Hospedabilidade de Meloidogyne javanica, Meloidogyne incognita e Pratylenchus brachyurus em genótipos de milho

Abstract

Hostability of Meloidogyne javanica, Meloidogyne incognita and Pratylenchus brachyurus in maize genotypes. Corn is one of the most significant commercial plants that originated in the Americas, with a history that spans millennia, this crop has significant importance both in human and animal food, increasing its demand every year due to the growing population increase and the diversity of uses, it has become a constituent part of the food culture of the Brazilian population (CONAB, 2018). Phytoparasitic nematodes form an important group of agricultural pathogens that infect plants and lead to reduced productivity (Ibrahim et al., 2016). According to studies carried out by Embrapa, in 2018 the damage caused by nematodes represented financial losses of approximately R$ 35 billion for the agricultural sector in Brazil. In this sense, the present study aimed to evaluate the hostability of nematode species Meloidogyne javanica, Meloidogyne incognita and Pratylenchus brachyurus in different maize genotypes. In the experiment conducted in a randomized experimental design under greenhouse conditions, 14 2 maize genotypes were tested for each nematode species, with 5 replicates in each genotype. Thus, a total of 70 vessels were obtained for each nematode species, resulting in a total of 210 vessels for the entire experiment. Nematode inoculation occurred 7 days after seedling thinning, with known initial populations. For Meloidogyne spp., the initial population was 5,000 eggs, while for Meloidogyne spp., the initial population was 5,000 eggs, while for Pratylenchus brachyurus, the initial population was 100 juveniles and/or adults. At the end of the experiment, the dry mass of the aerial part of each individual was determined and nematodes were extracted from the root and soil for reading and counting juveniles/eggs. The main parameter evaluated was the reproduction factor (RF); FR ≥ 1 means a good host, and FR <1 means a bad host. After data analysis, it was found that the genotype that presented poor hostability for the 3 nematode species studied was FS700 PWU, so that the same could be recommended for areas with management for the same 3 nematode species studied.