanatus, florescimento, qualidade dos frutos, vingamento de frutos, casa de vegetação.

Alfalfa ( Medicago sativa L.) seed yield in relation to phosphorus fertilization and honeybee pollination

“…Our results were consistent with the findings obtained by Taha and Bayoumi (2009) and Adamson (2011) , who reported that insect pollination plays a vital role in producing high yields due to their help in the pollination of crop plants. The importance of insects visits to flowers and their pollination activity has been recognized in squash ( Skinner and Lovett, 1992 ), watermelon ( Stanghellini et al, 1997 , Bomfim et al, 2015 , Giannini et al, 2015 , Kiill et al, 2016 ), radish ( Chandrashekar, 2005 ), cucumber ( Stanghellini et al, 1997 ), Egyptian riverhemp ( Sajjad et al, 2009 ), summer seed watermelon ( Taha and Bayoumi, 2009 ), sesame ( Kumar and Lenin, 2000 , Mahfouz et al, 2012 ), apple tree, avocado, and pear ( Giannini et al, 2015 ). Adding 300 kg P 2 O 5 /ha/year resulted in non-significant differences between open pollination and honeybee pollination for the number of pods/raceme, the number of seeds/pod, and the weight of 1000 seeds, while significant differences (p < 0.01) were observed for the successful fruiting index, abortion percentage, and seed yield/m 2 .…”

“…Improvements in artificial pollination increase the number of fruits in each branch. In cases where this plant cannot be pollinated, seed production is decreased substantially ( Bolanos et al, 2000 , Taha and Bayoumi, 2009 , Bomfim et al, 2015 ). In Saudi Arabia, seed production can be achieved using the honeybee ( A. mellifera L.) as managed pollinators ( Taha et al, 2016 ).…”

Morphological characteristics of pollen from triploid watermelon and its fate on stigmas in a hybrid crop production system

“…Seedless watermelon (triploid hybrids, 3n = 33) are produced by crossing a diploid and a tetraploid parent, and are now the dominant cultivar in major watermelon growing areas such as North America, where over 80% of watermelons are seedless 46 , 47 . Whilst diploid cultivars have viable, self-compatible pollen 29 and do not require cross-pollination 48 , triploid cultivars, with their three sets of chromosomes, do not produce viable pollen (male gametes) and need to be inter-planted with pollen-donating diploids 49 .…”

Pollen viability and incompatibility in indigenous rice bean (Vigna umbellata (Thunb.) Ohwi & Ohashi)

“…Emasculation was done during this interval because of the average temperature (20°C) required for anther dehiscence and increased chances for pollen viability (32). Pollination was performed on the next day from 5:00 to 7:00 AM because high receptibility will be observed in this time interval (33,34).…”