Carbon assimilation variation and control in Picea rubens, Picea mariana, and their hybrids under ambient and elevated CO2

Genetic maps provide an important genomic resource of basic and applied significance. Spruce ( Picea ) has a very large genome size (between 0.85 × 1010 and 2.4 × 1010 bp; 8.5–24.0 pg/1C, a mean of 17.7 pg/1C ). We have constructed a near-saturated genetic linkage map for an interspecific backcross (BC1) hybrid of black spruce (BS; Picea mariana (Mill.) B.S.P.) and red spruce (RS; Picea rubens Sarg.), using selectively amplified microsatellite polymorphic loci (SAMPL) markers. A total of 2284 SAMPL markers were resolved using 31 SAMPL–MseI selective nucleotide primer combinations. Of these, 1216 SAMPL markers showing Mendelian segregation were mapped, whereas 1068 (46.8%) SAMPL fragments showed segregation distortion at α = 0.05. Maternal, paternal, and consensus maps consistently coalesced into 12 linkage groups, corresponding to the haploid chromosome number (1n = 1x = 12) of 12 in the genus Picea. The maternal BS map consisted of 814 markers distributed over 12 linkage groups, covering 1670 cM, with a mean map distance of 2.1 cM between adjacent markers. The paternal BS × RS map consisted of 773 markers distributed over 12 linkage groups, covering 1563 cM, with a mean map distance of 2.0 cM between adjacent markers. The consensus interspecific hybrid BC1 map consisted of 1216 markers distributed over 12 linkage groups, covering 1865 cM (98% genome coverage), with a mean map distance of 1.5 cM between adjacent markers. The genetic map reported here provides an important genomic resource in Picea, Pinaceae, and conifers.

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Growth and allocation of Picea rubens, Picea mariana, and their hybrids under ambient and elevated CO2

Canadian Journal of Forest Research ◽

10.1139/cjfr-2014-0525 ◽

2015 ◽

Vol 45 (7) ◽

pp. 877-887 ◽

Cited By ~ 6

Author(s):

John E. Major ◽

Alex Mosseler ◽

Kurt H. Johnsen ◽

Moira Campbell ◽

John Malcolm

Keyword(s):

Picea Mariana ◽

Black Spruce ◽

Negative Relationship ◽

Growth Efficiency ◽

Picea Rubens ◽

Tree Size ◽

Total Biomass ◽

Hybrid Index ◽

Shoot To Root Ratio ◽

Size Interaction

Red spruce (RS; Picea rubens Sarg.) – black spruce (BS; Picea mariana (Mill.) B.S.P.) controlled crosses (100%, 75%, 50%, 25%, and 0% RS, balance BS) showed increasingly greater height with increasing proportion of BS in each successive year. Height growth of 4-year-old ambient CO2 (aCO2) grown trees was highly correlated with height of 22-year-old field-grown trees of the same or similar crosses. Bud flush was earliest in BS and declined linearly with increasing proportion of RS with no significant CO2 effect. Percent stem (stem + branches) mass increased under elevated CO2 (eCO2), a quarter of which was due to ontogeny. Conversely, percent needle mass had a significant negative relationship with increasing tree size, and there was a CO2 × tree size interaction. Shoot-to-root ratio was greatest for BS, whereas RS had among the lowest. Hybrid index (HI) 50 had the greatest root mass allocation, lowest shoot-to-root ratio, and among the greatest total mass under eCO2. Growth efficiency increased with tree size and eCO2 but decreased with HI. Percent total biomass stimulation under eCO2 was lowest for BS at 6.5%, greatest for HI 50 at 20.3%, and RS had 17.5%.

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