Análises de elementos químicos e populações endoparasíticas em cafeeiros inoculados com Meloidogyne exigua e Meloidogyne paranaensis

Abstract

It was analyzed 45 days after inoculation the endoparasitic population and the onset of symptoms induced by Meloidogyne exigua and M. paranaensis in resistant and susceptible coffee roots, through the quantification of five forms of development: wormlike, changed worm, ovoid and female with and without eggs in cvs. Mundo Novo, Apoatã and IPR 100, in addition to Genotype 1 - MG 179 pl1 R1 and Genotype 2 - MG 179 PL3 R1. Ten days after inoculation there was great fluctuation of wormlike (J2) of M. exigua and equality in this population of M. paranaensis in five genotypes. From 10 to 31 DAI, the fluctuation of changed worm and ovoid forms intensified both in M. exigua as M. paranaensis. From 31 to 45 DAI, the training of young females M. exigua was almost nil in Apoatã and IPR 100 and increased the population of females with eggs in the Mundo Novo and Genotype 1. The training of young females and eggs mass M. paranaensis was also low in all the trees except cv. Mundo Novo. It was observed longitudinal cracks in the new roots with M. paranaensis and rounded galls with apparent egg mass in the roots with M. exigua. These genotypes of coffee plants were evaluated for resistance to M. exigua 6 months after inoculation. Through X-ray microanalysis of the mineral elements of regions with and without galls on each coffee genotype were quantified. The vegetative development of genotypes with and without inoculation was evaluated on growth in height and diameter, and fresh weight of roots. The variables analyzed were subjected to multivariate canonical variables. The Apoatã and IPR 100 cultivars were resistant to M. exigua have to cultivate the Mundo Novo and the Genotypes 1 and 2 were susceptible. The calcium and iron were present in all samples being analyzed calcium detected in larger amounts in the genotypes associated with nematode, except Genotype 1. The potassium was detected only where the genotype was not associated with M. exigua. There was no significant interaction in the genotypes with the presence or absence of the nematode for vegetative variables, cvs. Mundo Novo and Apoatã, and Genotype 1 showed higher values for these variables. With multivariate canonical variate analysis found three dispersion patterns, the first between Mundo Novo and Genotype 1, the second between Genotype 2 and IPR 100 and a third standard composite cultivar Apoatã. Os Genotypes 1 and 2 showed resistance M . paranaensis and susceptibility to M. exigua. The calcium content in coffee root parasitized by M. exigua is higher compared to the level in healthy roots, can this element is related to the defense of the plant.