An insight toward viability and in Vitro Germination of Salacca wallichiana and Salacca zalacca ‘Sumalee’ pollens and their ability to promote fruit set and fruit characteristics

The plants within the genus Salacca have the potential to sustain the rustic economic growth of Thailand. However, explicit knowledge related to pollen viability, germination capability, and appropriate techniques for fertility estimation for Salacca wallichiana and Salacca zalacca whose pollens are traditionally employed for cross-pollination are rarely available. Knowledge of fruit set and characteristics by those pollen donors is also limited. This research thus aimed to examine the viability of those species through 2,3,5-triphenyl tetrazolium chloride (TTC) testing and acetocarmine staining. The suitable culture medium for in vitro pollen germination was investigated. Fruit set and fruit characteristics at the early developmental stage of ‘Sumalee’ females were also elucidated. It was represented that 15% sucrose was optimized for checking pollen viability by TTC and germination tests. The highest pollen germination and tube growth were observed in Brewbaker and Kwack (BK) medium supplemented with polyethylene glycol and coconut water. By having a positively linear relationship with in vitro germination, both TTC and acetocarmine techniques were reliable to use for viability evaluation. Unexpectedly, size and shape could be used to distinguish between viable and non-viable pollens of both species. It was remarked from this research that the pollen of S. wallichiana seemed to have greater viability and germination capability than that of S. zalacca. Slightly higher fruit set was obtained by the former species as the latter significantly promoted higher fruit fresh weight and transverse diameter. This novel fills the knowledge gaps associated with the reproductive biology of Salacca plants, and contributes to improve fruit set and quality.