Qualidade de sementes e divergência genética em (Cajanus cajan L. Millspaugh)

Abstract

Creole seeds are sources of genetic variability, however, their use is of great importance for family farming. Therefore, producing and purchasing good quality seed is essential for the proper development of a crop. The species Cajanus cajan (L.) Millspaugh (Fabaceae), known as pigeon pea, was introduced in Brazil because its development on soils with low fertility, and its tolerant to drought. Thus, the objective of this study was to evaluate the physiological potential and the genetic divergence in creole seeds of different varieties of pigeon pea. The experiments were carried out at the Laboratory of Seed Analysis and Phytopathology, at the Center of Agricultural Sciences, from the Federal University of Paraíba, in Areia - PB. It was analyzed for the different varieties regarding their physical quality (seed water content, weight of thousand seeds and physical purity), physiological quality (germination, emergency and vigor tests), sanitary quality (examining the infested seeds and identification of pathogens presence), addition to genetic diversity characteristics (germination, vigor, width, thickness, seed length and weight of one thousand seeds) of different varieties of pigeon pea. The highest levels of water content were found in lots 3 and 4 of the Precoce variety of pigeon pea, although they had the lowest percentage of physical purity together with lot 1 of the Rajada variety. The Manteiga variety and lot 3 of the Precoce variety obtained the highest weight of seeds. The highest percentages of germination for creole seeds of pigeon pea were obtained in the lots of the varieties Precoce and Manteiga, while the lowest percentages of germination were observed in lots 1 and 2 seeds of the variety Rajada. Lots 1 of the Precoce variety and the lot of the Manteiga variety were the most vigorous, however lots 1 and 2 of the Rajada variety were the least vigorous. The creole seeds of pigeon pea had a diverse microbiota, being Aspergillus sp., the fungus genus of greater occurrence, however, only the seeds of lot one of the variety Rajada had its physiological quality compromised. In the native varieties of pigeon pea there is genetic variability for all characteristics evaluated, except for the width of the seeds. The characteristics that most contributed to explain the variation among the creole varieties of pigeon pea were the weight of a thousand seeds, first germination count, percentage of germination and seed thickness.