Negative heterosis not apparent in 22-year-old hybrids of Picea mariana and Picea rubens

1998 ◽  
Vol 76 (3) ◽  
pp. 434-439 ◽  
Author(s):  
Kurt H Johnsen ◽  
John E Major ◽  
Judy Loo ◽  
Donald McPhee
Keyword(s):  
Gas Exchange ◽  
Picea Mariana ◽  
Black Spruce ◽  
Picea Rubens ◽  
Red Spruce ◽  
Hybrid Index ◽  
Individual Tree ◽  
Class 1 ◽  
Hybrid Class ◽  
Old Trees

Work from the 1970s indicated that, relative to either parent species, crosses between red spruce (Picea rubens Sarg.) and black spruce (Picea mariana (Mill.) B.S.P.) were inferior with respect to both growth and photosynthesis. We re-examined the hypothesis that there is negative heterosis in hybrids of red and black spruce using 22-year-old trees in a common garden study planted on two sites. The trees were the product of controlled crossings and represent a continuum from hybrid class 0 (pure black spruce) to hybrid class 1 (pure red spruce). Progeny of all controlled crosses were measured for height and diameter. A subset of families were measured for gas exchange and were assessed using a hybrid index based on needle color, needle configuration, twig ridges, twig bark color, vegetative bud color, and cone scale morphology. Tree growth rate linearly declined with the increasing proportion of red spruce germplasm (increasing hybrid index). In 1994, intermediate hybrid index classes did not differ in gas exchange from either pure black spruce (hybrid index class 0) or pure red spruce (hybrid index class 1), and in 1996, hybrids displayed slightly higher rates of gas exchange. Thus, negative heterosis was not apparent in 22-year-old trees. Individual tree hybrid index generally agreed with expectation based on midparent means, although the relationship was stronger on the higher productivity site (r2 = 0.91) than the poorer productivity site (r2 = 0.54).Key words: black spruce, heterosis, hybrid, photosynthesis, red spruce.

A high-density genetic linkage map of a black spruce (Picea mariana) × red spruce (Picea rubens) interspecific hybrid

Genome ◽  
2011 ◽  
Vol 54 (2) ◽  
pp. 128-143 ◽  
Author(s):  
Bum-Yong Kang ◽  
John E. Major ◽  
Om P. Rajora
Keyword(s):  
Picea Mariana ◽  
Interspecific Hybrid ◽  
Genetic Linkage ◽  
Genetic Linkage Map ◽  
Black Spruce ◽  
Picea Rubens ◽  
Red Spruce ◽  
Linkage Groups ◽  
Genomic Resource ◽  
Map Distance

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.

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

2015 ◽  
Vol 45 (7) ◽  
pp. 877-887 ◽  
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%.

Reproductive barriers and hybridity in two spruces, Picea rubens and Picea mariana, sympatric in eastern North America

2005 ◽  
Vol 83 (2) ◽  
pp. 163-175 ◽  
Author(s):  
John E Major ◽  
Alex Mosseler ◽  
Kurt H Johnsen ◽  
Om P Rajora ◽  
Debby C Barsi ◽  
...  
Keyword(s):  
Picea Mariana ◽  
Black Spruce ◽  
Common Garden ◽  
Picea Rubens ◽  
Reproductive Phenology ◽  
Interspecific Crosses ◽  
Hybrid Index ◽  
Morphometric Traits ◽  
Seedling Traits ◽  
Species Specific

Hybridization between red spruce (Picea rubens Sarg.) and black spruce (Picea mariana (Mill.) BSP), late- and early-successional species, respectively, has resulted in identification and management problems. We investigated the nature and magnitude of reproductive and life-cycle success barriers in controlled intra- and inter-specific crosses of red and black spruce. We quantified a number of reproductive, germination, phenological, and performance traits, and examined traits by parental pedigree and hybrid index. Species' pollen had no effect on number of aborted or nonpollinated ovules. Controlled intraspecific crosses had, on average, 6.6 times more filled seeds than interspecific crosses. Cone and seed morphometric traits were species specific, with seed traits showing negative hybridization effects on both species. Germination, cotyledon number, and seedling height had significant species-specific traits, with hybrids showing an additive or slightly negative heterosis. Severe, negative heterosis appears to be of limited importance as an isolating barrier between red and black spruce. Reproductive phenology was remarkably similar among species and hybrid progenies when grown in common garden experiments. Crossability barriers are clearly paramount in maintaining the separation of the species. Ecological separation based on ecophysiological differences (e.g., shade tolerance) also represents an important prezygotic barrier for minimizing the negative effects of hybridization (e.g., postzygotic inviability) on reproductive fitness.Key words: cone, seed and seedling traits, genetic variation, phenology, red and black spruce.

Genetic variation of red spruce in the Maritimes

1988 ◽  
Vol 18 (6) ◽  
pp. 703-709 ◽  
Author(s):  
D. P. Fowler ◽  
Y. S. Park ◽  
A. G. Gordon
Keyword(s):  
Genetic Variation ◽  
Black Spruce ◽  
Tree Improvement ◽  
Red Spruce ◽  
Hybrid Origin ◽  
Diameter Growth ◽  
Hybrid Index ◽  
Strongly Correlated ◽  
Variation Pattern ◽  
Breeding Zone

Red spruce, Picearubens Sarg., from 30 provenances was tested over a 23-year period at six locations in the Maritimes Region of Canada. Twenty-eight of the provenances were from the Maritimes Region and two were from West Virginia. Hybrid index was used to distinguish pure red spruce from red–black spruce derivatives. Trees from three of the Maritimes provenances were considered to be of hybrid origin. These three provenances produced the fastest-growing trees in the tests. The genetic variation pattern, at the provenance level, in pure red spruce of Maritimes origin is not well defined. Use of seed from provenances identified as superior for reforestation would result in about 10% greater height and diameter growth than would be obtained from average seed. The use of seed of poor provenances could result in a corresponding loss of growth. Height at ages 10, 15, and 23 years and diameter at age 23 years were all strongly correlated, suggesting that superior provenances of red spruce can be identified at age 10. The Maritimes Region can be considered as a single breeding zone for tree improvement efforts with red spruce.

Gas exchange and water relations responses to drought of fast- and slow-growing black spruce families

1997 ◽  
Vol 75 (10) ◽  
pp. 1700-1706 ◽  
Author(s):  
Weixing Tan ◽  
Terence J. Blake
Keyword(s):  
Growth Rate ◽  
Stomatal Conductance ◽  
Gas Exchange ◽  
Soil Water ◽  
Water Relations ◽  
Picea Mariana ◽  
Black Spruce ◽  
Turgor Pressure ◽  
Fast Growing ◽  
Slow Growing

To determine how different mechanisms of drought tolerance contribute to growth rate under drought, this study compared four full-sib black spruce (Picea mariana (Mill.) B.S.P.) families which differed in growth rate when soil water became limiting, stomatal conductance, photosynthesis, and water relations responses to drought. Repeated drought cycles were imposed by withholding soil water in a nursery and physiological responses were measured near the end of the first and third cycle. The most vigorous family under drought had greater osmotic adjustment and maintained higher rates of net photosynthesis during the first cycle of drought and resumed higher rates of photosynthesis sooner upon stress relief, compared with two slow-growing families. Pressure–volume analysis of drought-stressed shoot tissues indicated that the fast-growing family exhibited a larger degree of elastic enhancement (i.e., decrease in bulk modulus of elasticity), which would explain its higher turgor pressure, compared with the two less vigorous families. However, family differences in gas exchange and water relations largely diminished when seedlings were exposed to repeated cycles of drought. Therefore, fast-growing black spruce families under drought may gain selective growth advantage by a better ability to tolerate, rather than postpone, momentary dehydration. Short-term screening trials could be used to detect drought tolerant genotypes in black spruce. Key words: drought, family variation, photosynthesis, Picea mariana, stomatal conductance, water relations.

The Occurrence of Hybrid Swarms of Red and Black Spruces in Central New Brunswick

1972 ◽  
Vol 2 (4) ◽  
pp. 381-391 ◽  
Author(s):  
S. A. M. Manley
Keyword(s):  
New Brunswick ◽  
Selection Pressure ◽  
Parental Species ◽  
Black Spruce ◽  
Red Spruce ◽  
Hybrid Index ◽  
Site Preferences ◽  
Hybrid Swarms ◽  
Respective Characteristic ◽  
The Ideal

The data obtained by rating 50 plots in red × black spruce populations throughout central New Brunswick with a hybrid index indicate that red and black spruces have hybridized extensively. In the New Brunswick Lowland, gentle slopes and flat uplands form a continuum between characteristic habitats, permitting extensive contact between the two species. Where a considerable zone of contact was present, hybrid populations were established. Selection pressure is apparently strong, for despite the ideal opportunities for contact and the fertility of the hybrids, parental species remain phenotypically pure in their respective characteristic habitats (as far as these could be defined). The composition of hybrid populations was related to the extent of resemblance of 'intermediate' sites to parental site preferences. Introgressed black spruce predominated in hybrid populations, possibly due to the overriding influence of disturbances such as fire, logging, and damage to red spruce types by spruce budworm.

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