STUDIES OF PRESERVATION OF LOTUS POLLENS AND INTERSPECIFIC LOTUS BREEDING

Lotus (Nelumbo nucifera) pollen viability was studied under various conditions, including 30°C room temperature, 8°C refrigerator, and -20°C freezer for storage periods of 7, 10, and 14 days, respectively. The pollens were stained with acetocarmine for pollen survival testing. Lotus pollens stored for 7 days at room temperature and 8°C refrigerator exhibited the highest viability percentages (88.00% and 89.00%, respectively). Subsequently, lotus anthers were irradiated with gamma rays at 0, 30, and 60 Gy and preserved at 8°C refrigerator for 7, 10, and 14 days. Examination of pollen viability showed that there was no statistically significant difference between the viability of pollens irradiated at 30 Gy and non-irradiated treatment after 7 days. However, over a storage period of 14 days, the survival percentage of 30-Gy irradiated pollen decreased more rapidly compared to the non-irradiated. Pollens from the mutant yellow lotus N. lutea were collected at Queen Sirikit Botanical Garden, Chiangmai, and stored under 8°C as the optimal condition for preserving lotus pollens and transferred to Thailand Institute of Nuclear Technology, Nakhon Nayok for interspecific crosses with white native lotus flowers (N. nucifera ‘Boontarik’). Only four plants survived and only one could flower. These cultivars successfully adapted to the Thai central plain climate and flowered after 4 months of planting. Plant characteristics were similar to Thai native ‘Boontarik’ lotus but its flowers showed creamy petals. This cultivar was unofficially named Nelumbo ‘Yellow Boontarik’.