Diversidade de Desmanthus spp. e Stylosanthes spp. do semiárido pernambucano

Abstract

The Desmanthus and Stylosanthes genus are legumes of the semi-arid, It has great potential for Forage Crops for its nutritional value, hardiness and symbiosis for nitrogen fixation. These genera spontaneously in the sown region of Pernambuco. Thus, knowing the variability of these forage plants is essential for such information to be used as a basis for future research, contributing to the utilization of genetic resources available in genetic improvement. This study had as objective measure the genetic and morphological diversity in Desmanthus and Stylosanthes genus with naturally occurring in Pernambuco. For Stylosanthes, collections were made in the semi-arid region of Pernambuco in September 2015. The species plants were identified in the herbarium of the Instituto Agronômico de Pernambuco-IPA. The accesses were propagated via seeds and cultivated between November 2015 and April 2016 in the Department of Animal Science of the Federal Rural University of Pernambuco at the Dois Irmãos Campus in Recife, Pernambuco. To identify the diversity of Stylosanthes scabra populations, 76 plants were collected from four populations located in the municipalities of Santa Cruz do Capibaribe, Caetés, Sertânia and Petrolina. With the genus Desmanthus, the morphological characterization was performed in 18 accesses and molecular characterization by ISSR marker in 26 accessions. All accesses of Desmanthus belonging to the germplasm bank of forage legumes of the Federal Rural University of Permambuco- UFRPE in the Academic Unit of Serra Talhada-PE implemented in 2012. There is variability in the two genus, however, the Stylosanthes presents greater variability. It was verified the presence of quite contrasting species. S. scabra and S. seabrana were distinguished by higher production of dry leaf mass. In the genus Desmanthus, accesses 235C and 22SA deserve special attention because they are isolated within their groups in both morphological and molecular analyzes and are indicated to be used in breeding programs of the species. Considering the populations of S. scabra. The species presents greater variability among populations (60%) than within populations (40%). The high morphological and genetic variability of the accesses evidences the importance of the collection for future works of genetic improvement.