Pollen viability of Carica papaya L. 'Sunrise Solo' cultivar was estimated using in vitro germination and pollen stain tests. Two culture media described in the literature as efficient for pollen in vitro germination of C. papaya were used. Germination was higher in the media without essential elements but with a higher concentration of agar (65% compared with 51.5%). These results were compared with viability estimates based on staining pollen. The five stains used to test for pollen viability were: 2,3,5-triphenyl tetrazolium chloride - TTC, Alexander's stain, acetocarmine, iodine-potassium iodide and Sudan IV. Pollen viability estimated with TTC was 67.5% and similar to germination results providing a reliable estimate of in vitro germination. The four other stains overestimated pollen viability (> 90%), and their use should be restricted to determining cell constituents, and pollen grain integrity.
Carica papaya; in vitro germination; pollen staining; pollen viability
