Somatic Embryogenesis in Picea Glauca (white spruce), P. engelmannii (Engelmann spruce) and P. glauca engelmannii complex (interior spruce)

Author(s):  
S. M. Wilson ◽  
T. A. Thorpe
2006 ◽  
Vol 84 (7) ◽  
pp. 1129-1141 ◽  
Author(s):  
W.L Strong ◽  
L.V. Hills

White spruce ( Picea glauca (Moench) Voss) and Engelmann spruce ( Picea engelmannii Parry ex Engelm.) seed-cones from 676 sites in Canada and the northern United States were analyzed to determine the degree and spatial extent of interspecific hybridization. Fifteen cone-scale variables were analyzed, with percent free-scale and scale shape considered best for differentiating these taxa. The results show that putative Engelmann spruce and their hybrids occur mostly in the vicinity of the Rocky Mountains. Putative white spruce occurs across Canada east of the Rocky Mountains, whereas white × Engelmann hybrids occur eastward to Manitoba and northward to 68° latitude in northwest Canada. To explain the occurrence of the latter taxon hundreds of kilometres from an Engelmann spruce pollen source, it is hypothesized that palaeohybridization occurred during the Wisconsinan glacial period, probably in the southern Montana – Wyoming – Black Hills (South Dakota) region, with the resulting hybrids spreading north and northeastward into interior Canada following the retreat of the Laurentide glacier. White and Engelmann spruce have morphologically distinct cone-scales, whereas their hybrids have intermediate characteristics. An emended species ( Picea albertiana ) and two subspecies (P. albertiana subsp. albertiana and P. albertiana subsp. ogilviei) are proposed to account for morphological intermediates between the parent species.


1977 ◽  
Vol 198 (1133) ◽  
pp. 325-344 ◽  

In Picea glauca , the White Spruce, supernumerary, B chromosomes were found in 48 out of 51 North American populations investigated. The B chromosomes are of two kinds. The more common (B1) is metacentric. The other (B2) has a subterminal centromere. Giemsa staining at metaphase shows no trace of constitutive heterochromatin in B chromosomes, yet at interphase the B chromosomes are heteropycnotic. It is argued that the capacity for heterochromatization of the B chromosomes at interphase may be associated with gene inactivation as in the X chromosomes of female mammals. B2 is found in western regions only, i. e. west of the 95th meridian. B1 is found in both western and eastern regions but its frequency varies substantially among populations. In general there is a reduction in B frequency from east to west in both western and eastern regions of North America. Experimental results support the view that such variation is adaptive and, in part at least, caused by the differential mortality of plants with and without B chromosomes in particular environments. Evidence is presented which indicates that B2 was introduced into White Spruce following hybridization with Engelmann Spruce.


2011 ◽  
Vol 5 (S7) ◽  
Author(s):  
Krystyna Klimaszewska ◽  
Brian Boyle ◽  
Sebastien Caron ◽  
Don Stewart ◽  
Catherine Overton ◽  
...  

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