Avaliação do potencial fixador de nitrogênio de genótipos de Desmanthus

Abstract

Found in different types of soils and climates, the legumes have a wide geographical distribution. They have a rich and important taxonomic diversity that places them as one of the largest families in numbers of species, and, for the most part, provide symbiosis with nitrogen-fixing bacteria, commonly known as rhizobia. Forage legumes also have direct effects on animal productivity due to their nutritional value, since participating in the animal diet contribute to increase the gain in weight as well as contribute more nutrients to the diet, besides being able to minimize productivity costs when compared with exclusive grass pastures, submitted to fertilization with mineral nitrogen. In this sense Desmanthus, a native genus of Brazil, presents as an interesting alternative as a source of forage legumes for the semi-arid tropics. Thus, this work aims to evaluate nitrogen fixation potential and symbiotic compatibility of rhizobial strains from the semi - arid region of Pernambuco with four accessions of Desmanthus that were differentiated through molecular marker ISSR. These were evaluated in polyethylene bags in a greenhouse in a randomized complete block design, with four replications, evaluating shoot dry matter (MSPA), root (MSSR), number of nodules (NN), nodule weight (MSN), accumulation (ANPA), and relative efficiency (ER), submitted to analysis of variance and the Scott Knott test at 5% probability. Each genotype of Desmanthus obtained greater fixation with certain isolates specifically, the genotypes 31D and 13AU were those that presented greater capacity of fixation of nitrogen, in relation to the other evaluated genotypes.