Seed Viability and Dormancy of 17 Weed Species After 21 Months in Alaska

Abstract

A 50-yr buried-seed study was initiated at Fairbanks, AK, in 1984. Seed of 17 weed species important in Alaskan agriculture were collected and buried 2 and 15 cm deep. Seed viability was determined initially and after recovery from the soil through a combination of germination tests and 2,3,5-triphenyltetrazolium chloride (TTC) treatments. Seed exhumed at 9 and 21 months were tested for viability and dormancy. Burial depth had a significant effect on seed longevity of corn spurry (Spergula arvensisL. # SPRAR), wild oats (Avena fatuaL. # AVEFA), pineappleweed [Matricaria matricarioides(Less.) C. L. Porter # MATMT], and bluejoint reedgrass [Calamagrostis canadensis(Michx.) Nutt.]. Viability was higher for seed buried at 15 than at 2 cm. Viability of shepherdspurse [Capsella bursapastoris(L.) Medik. #CAPBP] and pineappleweed seed did not decrease significantly over the 21-month burial period. In contrast, seed viability of wild buckwheat (Polygonum convolvulusL. # POLCO), common hempnettle (Galeopsis tetrahitL. # GAETE), wild oats, quackgrass [Agropyron repens(L.) Beauv. # AGRRE], and foxtail barley (Hordeum jubatumL. # HORJU) was less than 11% at the end of 21 months. There was no significant relationship between initial seed dormancy and viability after 21 months of burial.