In order to assess the impact of different storage conditions on
temperature requirements, seeds stored for one year in room temperature,
freezer and oven were tested for germination in four
incubators adjusted at 15, 20, 25 and 30 _C under continuous illumination
with daylight fluorescent tubes. The germination was
conducted in 9-cm Petri-dishes containing one disk of Whatman
No. 1 filter paper, with 10 ml of distilled water. Four replicate
dishes, each with 20 seeds, were used for each treatment. Seeds
were considered to be germinated with the emergence of the radicles.
Germinated seedlings were counted and removed every
alternative day for 14 days following sowing.
The rate of germination was estimated using a modified
Timson’s index of germination velocity = RG/t, where G is the
percentage of seed germination at 2 d intervals and t is the total
germination period [20]. The maximum value possible using this
index with these experiments was 700/14 = 50. The higher the
value, the more rapid is the germination.
Two way-ANOVAs were used to assess the impact of storage
condition and seed storage period or temperature of incubation
on final germination percentage and germination speed. Tukey test
(Honestly significant differences, HSD) was used to estimate least
significant range between means. The germination percentages
were arcsine transformed to meet the assumptions of ANOVA.
The transformation improved normality of distribution of data.
All statistical methods were performed using SYSTAT, version 11.0.