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Abstract
Rapid clonal multiplication of Cephalotus follicularis Labill. was achieved on 1/2 strength Linsmaier-Skoog medium with 30 g/liter sucrose and 8 g/liter agar. Shoot tip cultures were started on a medium supplemented with 0.1 mg/iiter indolebutyric acid (IBA) and 1.0 mg/liter benzyl adenine (BA), which best stimulated growth, and kept in darkness the first 6 weeks. After 2 more months in constant light they were subcultured to a medium with 0.1 mg/liter naphtahaleneacetic acid (NAA) and 0.1 mg/liter BA that induced rapid proliferation. A 5-10 fold increase in plant material was achieved after each subculture.
Abstract
Rapid clonal multiplication of Pinguicula moranensis H.B.K., an “orchid-flowered” butterwort, was achieved on 1/5-strength Linsmaier-Skoog medium with 30 g/liter sucrose, pH 6.5, 6 g/liter agar, 0.02 mg/liter 6-benzylamino purine (BA), and 0.01-0.10 mg/liter naphthaleneacetic acid (NAA).
Sixty clones (four clones from each of 15 provenances) were micropropagated and planted in replicated plots in lowland and upland sites in Carbondale, IL in 1991. Data were collected on tree growth, including basal caliper, height, branching, crown volume, dates of bud break, bud set, and leaf fall. There were significant and strong positive genotypic and phenotypic correlations between tree height and basal caliper throughout the three years of growth. During 1993, bud break was not significantly correlated with any growth parameters. After three years in the field, tree height was significantly negatively correlated with the amount of callus that had formed after one month during the in vitro micropropagation phase. However, all shoots that formed in vitro were of axillary origin.
The ability of certain apple rootstocks to dwarf their scions has been known for centuries and their use revolutionized apple (Malus ×domestica) production systems. In this investigation, several apple rootstock breeding populations, planted in multiple replicated field and pot experiments, were used to ascertain the degree of dwarfing when grafted with multiple scions. A previous genetic map of a breeding population derived from parents ‘Ottawa 3’ (O.3) and ‘Robusta 5’ (R5) was used for quantitative trait locus (QTL) analysis of traits related to scion vigor suppression, induction of early bearing, and other tree size measurements on own-rooted and grafted trees. The analysis confirmed a previously reported QTL that imparts vigor control [Dw1, log of odds (LOD) = 7.2] on linkage group (LG) 5 and a new QTL named Dw2 (LOD = 6.4) on LG11 that has a similar effect on vigor. The data from this population were used to study the interaction of these two loci. To validate these findings, a new genetic map comprised of 1841 single-nucleotide polymorphisms was constructed from a cross of the dwarfing, precocious rootstocks ‘Geneva 935’ (G.935) and ‘Budagovsky 9’ (B.9), resulting in the confirmation and modeling of the effect of Dw1 and Dw2 on vigor control of apple scions. Flower density and fruit yield data allowed the identification of genetic factors Eb1 (LOD = 7.1) and Eb2 (LOD = 7.6) that cause early bearing of scions, roughly colocated with the dwarfing factors. The major QTL for mean number of fruit produced per tree colocated with Dw2 (LOD = 7.0) and a minor QTL was located on LG16 (LOD = 3.5). These findings will aid the development of a marker-assisted breeding strategy, and the discovery of additional sources for dwarfing and predictive modeling of new apple rootstocks in the Geneva® apple rootstock breeding program.