Pollen Competition Improves Performance and Reproductive Output of the Common Zucchini Squash Under Field Conditions

Abstract

The objective of this study was to examine the effects of pollen competition on offspring quality in the common zucchini squash (Cucurbita pepo L.). In a controlled field study, we compared the performance of seeds that were produced under conditions of pollen competition (high pollen loads) to seeds produced under conditions of little or no pollen competition (low pollen loads). We found that seeds from high pollen loads were more likely to emerge and emerge more rapidly than seeds from low pollen loads. The high pollen load seedlings also tended to produce more flowers and fruits than the low pollen load seedlings. On a per-plant basis, the high pollen load progeny had significantly greater fruit volume, seed numbers, and total seed weight than the low pollen load progeny. We conclude that in zucchini, seeds produced under conditions of pollen competition are “superior” to seeds produced when pollen competition is minimal or absent. The significance of these results is considered in light of a previous study revealing nonrandom patterns of fruit abortion in this species.

Calcium and Boron Foliar Application in the Production and Quality of Zucchini Seeds

“…Whereas Lima and coauthors [18] observed lower production and quality (germination and vigor) of seeds in 'Caserta' zucchini when using less pollen grains in manual pollination. Davis and coauthors [25] observed that pumpkin seeds produced with a larger amount of pollen grains showed faster germination. Boron is very important to fruit and seed formation process, because it acts in cell walls formation, cell division, pollen grain germination, flowering and fruit formation.…”

“…There are reports that when there is a large amount of pollen grains on the stigma, they compete with each other and the most vigorous prevail in the fertilization of ovules, resulting in more vigorous seeds. Davis and coauthors [25] and Hormaza and Herrero [30] considered that the breeder when using large quantities of pollen grains establish competition capable of selecting the most vigorous ones. Thus, for the breeder, there is the possibility of selecting more vigorous populations only by exposing the female flowers to a large amount of pollen, without the need for large areas, only taking advantage of the intense competition among pollen grains [25].…”

“…Davis and coauthors [25] and Hormaza and Herrero [30] considered that the breeder when using large quantities of pollen grains establish competition capable of selecting the most vigorous ones. Thus, for the breeder, there is the possibility of selecting more vigorous populations only by exposing the female flowers to a large amount of pollen, without the need for large areas, only taking advantage of the intense competition among pollen grains [25]. So, the foliar application of Ca can result in greater amount of pollen grains per male flower used in a manual pollination.…”

Efecto de los visitantes nativos y exóticos sobre la germinación de Lepechinia floribunda (Lamiaceae)

“…Cuando el número de granos de polen depositado en un estigma supera el número de óvulos en el ovario puede existir competencia entre los micro gametofitos (teoría de competencia micro gametofítica; Mulcahy y Mulcahy. 1975, McKenna 1986, Davis et al 1987. Tubos polínicos de crecimiento rápido llegan antes a fertilizar los óvulos que tubos de crecimiento lento, y los tubos de crecimiento rápido generan progenie más vigorosa.…”

Improving genetic variation for seed vigor and yield components in squash (Cucurbita pepo l.) using honey bees as pollinators under shade net houses

“…Soon after germination, endogenous gibberellin (GA3 and GA4) concentrations increased in pollen tubes and were positively correlated with fruit growth (Zhang et al, 2010). Researchers Davis et al (1987), Schlichting et al (1990), and Quesada et al (1996) found that variations in pollen load (the number of pollen grains deposited on each stigma) had an impact on not only the number of seeds per fruit but also how quickly the progeny produced by a high pollenload germinated and developed.…”