INVESTIGATIONS ON VIABILITY AND GERMINABILITY OF ENGLISH WALNUT POLLEN

The objective of this research was to determine the best methods for in vitro assays of pollen viability and germinability in English walnut (Juglans regia L.). Six cultivars were tested: ‘Serr’, ‘Vina’, ‘Pedro’, ‘Chase D9’, ‘Corne’, and ‘Franquette’. Pollen viability was determined by tetrazolium reaction and by a fluorochromatic test.
Moisture content of fresh collected pollen was also determined by drying the samples at 95°C for 30′. As regards the in vitro germinability, 4 different solid media with 2 quantities of sucrose (20–25%) and 2 levels of CaCl₂ (0.1–1 mM) were compared.
Percent of germination and the length of tube growth were evaluated after 24 h.
The same tests are now being performed on pollen stored in liquid nitrogen.

Fresh pollen with moisture content varying from 5.07 to 6.61% showed values of viability from 84% to 95% as measured by the tetrazolium reaction and from 75% to 90% for the fluorochromatic test.
Sucrose content did not consistently affect the rate of germination.
With regard to pollen tube length, the higher quantity of CaCl₂ promoted greater growth.

I International Symposium on Walnut Production

G. Vergano, L. Radicati, I. Martino

https://doi.org/10.17660/ActaHortic.1990.284.39