Canadian Forest Service Publications

Genetic variation and control of chloroplast pigment concentrations and related needle-level traits in Picea rubens, Picea mariana, and their hybrids: moisture and light environmental effects. 2009. Barsi, D.C.; Major, J.E.; Mosseler, A.; Campbell, M. Trees 23: 555-571.

Year: 2009

Issued by: Atlantic Forestry Centre

Catalog ID: 30081

Language: English

Availability: Order paper copy (free)

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Chlorophyll pigment concentrations and proportions, nitrogen (N), and needle morphology traits are important com- ponents of growth and were examined in fi ve hybrid index categories from controlled crosses of various crosstypes, ranging from pure black spruce (BS) [Picea mariana (Mill.) B.S.P.] to pure red spruce (RS) (Picea rubens Sarg.) grown under controlled light and water environments. Black spruce had on average 10% greater total chlorophyll concentration (CHL) than RS. Red spruce had proportionately less chlorophyll a:b and CHL:CAR (carotenoid) ratios than BS. Nitrogen (N) concentrations were 1.75 and 1.60% for BS and RS, respectively. Black spruce had the low- est carbon (C):N ratio (29.7) and RS had among the highest (32.3). Interestingly, there was no difference in specifi c needle area among hybrid indices. Most of the chlorophyll pigment, C and N traits followed an additive inheritance model, evidenced by a near-linear relationship from BS to RS across hybrid indices. However, for CHL, CAR, and CHL:CAR ratio, parental analysis showed signifi cant male effects and non-signifi cant female and male x female interaction effects. Black spruce males had 15.1 and 9.6% higher CHL and CAR, respectively, than hybrid or RS males, thus showing an underlying paternally inherited genetic control. Controlling for N differences, analysis of co- variance (ANCOVA) showed that sun-grown seedlings had 22.2% or 300 mg g-1 lower CHL than shade-grown seed- lings. Controlling for N, ANCOVA showed that the drought-grown seedlings actually had 6.7% or 100 mg g-1 greater CHL than the irrigated seedlings. Sun plus drought conditions gave the lowest CHL, N, and CHL:CAR ratio of all treatments, showing an additive multi-stress effect. There was a signifi cant hybrid index x light effect as a result of rank changes. Sun-grown RS had the lowest CHL and N values, whereas shade-grown RS had among the highest CHL and N values. Red spruce are at a competitive disadvantage compared with BS and most hybrid spruce in high light, high drought, and high light plus drought conditions. Red spruce will be strongly limited in its distribution by successional opportunities resulting from prevalent harvesting practices such as clearcutting. Silvicultural modifi ca- tions and genetic restoration will be required to maintain RS on the landscape of northeastern North America.