Physiological maturation of cowpea seeds

Abstract

-The seed maturation process is genetically controlled and involves an arranged sequence of morphological and physiological changes extending from fertilization to its total independence from the mother-plant. These changes also include a set of preparatory phases for the germination process, which are characterized for the synthesis and accumulation of nutrient reserves. Thereby, this study was developed aiming at assessing development and physiological quality of cowpea seeds during maturation process. To this, the cowpea pods of cultivar BRS-Guariba were harvested from the tenth day after anthesis (DAA) until the twenty sixth DAA, with four days intervals. Immediately after each harvest, seeds were manually extracted from the pods and then subjected to the following determinations: moisture content, first count of germination, final germination percentage, length of shoots and roots, hypocotyl diameter, and seedling dry mass. The experiment was conducted in a completely randomized design, with five treatments (DAA), and four replications to each treatment. Results have shown that cowpea seeds have fairly fast physiological maturation, and that seeds harvested between 14 and 18 DAA have better vigor as well as higher germination rates; thus the harvest performed during this period does not cause damages to seeds.Index terms: Vigna unguiculata L., physiological quality, vigor. Maturação fisiológica de sementes de feijão-caupiRESUMO -A maturação da semente é controlada geneticamente, envolvendo uma sequência ordenada de alterações verificadas a partir da fecundação até que se tornem independentes da planta-mãe. Essas alterações compreendem um conjunto de etapas que preparam para o sucesso da futura germinação, caracterizada pela síntese e acúmulo de reservas. Dessa forma, este estudo teve por objetivo avaliar o desenvolvimento e qualidade fisiológica de sementes de feijão-caupi durante o processo de maturação. Para isso, vagens da cultivar BRS-Guariba de feijão-caupi foram colhidas a partir do décimo dia após a antese (DAA) até o vigésimo sexto DAA, com intervalos de quatro dias. Após cada coleta, as sementes foram manualmente extraídas das vagens e submetidas às seguintes determinações: grau de umidade, primeira contagem de germinação, porcentagem final de germinação, comprimento de parte aérea e raízes, diâmetro do hipocótilo e massa seca das plântulas. O experimento foi conduzido em delineamento experimental inteiramente casualizado, com cinco tratamentos (DAA) e quatro repetições cada. As sementes de feijão-caupi apresentam maturação fisiológica bastante rápida e aquelas colhidas entre 14 e 18 DAA têm melhor vigor e maior porcentagem de germinação; assim, colheita deve ser realizada durante esse período, pois não causa danos às sementes.Termos para indexação: Vigna unguiculata L., qualidade fisiológica, vigor.

Pre-Harvest Desiccation in Productivity and Physiological Quality of Cowpea Seeds

“…To produce seeds, the harvest should be carried out at or near the physiological maturity, as the delay may negatively influence the quality of the seeds due to their exposure to possible unfavorable environmental conditions (Terasawa et al, 2009). However, Nogueira et al (2014), evaluating the development and physiological quality of cowpea seeds, verified that in the physiological maturity the water content of the seeds was 53.6%; according to Terasawa et al (2009), seeds with high water content make mechanized harvesting impossible, as there are difficulties for picking and trail, as well as the occurrence of severe levels of mechanical damage by kneading. As a result, farmers await the reduction of the seed water content and the natural defoliation of the plant and begin harvesting as soon as possible.…”

Germinação E Vigor De Sementes Crioulas De Feijão-Caupi

“…Dessa forma, a semente se torna o principal insumo nos sistemas de produção, e a sua qualidade fisiológica é o principal fator responsável pelo bom desenvolvimento inicial em campo, gerando boa safra e alta produtividade (NOGUEIRA et al, 2014). O potencial fisiológico da semente está relacionado com os atributos de germinação e o vigor.…”

Physiological Maturity and Determination of the Harvest Time of Vigna unguiculata L. Walp.

“…The difficulty of obtaining seeds of good physiological quality is among the limiting factors in the production of cowpea, since the seeds are one of the main inputs of the agricultural production, where the quality is an important factor to obtain stands of uniform and vigorous plants, directly reflecting the yield [2].…”