Spruce Seed Viability: Dormancy of Seed From Four Species of Spruce

Abstract

The seedlings were of four species: White spruce [Picea glauca, (Moench) Voss.] ; Black Hills Spruce [P.g.albertiana, (S.Br.) Sarg.]; Colorado spruce [P. pzmgens, Engelm.] and Norway spruce [P. abies, (L) Karst.]. Seed, to produce these seedlings, was extracted from cones collected on the station. Exploration studies (3. 4) conducted with seed from individual seed trees of these species demonstrated the average number of seeds-per-cone to be 28, 23, 65 and 69, respectively. Tests conducted in the seed beds with this seed revealed an average of 14.6, 16.5, 54.1 and 50.9 per cent germination, respectively. This low germination may be the result of one or several factors involving seed viability. The effect of stratification upon germination of spruce seed appeared a logical starting point for seed viability studies.'Seed viability' may be defined as the percentage of seed capable of germinating when exposed to the most favorable conditions. 'Dormancy' has been defined as the physiological state of seed in which it is incapable for the most part of responding by growth to conditions favorable for germination.Barton (2) reported that seed of White and Norway spruce reacted most favorably to stratification at o0 C. for two months. Germination of 96 per cent and 90 per cent, respectively, was attained in 25 days while that of untreated controls was 48 per cent and 53 per cent. Seed of Colorado spruce was found to respond equally well t,o either O0 C. or 5' C. for one month. Germination of 79 per cent and 80 per cent was obtained in 16 days with the corresponding check germinating 47 per cent in 50 days.Results of studies conducted with spruce seed are reported (6) by the Forest Service of the United States. The essential points of this report are as follows. (1) White sruce seed exhibits a general dormancy which required 60 to 90 days of stratification at 41°F. to attain an average germination of 49 per cent. (2) Blue spruce proved variable, with some seed showing dormancy and others no dormancy. Stratification for 30 to 90 days was recommended, which resulted in an average germination of 73 per cent. (3) Norway spruce seed only occasionally has dormancy and requires no after-ripening treatment to attain an average of 70 per cent germination. (4) Seed of Black Hills spruce showed n.0 dormancy and required no stratification to give 44 per cent to 70 per cent germination. Crocker ( 5 ) placed Norway and White spruce in the same group with

Some effects of self-, cross-, and open-pollinations in Picea pungens

“…Thus the mean of 19.7 seeds/cone for selfing was only 23% of that for open-pollinations and only 40% of the cross-pollinations. Other comparable reports are not available for blue spruce, although Cram (1983) reported sets of 18 to 1 1 1 and a mean of 6 1 seeds/cone for open-pollinations of 2 1 trees.…”

“…He stated that yields above 100 seeds/cone were not uncommon, whereas 27% of the trees in this study had higher yields. The lower seed sets obtained by Hanover for open-pollinated provenances might be attributed to the harvesting of immature cones, because Cram (1956) found yields to increase with cone maturity.…”

“…When the cones of cach tree were fully mature, as indicated by floatation of 10 samples in turpentine (Cram 1956), all the cones from self-and cross-pollinations were harvested. In addition 100 cones from open-pollinations were harvested from cach tree.…”

“…Bongarten and Hanover (1982) mentioned a set of 14.9 seeds per cone from cross-pollinations and 0.2 from openpollinations of blue spruce. Hanover (1975) cited an average yield of 56 seeds per cone for 3 18 blue spruce in a provenance test, whereas Cram (1983) reported that seed set following open-pollinations of 21 trees averaged 61 seeds per cone.…”

“…Bongarten and Hanover (1982) mentioned a set of 14.9 seeds per cone from cross-pollinations and 0.2 from openpollinations of blue spruce. Hanover (1975) cited an average yield of 56 seeds per cone for 3 18 blue spruce in a provenance test, whereas Cram (1983) reported that seed set following open-pollinations of 21 trees averaged 61 seeds per cone.Selfing has been reported to reduce the set and germination of seed, also the growth and survival of seedlings, for several other conifer species (Bingham and SquilIace 1955;Gordon 1976;Mergen et al 1965; Sorenson and Miles 1982). This paper is a report on seed yields, seed and seedling characteristics of Picea pungens from a series of self-, cross-, and open-pollination studies.…”