Potencialidade de genótipos de aceroleiras (Malpighia emarginata D. C.) quanto ao enraizamento e resistência a nematóide visando a obtenção de porta-enxerto

Abstract

The Barbados cherry is a plant from the region of the Antilhas. The fruits present high content of ascorbic acid (Vitamin C) so that 100g of Barbados cherry juice can contain until 4,000mg of this vitamin. This fruit also contains pro-vitamin A, of the complex B and minerals as calcium, iron and phosphorus. The propagation of the Barbados cherry can be carried through through seeds, having as inconvenient the non uniformity of the orchard. Another way of getting seedlings would be through the grafting and cuttings. The method most important of propagation is the cuttings that confer uniformity in the plantation. The work had as objective to select of the Active Bank of Germoplasma of the UFRPE, through the cuttings, plants with good root growing and resistance to the infection by the root knot nematode Meloidogyne incognita race 2. The research was carried out, using 18 genotypes, during two periods, 58 and 111 days after the plantation of the cuttings in substratum to evaluate percentage of root development callus, alive plants and dead plants. The cuttings were transferred to polyethylene bags, with capacity of 2kg, in sterilized substratum to evaluate the infection, and the fresh relative biomass of the shoots and root system, gall index, egg mass index, eggs for root system and eggs for gram of root. It was taken out leaves of the plants at 20, 40 and 60 days after soil infestation with eggs of M. incognita. With this material it was carried out electrophoreses of isoenzymes where the bands expression, through the systems of α-esterase, fosfatase acid and peroxidase allowed to identify the relation of tolerance and resistance to M. incognita. There was significant difference among the 18 genotypes analyzed with regard to susceptibility to the nematode. The genotype 002-SPE presented the better percentage of root development, in the evaluated periods, which in the year of 2006 got the best result. The genotype 027-CMF was the most susceptive in contrast to the genotype 023-CMF superior to the other beeing less susceptible to M. incognita. The revelation of bands in the polyacrylamide gel allowed to identify regions of bands who related with the reaction of the genotype presence the pathogen. With this evaluation it was possible to generate a dendogram separating the 18 genotypes in two main groups. According to the matrix it was identified the degree of similarity among the genotypes. The high genetic variability of the genotypes increases success chances in improving barbados cherry for resistance to M. incognita.