Challenges facing Chamaecyparis nootkatensis seed orchards: low seed production, pollen-cone abortion, self-pollination, and accelerated embryo development

Abstract

Seed orchard production of Chamaecyparis nootkatensis (D. Don) Spach seed faces several challenges including low seed production, pollen-cone abortion, self-pollination, and accelerated reproductive development. In a seed orchard study in 1988 and 1989, approximately eight seeds were produced per cone, but only one to three seeds per cone contained viable embryos. Pollen-cone abortion in 21 clones ranged from 6 to 87% in 1989–1990 and from 0 to 6% in 1990–1991. A bud mite, identified as Trisetacus chamaecypari Smith, was consistently associated with pollen-cone abortion in two orchard locations. This mite may be the cause or simply a symptom of unhealthy pollen cones. In a pollination study involving wind, self, and cross pollinations on five clones, self-pollinated cones had significantly fewer seeds containing embryos (4%) compared with the other treatments (28–33%). Pollen-cone development at a seed orchard occurred in July and August 1990 and was comparable with natural stand phenology. However, embryo development was significantly accelerated, with embryos at a seed orchard substantially larger than embryos at the natural stand at comparable times.

Whitebark pine (Pinus albicaulis Engelm.) seed production in natural stands

“…The possible causes for the various types of seeds were determined from earlier studies of cone, seed and embryo development in other conifers (Dogra, 1967;Owens et al, 1990Owens et al, , 1991Owens et al, , 1994Owens, 1993;Owens and Morris, 1998;Anderson et al, 2002) including pines (Owens and Molder, 1997b;Owens et al, 1982Owens et al, , 2005Owens, 1993;Owens and Fernando, 2007).…”

Multisite genetic parameter estimates from aCallitropsis nootkatensisdiallel study with clonally replicated progeny

“…However, for the C. nootkatensis economic traits measured in this study, the incremental gain that is attainable from nonadditive genetic variances would be minimal. Thus, the additional cost of deploying clones would not be justifiable, except that seed orchards are not a viable option at this time due to a number of factors affecting viable seed production (Anderson et al 2002). Additionally, the current C. nootkatensis clonal program in BC has delivered a gain of >20% in volume at rotation, far in advance of attaining elite seed from an orchard, a commonly stated advantage of clonal deployment (Matheson and Lindgren 1985;Shelbourne 1992;Rosvall et al 1998).…”

“…Little (yellow cypress), an ecologically and economically important coastal montane species in the Pacific Northwest and in British Columbia (BC), has a long and variable reproductive cycle, as well as a low seed viability, especially in off-site seed orchard settings (Owens and Molder 1974, 1975, 1977El-Kassaby et al 1991;Pawuk 1993;Anderson et al 2002;Hak and Russell 2004). However, the species has a high level of clonality in wild stands (Thompson et al 2008), which occurs normally through branch layering.…”

“…Therefore, the use of rooted cuttings is considered a viable option for reforestation (Karlsson and Russell 1990;Russell 1992). Given the lack of orchard seed production of C. nootkatensis (Anderson et al 2002), a breeding strategy involving field testing of cloned progeny from partial diallels was implemented in BC (Russell 1992). This strategy controls pedigree, thus providing deployment flexibility and ensuring acceptable diversity levels, as well as providing higher accuracy of forward selections based on additive genetic effects (Shaw and Hood 1985;Shelbourne 1992;Russell and Loo-Dinkins 1993).…”

Growth and development of conifer pollen tubes

“…In culture, pollen germination occurs after 1 or 2 days in Thuja plicata (Colangeli and Owens 1990a), Tsuga heterophylla (Colangeli and Owens 1990b), Picea glauca (Dawkins and Owens 1993), Larix occidentalis , Pseudotsuga menziesii (Webber and Painter 1996;Fernando et al 1997), Taxus brevifolia (Anderson and Owens 2000), Chamaecyparis nootkatensis (Anderson et al 2002), Abies amabilis (Chandler and Owens 2004), and Pinus contorta (Owens et al 2005). Although pollen germination in conifers is slow, they are generally easy to germinate in vitro and a very high germination percentage has been reported in various groups especially in Pinus.…”