Panorama global da polinização de culturas de Fabaceae e influência da polinização na produção do feijão-comum (Phaseolus vulgaris L., Fabaceae)

Abstract

The Fabaceae family is one of the largest and most important botanical groups in the world, with species of great economic value, whether for human or animal consumption. Its species also play a valuable ecological role, as they support populations of pollinators (especially bees) in tropical and temperate environments. Pollination is considered one of the most important ecosystem services because it favors the agricultural production of more than 70% of cultivated species. However, in recent years pollinators have been in decline, resulting in a recorded reduction in agricultural production. There are few studies related to the reproductive requirements of cultivated Fabaceae species, and there are no studies that compile and statistically analyze the information already published on the subject. Among the cultivated Fabaceae, the common bean (Phaseolus vulgaris L., Fabaceae) stands out, which is important around the world and, especially, in Brazil, a country considered one of the world's largest producers and consumers of this legume. As with other species of the family, the reproductive requirements of common beans are poorly studied, with no consensus on the reproductive system (autogamy to allogamy) and the role and importance of pollinators for production being unclear. This thesis aims to: 1) Integrate pollination data through a meta-network in cultivated species of Fabaceae (hypotheses: there is a predominance of bees in pollination and there is a difference in studies conducted between tropical and temperate environments); 2) Analyze the influence of pollination on the production of common beans (Phaseolus vulgaris), using plantations in the Southern Agreste region of Pernambuco as a model. For the first objective, a systematic bibliographic survey was carried out in databases and personal collections. Information was collected on floral visitors, botanical species and climatic domain (temperate-tropical). To this end, 78 studies (covering six decades) with information on fifteen legume species and 208 floral visitors were accessed. The interaction matrix included 3,120 interactions. Eight modules were found, where most pollinators and all plants were included as peripheral. There was no difference in the proportion of studies conducted in tropical and temperate regions. The most representative floral visitors were bees, especially generalist species. However, economically important legumes were shown to be significant in maintaining a diverse fauna of pollinators. For the second objective, field data on reproductive system, pollen limitation and pollination were collected in two harvests. The following response variables were included in the analyses: number, morphometry and weight of fruits, number, morphometry, weight and germination of seeds. Reproductive efficiency and the pollen limitation index were calculated. Fruits, measurements, weight and germination from spontaneous self-pollination showed higher values in relation to manual cross-pollination. Reproductive efficiency was high, and there was pollen limitation only in one year. The bean flowers were visited by several groups of insects, with butterflies being the most frequent. Since none of them were considered effective pollinators, we could not test the hypothesis that production is favored by pollinators. The lack of pollinators can be explained by low temperatures and habitat changes. Beans can be considered a key crop in the current global pollinator crisis, since they do not depend on pollinators to produce food and support populations of several groups of insects.