Micropropagation of Lowbush Blueberry from Mature Field-grown Plants

Bud cultures from nonjuvenile field clones of lowbush blueberry (Vaccinium angustifolium Ait.) were established on Z-2 medium with 59 μm 2iP. Reversion to juvenile characteristics with small and rounder leaves occurred only on two explants after 19 weeks in culture. These shoots grew vigorously and could be easily subcultured. The number of shoots of one clone doubled every 23.3 days. Reducing the 2iP concentration to 12.3 and 24.6 μm reduced shoot proliferation, but permitted better shoot elongation. After 5 weeks in a mix of 3 peat: 2 vermiculite: 1 perlite, shoots >20 mm rooted better than shoots measuring 10 to 20 mm. Chemical names used: N-(3-methyl-2-butenyl)-1-H-purine-6-amine (2iP); 1H-indole-3-acetic acid (IAA)

Elongation, rooting and acclimatization of micropropagated shoots from mature material of hybrid larch

Factors were defined for elongation, rooting and acclimatization of micropropagated shoots of Larix x eurolepis Henry initiated from short shoot buds of plagiotropic stecklings serially propagated for 9 years from an 8-year-old tree. Initiation and multiplication were on Schenk and Hildebrandt (SH) medium supplemented with 5 μM 6-benzyladenine (BA) and 1 μM indole-butyric acid (IBA). Stem elongation was obtained in 36% of the shoots on SH medium containing 0.5 μM BA and 63% of the remaining non-elongated shoots initiated stem elongation after transfer on SH medium devoid of growth regulators. Rooting involved 2 steps: root induction on Campbell and Durzan mineral salts and Murashige and Skoog organic elements, both half-strength (CD-MS/2), supplemented with 1 μM of both naphthaleneacetic acid (NAA) and IBA, and root elongation following transfer to CD-MS/2 medium devoid of growth regulators. Repeating this 2-step sequence yielded up to 67% rooted shoots. Acclimatization of plantlets ranged from 83% to 100%. Over 300 plants were transferred to the greenhouse; some showed plagiotropic growth