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  • Author or Editor: Suman Singha x
  • HortScience x
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Abstract

Shoot tips of ‘Almey’ crabapple [Malus baccata (L.) Borkh. × M. pumila var. niedzwetzkyana (Dieck) Schneid.] and ‘Seckel’ pear (Pyrus communis L.) were cultured on Murashige and Skoog (MS) medium containing 2 mg/liter 6-benzylamino purine (BA). The culture medium contained either TC agar or Bacto-agar at concentrations ranging from 0% to 1.2%. Optimum shoot proliferation in ‘Almey’ was obtained on media containing 0.3% of either agar. Increasing agar levels reduced shoot proliferation and shoot growth, but the reduction was especially severe with Bacto-agar. The differences in shoot proliferation between the 0.3% and 0.6% agar concentrations continued to be exhibited with Bacto-agar but not with TC agar when Mason jars, rather than 25 × 150-mm tubes, were the culture vessels. Shoot proliferation in ‘Seckel’ was best on medium containing 0.6% Bacto-agar; higher concentrations decreased shoot proliferation and shoot growth. TC agar did not influence fresh weight of ‘Seckel’ cultures, but increasing concentrations resulted in increased shoot proliferation.

Open Access
Author:

Abstract

Rapid propagation of crabapple (Malus spp.) cultivars was achieved in vitro. Proliferation of shoot tips was induced on Murashige and Skoog (MS) medium containing 6-benzylamino purine (BA). Rapid shoot proliferation was obtained at 1 or 2 mg/liter BA. Higher levels (4 or 8 mg/liter) resulted in good shoot proliferation, but a greater percentage of shoots were small or rosetted. Rooting was achieved by transferring individual shoots to MS medium containing naphthaleneacetic acid (NAA). Low NAA levels (0.1 or 0.2 mg/liter) resulted in good root development. Plantlets were successfully transferred to soil.

Open Access

Shoots of `Almey' crabapple [Malus baccata (L.) Borkh. × M. pumila var. niedzwetzkyana (Dieck) Schneid.], `Seckel' pear (Pyrus communis L.), and `Mrs. Bradshaw' geum (Geum quellyon Sweet.) were cultured on Murashige and Skoog (MS) medium supplemented with 8.8 μm BA and containing 0.1% to 0.4% Gelrite. Comparative shoot proliferation and vitrification were determined on Phytagar-solidified medium. Shoot proliferation, culture fresh weight, and vitrification declined in crabapple and geum with increasing Gelrite concentration. Pear proliferation and fresh weight increased with increasing Gelrite levels, but all shoots were vitrified. There were differences in the vitrification response between pear and the other two genera. The percent dry weight of vitrified cultures on Gelrite-containing media was generally higher than that of nonvitrified cultures on medium containing Phytagar. Vitrification precludes using low Gelrite concentrations for propagating these plants. Chemical name used: N-(phenylmethyl) -1H-purin-6-amine (BA).

Free access

Differences in color development between exposed and shaded fruit during the growing season were determined for `Loring' and `Raritan Rose' peach (Prunus persica L. Batsch). The surface color of fruit exposed to sunlight in the upper canopy, and in the shade in the lower canopy, was measured with a tristimulus calorimeter, and L* a* b* values were recorded for each fruit from 17 July through harvest. Color changes (ΔE* ab) during maturation for both cultivars at either canopy position were characterized by large changes in hue (Δ H*ab) and lesser changes in lightness (Δ L*ab) and chroma (Δ C*ab). Upper canopy fruit of both cultivars were redder and darker than the lower canopy fruit initially and at harvest. Flesh firmness for `Loring' and `Raritan Rose' tended to correlate with color change from initial sampling to harvest.

Free access

Fruit of 34 peach (Prunus persica L. Batsch). cultivars were harvested at maturity and visually evaluated by panelists on a 1 to 10 scale, where 10 = excellent color. CIELAB coordinates (L* a* b*) of fruit color were measured at the midpoint between the stem and the calyx end with a Minolta CR-200b calorimeter on the blushed and ground areas of each fruit. Simple linear regressions of color coordinates with panel ratings indicated that blush chroma, blush L*, blush hue angle and E* (total color difference between ground and blush) all influence visual color evaluation. Not only does assessing fruit color with a calorimeter permit color to be reported in internationally accepted units, but the relationships indicate that instrumental values relate well to qualitative ratings.

Free access

Variations in the pattern of fall color development in the leaves of Acer rubrum, Acer saccharum, Quercus coccinea, Oxydendrum arboreum and Euonymus alatus were determined. CIELAB coordinates were measured with a Minolta CR-2000b calorimeter at a marked location on 5 tagged leaves from 2 plants of each species. The changes in hue follow similar trends in these species, but the time of onset varies. Onset of red color development increased variability in hue between leaves of the same species. Based on color changes in E. alatus anthocyanin development occurs prior to significant loss of chlorophyll and red coloration remains masked, whereas in A. rubrum anthocyanin development occurs in association with or following the loss of chlorophyll. This results in differences in the pattern of hue and chroma development between these species.

Free access