Biologia floral, polinização e reprodução de Lagenaria Siceraria (Molina) Standl. Cucurbitaceae A. Juss.

Abstract

Lagenaria siceraria is a monoecious Cucurbitaceae of economic importance whose fruits have different uses in the food, craft, and domestic utility sectors. In Rio Grande do Sul state, the species is culturally known for the use of its dried fruits in the manufacture of the gourd, a bowl used to prepare “chimarrão”, a typical drink of the gaucho culture. Given its relevance and high reproductive dependence on pollinators, this work aimed to know the floral biology, pollinators, and the pollination requirements of L. siceraria. The study was carried out in the experimental area of the Instituto Federal Farroupilha, in the municipality of Frederico Westphalen-RS (27°23'31.6"S 53°25'58.7"W), and in a commercial farm, located in the municipality of Palmeira das Missões-RS (27°51'52.7"S 53°20'48.8"W). Anthesis started around 6:30 pm and lasted about 14 hours, covering night and daytime. The staminate flowers had dehiscent anthers before full flower opening, produced nectar during the whole flower life, and were produced 6.4 times more than pistillate flowers. The pistillate flowers did not have floral resources, they resemble to male flowers and maintained their receptive stigmas from beginning to end of anthesis. The species is self-compatible and it is not able to form fruit by agamospermy. In both study areas, the number of fruits produced was higher in manual cross-pollination, when compared to control pollination, indicating a pollination deficit. However, there was no significant difference between the mean values registered for the morphometric characteristics of the fruits in the different pollination treatments. Ten floral visitors, belonging to three orders, were registered in the flowers of L. siceraria: Hymenoptera (4), Lepidoptera-Heterocera (4), and Apodiformes (2) being bees and Lepidoptera the most frequent visitors and considered the species pollinators. Due to the low attractiveness, the frequency of visits to pistillate flowers was low, when compared to that registered in staminate flowers. Moreover, the results indicate the need for more than one pollinator visit to the flowers for fruit formation. This result indicates the need for pollinator management, aiming to increase the frequency of visits to pistillate flowers and increase L. siceraria fruit production. It is suggested management techniques use that include friendly practices to pollinators, to increase their availability in the cultivation areas.