EARLY GROWTH AND SEEDLING MORPHOLOGY OF SPECIES OF Sesbania Scop. (Leguminosae, robinieae)

Abstract

The objective of this study was to characterize 17 accessions of Sesbania, representing S. exasperata, S. grandiflora, S. sesban, S. tetraptera and S. virgata at the seedling stage, and to evaluate the initial development during the first two months after planting. The trial was conducted in a greenhouse in a randomized block design, with 4 replications and 5 plants per plot. The traits recorded were: plant height (PH), from four observations at 15-day intervals, at 17, 32, 47 and 62 days after planting; length of hypocotyl (LH) and epicotyl (LEP); length (LE1) and width (WE1) of the first eophyll; and number of leaflet pairs of the second metaphyll (NLP), evaluated 17 days after planting. Univariate analyses of variance were performed, estimating the genetic parameters: coefficient of genotypic determination (b) and of genetic variation (CVg). Cluster analysis was also obtained, using the average Euclidean distance and Unweighted pair group method of arithmetic average (UPGMA) method. At 17 days after planting, S. exasperata presented the highest PH, followed by S. virgata. At 62 days after planting, S. sesban registered the highest PH. Length of hypocotyl displayed inter but not intraspecific variation. The characters LEP, LE1, WE1 and NLP showed both inter and intraspecific variation. Cluster analysis indicated the existence of 7 groups, separating the species and revealing intraspecific variation as well. The occurrence in low frequencies of two unifoliolate opposite eophylls for some species was observed, as well as bi- or trifoliolate first eophylls for one of the S. sesban accessions. These informations are basic for the selection of traits to be utilized for characterization and differentiation of Sesbania germplasm at the juvenile phase.