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- Author or Editor: M. Stevens x
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Abstract
The instrumentation required for objective evaluation of flavor has been available for only a decade and a half. Most information on the chemistry of flavor has accumulated within the past 5 years. There have been few studies on intercultivar variation of compounds important to flavor. Because an appreciation of the physiology of flavor and an understanding of flavor chemistry are basic to the genetics of flavor, it seems appropriate to discuss briefly these topics.
Abstract
Chrysanthemum morifolium Ramat. cv. Sunny Mandalay plants were grown in hardwood bark media amended with various levels of insoluble poly (ethylene oxide) (Viterra Hydrogel, VH). Plants grown in rates ranging from 57–454 g/0.03 m3 required less watering, had increased shelf life, and exhibited no phytotoxicity.
Abstract
Growth of Chrysanthemum morifolium Ramat was evaluated in ground pine bark:sand mixes; a soil:peat:perlite mix; and commercially mixed media. Flowering stem:dry weight of plants grown in barkrsand (3:1 or 2:1, by volume) were comparable to commercial mixes but 100% pine bark or soil:peat:perlite significantly reduced plant height and flowering stem dry weight.
The rulings that utility patents can be granted for plant varieties has had a profound effect on the research agendas of seed companies. Although there is confusion on utility patents, most major seed companies are concerned about how they will affect their competitive position. Strategic alliances are common; these may involve a seed company (germplasm resources) and a biotechnology company (gene constructs). Licensing agreements are frequently used to access new technologies and genes. Material transfer agreements are being used to access genes for proof of concept studies. Commercial agreements have thus far been elusive. Seed companies strongly favor revision of the Plant Variety Protection Act to conform to the 1991 International Union for the Protection of New Varieties of Plants (UPOV) Convention.
Abstract
This article provides a short-short course in gas chromatography, beginning with principles and ending with procedures for separations in the major classes of compounds of interest to horticulturists.
Abstract
Traditionally, plant breeders have been concerned with haracteristics such as yield and disease resistance which can be evaluated subjectively or by straightforward objective methods where differences are qualitative and maximum manifestation of the trait is desired. Quality has not been a principal objective in most plant breeding programs; frequently, it has been an afterthought. Once the other desired characteristics have been achieved, there is an attempt to select for adequate quality. The attention that quality characters have received varies greatly among the numerous quality traits. Color, for example, has received considerable attention because of its importance to appearance and consequently salability. In contrast, nutritional value and flavor have been mainly neglected by plant breeders.
Seeds of two tepary bean lines (Phaseolus acutifolius Gray var. latifolius) and one navy bean cultivar (P. vulgaris L. `Fleetwood') were tested with 0.0-, – 0.3-, –0.6-, -0.9-, -1.2-, or – 1.5-MPa NaCl solutions to determine their relative salt tolerance during germination and emergence. Developmental stage was not affected at – 0.3 MPa, but with salinities more negative than -0.9 MPa, `Fleetwood' developed more slowly than the tepary lines; no plants emerged at – 1.5 MPa. Teparies tended to maintain higher water and osmotic potentials than navy over the range of NaCl concentrations used, although turgor was similar for all three genotypes. Leaf area was reduced more in navy than in white tepary at – 0.6 and – 0.9 MPa. Dry weights of navy were higher than those of either tepary bean at all NaCl concentrations, although decreases at higher salinities relative to 0.0 MPa were greater for navy than for teparies. Root: shoot ratios were higher at – 0.3 MPa than at 0.0 MPa, but were lower at the higher NaCl concentrations for all three genotypes. Overall, tepary beans tolerated NaCl better than navy. The characteristic that best indicated differences in salt tolerance was developmental stage.
The regulation of anther dehiscence by relative humidity (RH) was assessed for detached anthers and detached whole flowers from a limited selection of apricot (Prunus armeniaca L.), peach [P. persica (L.) Batsch], and almond [P. dulcis (Mill.) D.A. Webb, syn. P. amygdalus Batsch; P. communis (L.) Arcangeli, non Huds.] genotypes, as well as an almond X peach F2 progeny. Dehiscence was evaluated at 33, 64, 87, 93 and 97% RH for detached anthers, and at 33, 64 and 97% RH for whole detached flowers. Anther dehiscence was suppressed with increasing RH for all genotypes. Apricot anthers showed the greatest dehiscence at low RH and measurable dehiscence at high RH even when detached. Anther dehiscence in almond appeared more suppressed than in apricot at all RH levels tested, being completely suppressed by high RH in detached anthers. Peach genotypes exhibited the full range of variability between apricot and almond patterns. Evidence for transgressive segregation of RH-controlled anther dehiscence was observed in the occurrence of cleistogamy in an almond × peach F2 progeny. Rates of anther dehiscence were approximately linear with change in RH in detached anthers but exhibited a more buffered, step-wise response when detached whole flowers were tested. Results are consistent with field observations, and highlight the low but measurable risk of cleistogamy in these species, as well as opportunities to modify the breeding systems and crossing environments to facilitate controlled hybridization, and to reduce pollination vulnerability to adverse environments.