Avaliação de acessos de psidium spp. Visando resistência a o nematoide Meloidogyne enterolobii e à salinidade

Abstract

The world food production and the crop production has been affected by pests, insects, fungous, bacteria, viruses and nematodes and also by abiotic factors as water availability, soil salinity among others that affect several crops. The guava crop has important role in the economy, particularly in the family farming in Northeast Brazil especially in the irrigated crops of the Semiarid region. In this crop, Meloidogyne enterolobii, a gall nematode together with the Fusarium solani, cause a complex disease that make unviable several production areas. Besides these problems, the irrigated areas are prone to soil salinity that can also affect the crop. Thus, the search for genotypes in the genus Psidium to be used as resistant rootstock to these stresses or to be used in breeding programs that are devoted to obtain clones that allow the commercial production of guava in the country. Therefore, the aim of this work was to evaluate the reaction of Psidium spp. accessions to different doses of inoculum and also to evaluate the effect of osmoconditioning of Psidium guineense to saline stress. The first trial was carried out in a completely randomized bloc with eight replications. The accessions were inoculated with three inoculum densities (600, 1600 and 2000 eggs/mL) and they were evaluated 135 days after inoculation. The second trial was carried out in a completely randomized block with 25 seeds per replication, using osmoconditionated and not osmoconditionated seeds. It was found genetic variability among and within the accessions to reaction to M. enterolobii. Different inoculum densities can affect, in a differential way, the reproduction rate of the nematode in the root system of each plant and, thus, to make it difficult to identify the reaction of plants to the nematode M. enterolobii. Different electric conductivities affected the seeds regarding all variables evaluated in osmoconditionated and non condicionated seeds. The osmoconditioning can decrease the average and speed of seed germination of P. guineense in conditions of medium salinity level.