Influence of fungi associated with watermelon seeds on physiological and health quality

Abstract

Crop cultivation begins with direct sowing or seedlings production; it is important to use high quality seeds, highlighting physiological and health attributes. This study aimed to evaluate the physiological and health quality of watermelon seeds using different methodologies. We used four lots of untreated watermelon seeds of Crimson Sweet plant variety produced in the same year. Physiological performance was evaluated by a standard germination test, first count of germination, accelerated aging, electrical conductivity of seeds (Ec) and seedling emergence (S). Health quality was evaluated by a blotter method test where seeds were planted on well water-soaked blotters (filter papers), and incubated for seven days at 22oC under 12h alternating cycles of light and darkness; seedling symptom in paper roll test where seeds were planted such as a standard germination test, and incubated for seven days at 22oC under 12h alternating cycles of light and darkness; seedling symptom in autoclaved sand carried out with the seedlings’ emergence. First count of germination and electrical conductivity of seeds showed the lower quality of lots 1 and 2 in relation to the other lots, which were evaluated as similar in seedlings’ emergence. Identification of seedlings’ symptoms in paper roll and sand was not sensitive enough to quantify Aspergillus sp., Penicillium sp. and Rhizopus sp. presence in watermelon seeds. Electrical conductivity and first count of germination tests allow the evaluation of physiological performance of watermelon seeds properly, based on the correlation value (+/- 1). The blotter test is the most efficient test to evaluate health quality of watermelon seeds. Aspergillus sp. incidence is correlated with low physiological performance of watermelon seeds.