Nectar and pollen production in pumpkin (Cucurbita pepo L.)

Abstract

-(Nectar and pollen production in pumpkin (Cucurbita pepo L.)). Cucurbitaceae species depend on pollination by honey bees for fruit production. The overall objective of this work was to evaluate the potential of C. pepo for pollen and nectar production, that could help maintain colonies placed in the field. Plants of pumpkin were cultivated in field, in 1996 and 1997. Before anthesis, male flowers were covered to prevent visits by bees and other insects. After anthesis the flowers were uncovered and the following parameters were evaluated: 1) nectar production; 2) total sugar concentration in the nectar; 3) nectar replacement; and 4) production of pollen and flowers during the crop cycle. Nectar production varied from 18 to 79 µL flower -1 and increased progressively from 7h to 13h. The sugar concentration, measured at 7h, 9h and 11h, did not vary, averaging 50.5% ± 0.5% in 1996 and 40.5% ± 0.6% in 1997. At 13h the concentration decreased to 42% in 1996 and to 35% in 1997. Total daily nectar production was not influenced by removing nectar several times per day, indicating that nectar secretion is not stimulated or inhibited by frequent removal. The number of pollen grains did not differ in the two years, with an average of 43,669 ± 1,382 grains per flower. The peak rate of male and female flowers occurred from 60 to 66 days after planting (DAP) with 34.6 male flowers and 2.2 female flowers per plant, respectively. Cucurbita pepo has a potential for honey and pollen production of about 105 and 160 kg per hectare per season, respectively, which is enough to sustain, at least, five honeybee colonies.Key words -flower production, honey potential, nectar production, pollen production, sugar concentration RESUMO -(Produção de néctar e pólen em abóbora (Cucurbita pepo L.)). As espécies das cucurbitáceas dependem da polinização por abelhas para produzir frutos. O objetivo geral deste trabalho foi avaliar o potencial da C. Pepo para produzir pólen e néctar, no sentido de ajudar a manter colônias no campo visando a polinização. Plantas de abóbora foram cultivadas no campo, em 1996 e 1997. Antes da antese, flores masculinas foram cobertas para prevenir visitas de abelhas e outros insetos. Depois da antese as flores foram desprotegidas e os seguintes parâmetros foram avaliados: 1) produção de néctar; 2) concentração total de açúcar no néctar; 3) reposição de néctar e 4) produção de pólen e flores durante o ciclo da cultura. A produção de néctar variou de 18 a 79 µL flor -1 e aumentou progressivamente de 7h00 para 13h00. A concentração de açúcares, avaliada às 7h00, 9h00 e 11h00, não variou, apresentando uma média de 50,5% ± 0,5% em 1996 e 40,5% ± 0,6% em 1997. Às 13h00 a concentração decresceu para 42% em 1996 e para 35% em 1997. A produção diária de néctar não foi influenciada pela remoção do néctar em diferentes horas do dia, indicando que a produção de néctar não é estimulada ou inibida pela freqüente remoção. O número de grãos de pólen não variou nos dois anos, com uma média de 43.669 ± 1.382 grãos por flor. O...

Diel nectar secretion rhythm in squash (Cucurbita pepo) and its relation with pollinator activity

“…Our findings differ to some degree with those observed in two different varieties of C. pepo L. Rather than exhibiting a gradual but significant decrease through anthesis, nectar concentration remained constant in 'Greyzini' (Nepi et al 2001) and constant until just before flower closing in the pumpkin 'Howden' (Vidal et al 2006). Also, male flowers in 'Greyzini' produced most of their nectar before mid-anthesis, with no significant differences in volume between 0900 and 1200 h (Nepi et al 2001).…”

Bombus terrestris in a mass‐flowering pollinator‐dependent crop: A mutualistic relationship?

“…This study clearly demonstrates a mutualistic relationship between courgette flowers and B. terrestris that is beneficial to both, improving pollination success and colony dynamics (Bailes, Ollerton, Pattrick, & Glover, 2015;Holzschuh et al, 2016). Courgette, offers an abundant source of nectar to attract pollinators to its flowers for pollination (Vidal, Jong, Wien, & Morse, 2006). Indeed per m 2 , courgette offers more nectar (0.35 ml) than oilseed rape (0.30 ml), and field bean (0.092 ml) (Becher et al, 2016), and is therefore a high value mass-flowering crop in terms of nectar production.…”

Flower Sex Expression in Cucurbit Crops of Kerala: Implications for Pollination and Fruitset

“…Pollination efficiency in general and particularly in the monoecious plants is directly affected by the pollinator diversity (both species and abundance), functional diversity of pollinators, variation in the reward quality and quantity, diversity of floral type (staminate or pistillate), preference of key pollinators for foraging, and foraging time and visitation frequency of the pollinators with respect to pollen and stigma viability and receptivity 8,9,[15][16][17][18][19] . Floral traits also affect the pollination efficiency of flower visitors [20][21][22][23] .…”