Metodologia de avaliação a Pratylenchus brachyurus e reação de genótipos de soja aos nematoides das galhas e das lesões

• Autor(a) principal: Santos, Tânia de Fátima Silveira dos
• Data de Publicação: 2012
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFMT
• Texto Completo: http://ri.ufmt.br/handle/1/1114
• topic: Período de avaliação; Níveis de inoculo; Resistência; CNPQ::CIENCIAS AGRARIAS::ENGENHARIA AGRICOLA; Evaluation period; Inoculum levels; Resistance

Along with the expansion of soybean plantation, new problems came up as well, such as diseases caused by phytonematodes. Gall nematodes (Meloidogyne spp.) and (P. brachyurus) constitute two of the most important groups of nematodes for the crop. Due to the importance of these pathogens and the divergence in methodologies for the evaluation of tests to Pratylenchus spp., this paper aimed to evaluate methodologies of assembling and evaluation of tests to P. brachyurus as well as evaluate the reaction of soybean genotypes to P. brachyurus, M. javanica and M. incognita. The experiments were conducted in a greenhouse at Aprosmat, in the municipality of Rondonópolis, State of Mato Grosso, from March to November 2012. For the experiment testing methology, the experimental design was entirely at random, in factorial scheme 5x4, corresponding to five initial population levels of nematodes (0, 300, 600, 900 and 1,200 specimens of P. brachyurus) and four periods of evaluation (60, 75, 90 and 105 days after inoculation), with five repetitions. The soybean cultivars at use were: MG/BR 46 (Conquista), FMT Tabarana and TMG 115 RR. The inoculation followed different population levels. The evaluations occurred according to the period after the inoculations, amounting to the reproduction factor calculus. The second experiment was carried out in a factorial scheme 3x3, corresponding to cultivars (MG/BR 46 (Conquista), FMT Tabarana and TMG 115 RR) and containers (plastic vessels, ceramic vessels and small tubes) with six repetitions. The inoculum level used was of 600 specimens of nematodes per plant with evaluation at 90 days after inoculation. In the third experiment, the soybean genotypes tested were these ones: three lineages (UFUS 17, UFUS 02/Brown and UFUS 02) and twelve cultivars (UFUS Mineira, UFUS Uberlândia, UFUS Richness, UFUS Tikuna, UFUS Guarani, UFUS Carajás, UFUS Guará, UFUS Bahia, BRSMT Pintado (witness of11 susceptibility), MG/BR 46 (Conquista) (witness of resistance), FMT-Tabarana and TMG 115 RR) regarding the reaction to M. javanica, M. incognita and P. brachyurus. The design used was entirely randomized with 15 treatments and six repetitions. The inoculation process occurred about seven days after sowing with initial population of 600 specimens, to P. brachyurus with evaluation at 90 days and 5,000 eggs and juveniles to M. incognita and M. javanica with evaluation at 60 days. During both experiments the following variables were analyzed: SPAD reading, plant height, stem diameter, fresh and dry weight of the aerial part of the plants, root weight and reproduction factor. Every soybean genotype tested was susceptible, with FR varying from 8.33 to 23.18 to M. javanica and 6.16 to 23.0 to M. incognita. Genotypes UFUS 02 Brown and UFUS Tikuna showed FR lower than one to P. brachyurus. The ideal period for evaluation was between 75 to 89 days after inoculation, with 625 to 961 nematodes per plant. The containers used did not matter in the reproduction factor.