Morphological and Physiological Quality of Papaya Seeds in Relation to Seed Position within Fruit and Maturity Stages.

Papaya seeds quality is influenced by different factors, such as harvest time, the presence of sarcotesta, inhibitory compounds in theseeds, seed position in the fruit, among others. The objective of this study was to evaluate morphological and physiological quality of the papaya seeds at different maturation stages and locations within the fruit. Papaya fruits of Tainung 01 hybrid fruits were harvested at stage 1 of maturation. The fruits were stored in a laboratory environment until they reach maturity stages 3, 5 and final. The seeds were extracted from the extremities and the central portion of the fruits at maturation stages 1, 3, 5 and final. Germination (assessed at 15 and 30 days), percentage of dormant seeds, germination speed index, accelerated aging, seedling emergence, X-ray test and seedling length using the program Seed Vigor Imaging System® were determined. The experiment was conducted in completely randomized design in factorial (two locations of the fruit and four maturation stages) with four replications. The means were compared by Tukey’s test at 5% probability. It was found that the post-harvest maturity of fruits improves the physiological quality of papaya seeds, promoting a reduction in the number of dormant seeds and empty seeds. High physiological quality seeds can be obtained from central position of fruits at maturity stages 5 and final, corresponding to 75% and 100% maturation. The X-ray test showed to be adequate to evaluate the papaya seed quality, allowing to distinguish empty seeds and seeds with normal embryo in a sample.