High subculture frequency, maltose-based and hormone-free medium sustained early development of somatic embryos in maritime pine

Simple and efficient protocols for the initiation and proliferation of embryogenic tissue of Douglas-fir

“…In Scots pine SEs, the size of the embryo increased when maltose was used instead of sucrose in MSG and DCR media (Keinonen-Mettala et al 1996). In maritime pine, maltose was found to slightly improve early SE development when used instead of sucrose in DCR medium (Breton et al 2005) (Fig. 2).…”

“…Durzan and Gupta (1987) found that Douglas-fir embryonalsuspensor masses (ESMs) turned into calli when subculture was delayed to more than 15 days. In maritime pine, it was also reported that weekly subcultures rather than bi-weekly were required to delay the "ageing" of embryogenic cultures, which became unproductive, non-embryogenic versions of original lines (Breton et al 2005). It is possible that callus is derived from differentiating embryo initials that reach a point of development where they cease cleavage polyembryony but have insufficient environmental stimuli (for example, abscisic acid) to continue differentiating.…”

Cotyledonary somatic embryos of Pinus pinaster Ait. most closely resemble fresh, maturing cotyledonary zygotic embryos: biological, carbohydrate and proteomic analyses

“…Extensive research on various steps in the process has since been undertaken in France (Ramarosandratana et al 2001;Breton et al 2005; Lelu-Walter et al 2006), Portugal (Miguel et al 2004), and Spain (Humánez et al 2012). Improved protocols are now available for stages ranging from the initiation and proliferation of embryogenic tissue (Park et al 2006) to somatic plant regeneration .…”

Somatic Embryogenesis for More Effective Breeding and Deployment of Improved Varieties in Pinus spp.: Bottlenecks and Recent Advances

“…Cultures on mLV consistently produce high initiation rates in maritime pine (Table 19.1) with both French Trontin et al 2016a) and Spanish (Humánez et al 2012) seed families. In maritime pine, comparison of DCR (Gupta and Durzan 1985) and modified DCR (Breton et al 2005) (mDCR) in a parallel experiment revealed that SE initiation rates were reduced by approximately 50 % compared with mLV. The data, based on a large selection of full-or half-sib seed families, showed that the mean initiation rate was 67.5 % on mLV and only 23.3 % on mDCR (Trontin et al 2016a).…”

“…Bars represent 95 % confidence limits. For each sampling date (N = 36-90 cotyledonary se), significant variation between means (t-tests, α = 0.05) is indicated by different letters maltose instead of sucrose and no PGR (Breton et al 2005). For the time being, cryopreservation is still necessary to retain young clones of initiated lines until alternative culture conditions are discovered to overcome the ageing problem.…”