Technique for in vitro pollen germination and short-term pollen storage in caladium

Abstract

The sporadic nature of inflorescence production and flower protogyny in caladium (Caladium xhortulanum Birdsey) makes it desirable to store pollen and to rapidly assess its viability for cross-pollinations in breeding programs. This study was conducted to develop a procedure to determine caladium pollen viability and to use that procedure to evaluate the effect of short-term storage conditions on pollen viability. The sucrose level in the culture medium was found to have a significant impact on the in vitro germination of caladium pollen; a concentration of 6.8% was determined to be optimal for pollen germination. Caladium pollen lost viability within 1 day under room (24°C) or freezing (-20°C) temperatures, but could be stored at 4°C for 2 to 4 days. Pollen stored at 4°C produced successful pollinations. Data obtained from large-scale greenhouse pollinations supported use of this in vitro germination assay as a convenient way to evaluate caladium pollen viability (and fertility).