Potencial germinativo de sementes de feijão caupi, cv. BRS Potengi, após condicionamento fisiológico

Abstract

Physiological conditioning consists of a technique that aims to stimulate the metabolism of seeds in the face of adverse situations, being applied to several cultures of economic expression, with the cowpea bean standing out for its relevance, mainly in the North and Northeast regions of Brazil. Thus, this study aimed to evaluate the effect of physiological conditioning and subsequent drying on the germination potential of cowpea seeds, cv. BRS Potengi. The first experiment consisted of comparing whether the use of the same seeds for all periods of imbibition (experiment I) or the use of new seeds at each period could interfere in the construction of the imbibition curve (30'; 1; 3; 6; 9; 12; 18 and 24 hours). Previously, the period of imbibition necessary for the seeds to reach phase II of the three-phase imbibition process, without starting phase III, was evaluated. In the second experiment, using imbibition methodology II, the seeds after each soaking period were divided into two fractions, one being kept moist (wet fraction) until sowing and the other submitted to the drying process (dry fraction). A completely randomized design was used, adopting for the second experiment a 2×7 factorial scheme + control (seeds without imbibition), that is, presence and absence of drying after physiological conditioning × periods of imbibition. It was evaluated: water content; germination (primary root protrusion); velocity index, velocity coefficient and mean primary root protrusion time and electrical conductivity. The imbibition curve can be efficiently conducted using the same seeds during all evaluation periods or using new seeds at each period. Aiming at using fewer seeds and better optimizing the time for preparing and conducting the soaking experiment, the methodology that uses the same seeds for all soaking periods is indicated. The physiological conditioning of seeds for 18 and 24 hours, without further drying, provides a faster emission of the primary root of the seeds of cowpea, cv. BRS Potengi. The seed drying process does not interfere with the beneficial effect of physiological conditioning.