Physiological components of seed quality in runner-type peanut during seed formation

Seed is one of the most expensive costs in peanut (Arachis hypogaea L.) production, and the use of high-quality seed is important to provide the greatest yield potential. Physiological seed quality, represented by a combination of germination, vigor, desiccation tolerance, and longevity, is progressively acquired during seed formation. When all components reach their maximum, seeds achieve the highest physiological quality. The objectives of this study were to identify the acquisition pattern of the physiological components of seed quality, to determine the timing in which the maximum physiological quality is achieved during seed formation, and to define the timing in which seeds acquire and further break primary dormancy in peanut. A 3-year field study was conducted using the cultivar Georgia-06G. Plants were inverted when growing degree days reached 2500 for all fields, and a maturity board profile was used to classify the pods into the maturity classes. Seeds were split into two groups, treated and non-treated, with ethephon to break potential primary dormancy. Water content, germination, vigor, desiccation tolerance, and longevity were tested in the seeds. Seed mass maturity was reached in the “orange” class. Maximum germination and vigor were achieved between “brown 1” and “brown 2”. Primary dormancy was acquired between “orange” and “brown 1” and broken after artificial drying. Maximum desiccation tolerance was observed in “brown 1”, whereas maximum longevity was achieved only in “black 2”. Considering all physiological quality components, peanut seeds achieved the maximum physiological quality between “brown 1” and “brown 2”.