Effect of storage on germination of R-55 repellent-treated seed of white spruce

Abstract

Determination of seed fate by radio-tracer methods have indicated seed losses to small mammals in Alberta could be as high as 50% during some years even when the widely accepted formulation of aluminum powder-endrin-arasan-latex had been applied to protect the seed supply in direct seeding operations. The need for a better seed coating formulation led to the development and evaluation of a potent rodent repellent, R-55, to protect spruce seeds from rodent damage. As part of the evaluation of this repellent, white spruce seeds were coated with a 4:1 (weight ratio) mixture R-55/graphite and latex. Treated and non-treated (controls) seed lots were stored in a refrigerator for a 2-year period during which eight germination tests were conducted at 2–3 month intervals to test seed viability. Except for one slight mid-winter decline in germination corresponding to a possible seasonal response of the seeds, no significant decline in germination resulted with storage up to 2 years duration. Studies with other coniferous seeds suggest considerable variability in seed species in response to the R-55/graphite coating and to storage of the treated seed.