Biologia floral da palma forrageira : ocorrência de mecanismos reprodutivos e causa do abortamento de frutos

Abstract

The hinterland and rural Pernambuco have a very difficult climatic conditions for agricultural operation, because they have concentrated rainy season in just three months of the year (Molion and Bernard 2000). Forage palm (Opuntia spp. And Nopalea cochenillifera Salm-Dyck) are part of a set of species that enable livestock in semi-arid regions, as they are productive and tolerant crops in low rainfall sites and high daytime temperatures, conditions similar to those recorded in much of the Brazilian semiarid region (Santos et al. 2001). In recent decades the growing area of ​​the cactus pear has been reducing due to cochineal carmine, Dactylopius opuntiae (Cockerell), insect causes damage to cladodes by injecting toxins. Cultivars traditionally used: Round, Giant and IPA-20 clone, the genus Opuntia species and Opuntia ficus-indica, have a high susceptibility to this pest (Vasconcelos et al 2009.). The Agronomic Institute of Pernambuco - IPA, through the breeding program of forage cactus, has sought for superior genotypes resistant to insect and more productive than the cultivars already released. For the generation of new cultivars are difficulties related to the reproduction of this plant, slowing the progress of breeding programs. Floral palm biology is quite complex, certain reproductive mechanisms such as apomixis and cleistogamia, are not fully understood, raising doubts as to the origin of sexual or asexual progeny. Another problem found in certain species of cactus pear fruit abortion is in controlled or non-intersections. The cause of these abscisões should be investigated and remedied, as the inability to produce fruits with viable seeds hampers sexual propagation, genetic variability source to be exploited by breeders. The objective of this study was to investigate the reproductive mechanisms of apomixis and cleistogamia in forage cactus Opuntia genus access; and identify possible high abortion causes fruit cultivar Miúda (Nopalea cochenillifera Salm-Dyck) and Clone F8 (Opuntia atropes Rose).