Evaluation of physical and physiological characteristics of seeds and seedlings of physic nut genotypes

The physic nut is an oleaginous plant that has distinguished itself as a drought tolerant native species, with a view to producing raw material for the biodiesel production. The purpose of the study reported here was to evaluate the quality of seeds and seedlings of five physic nut genotypes. The evaluated characteristics were: humidity content, mass of 1000 seeds, seed dimensions (using caliper gauge and sieves), germination tests, vigor tests (the first count of the germination test, electrical conductivity, accelerated ageing, seedling dry mass and length, emergence, emergence speed index and analysis of emerged seedlings). The experimental design was a completely randomized block with 4 replications. All data were submitted to analysis of variance by F test and the means were compared by the Tukey test at 5% probability. The physiological quality was not influenced by the seeds dimensions. The tests of accelerated ageing, emergence percentage, shoot dry mass, seedling length and dry mass were the bests at differentiating the genotypes. The Paraguacu genotype presented characteristics that were superior in relation to the others in the evaluations of accelerated ageing, root length and seedling total length.   Key words: Jatropha curcas, germination, vigor, viability, seed size.