Qualidade fisiológica, sanitária e reação de resistência a fitonematoides em sementes forrageira

Abstract

The experiments were performed in laboratory and greenhouse targeting following objectives: (i) evaluate the physiological quality and (ii) health black oats and ryegrass seeds produced in the 2014/2015 crop and millet seeds and sudan grass produced in the harvest of 2015/2016, from different production units located in Rio Grande do Sul.(iii) evaluate the reaction of species of grasses used in the Tillage System (SPD) with potential for use in cultivation with crop rotation aiming at the phytonematodes control genus Meloidogyne and Pratylenchus. The seeds were acquired eighteen producers of seeds located in the municipalities of Panambi, Ijuí, Pejuçara, Santa bárbara, Giruá, Cruz Alta, Júlio de Castilho, Santa Maria, Santo Ângelo, Passo Fundo, Marau e Vacaria. For the evaluation of the physiological quality (germination and vigor) and health (blotter test) the treatments consisted of 36 lots of black oat seeds, ten lots of ryegrass seeds, six lots of millet seed and six lots of seeds sudan grass. The evaluation of the resistance reaction or susceptibility of different species of foragers to phytonematodes was determined by inoculation of M. javanica, M.incognita, M. ethiopica M. and P. brachyurus in five cultivars of oat, two cultivars of ryegrass and cultivate millet and sudan grass. The results allowed to conclude that a) 58.34% of lots of black oats, 60% of lots of ryegrass, 66.67% of lots of pearl millet assessed were within the physiological quality established standards for commercialization, while that all lots of sudangrass culture presented germination below the minimum required. b) seeds had lower percentage of germination and vigor under ideal conditions showed time delay and emergency uniformity when subjected to adverse conditions. c) ryegrass seeds, millet and sudan grass not presented conveyed nematode, as in oat seeds was detected low incidence of nematode Aphelenchoides sp .d) various fungi were found in oat seeds, ryegrass, millet and sudan grass, made available by the marketing production units of Rio Grande do Sul. e) higher incidence of Phoma and Alternaria sp were observed in oat and ryegrass seeds. Whereas Fusarium sp. and Phoma sp were detected in millet seeds and sudan grass, respectively. f) to M. incognita, M. javanica and M. ethiopica cultivars of oat, ryegrass, millet and sudangrass were tough. g) The cultivars of ryegrass, millet and sudan grass were susceptible to P. brachyurus.