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  • Author or Editor: R. A. Larson x
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Abstract

Extended long days or interrupted night photoperiods increased leaf number and top fresh weight, and decreased tuber formation compared with short days with 2 cultivars of the “NonStop” series of tuberous begonia (Begonia X tuberhybrida Voss). Short days increased tuber size and fresh weight and reduced top fresh weight of both cultivars. ‘Double Red’ showed greater leaf number, top fresh weight, tuber fresh weight, and tuber size at 22°C than at 26°, while ‘Double Orange’ showed only greater top fresh weight at 22°. Flowering was enhanced in both cultivars under long days.

Open Access

Abstract

α-Cyclopropyl-α-(4-methoxyphenyl)-5-pyrimidinemethanol (ancymidol) applied to inherently tall-growing chrysanthemum cultivars controlled ht at concn of 62 mg/liter (0.06 mg/15 cm pot) when applied as a foliar spray, and 0.12 mg/15 cm pot when applied as a soil drench. An thesis was delayed in plants treated with high concn of the growth retardant but flower size and no., and node no. were unaffected.

Open Access

Abstract

Low light intensity caused an increase in size and a delay in flowering of gloxinias (Sinningia speciosa Benth and Hooke cv. Dwarf Delight and Royal Frosted Red). The growth regulators succinic acid-2,2-dimethyl hydrazine (SADH) and (αcyclopropyl-α-(4 methoxyphenyl)-5-prymidinemethanol (ancymidol) decreased plant size and delayed flowering. ‘Dwarf Delight’ showed damage in response to ancymidol at 250 mg/liter and higher but ‘Royal Frosted Red’ showed no damage. SADH caused a noticeable increase in anthocyanin content of the inflorescence and chlorophyll content of the leaves.

Open Access

The herbaceous perennial species in the genus Sphaeralcea have desirable drought tolerance and aesthetics with potential for low-water use landscapes in the Intermountain West. However, taxonomy of these species is ambiguous, which leads to decreased consumer confidence in the native plant nursery industry. The goal of this study was to test and clarify morphological and genetic differentiation among four putative Sphaeralcea species. Morphological characteristics of the type specimens were used as species references in canonical variate analysis to generate a classification model. This model was then used to assign putative species names to herbarium voucher specimens and to field-collected voucher specimens to clarify genetic variation among species. Field specimens were also classified using Bayesian cluster analyses of amplified fragment length polymorphism (AFLP) genotypes. Sphaeralcea coccinea (Nutt.) Rydb. and S. grossulariifolia (Hook. & Arn.) Rydb. formed a composite group morphologically and genetically distinct from the S. munroana (Douglas) Spach and S. parvifolia A. Nelson composite group. Each composite group displayed genetic isolation by geographic distance. Also, morphological traits of S. munroana and S. parvifolia correlated to geographic distance. Taken together these results suggest that our samples represent two sympatric yet reproductively isolated groups. Distinguishing between these two Sphaeralcea composite groups can create greater consumer confidence in plant material developed for use in Intermountain West low-water landscaping.

Free access

Shepherdia rotundifolia Parry (roundleaf buffaloberry), a shrub endemic to the U.S. Colorado Plateau high desert, has aesthetic and drought tolerance qualities desirable for low-water urban landscapes. However, slow growth and too often fatal sensitivity to wet or disturbed soil stymies nursery production and urban landscape use. The goal of this study was to create an interspecific hybrid between the evergreen-xeric S. rotundifolia and its widely adapted, fast-growing, deciduous relative Shepherdia argentea (silver buffaloberry) distributed in western North America riparian habitats. Genetics and leaf morphology of the resulting S. argentea × S. rotundifolia hybrid are described and compared with the parents, as well as hybrid gas exchange as a reasonable proxy for growth rate and potential tolerance of poor soil. Hybrid genotypes were heterogenous, but contained an intermediate and equal contribution of alleles from genetically heterogenous parent populations. Leaf morphology traits were also intermediate between both parents. Aesthetic leaf qualities (silver-blue color and revolute margins) sought from S. rotundifolia were conserved in all offspring. However, gas exchange responses varied widely between the two surviving hybrids. Both hybrids showed greater tolerance of wet, fertile substrate—and promise for use in low-water landscapes—than S. rotundifolia. However, one hybrid conserved faster growth, and by inference possibly greater tolerance of wet or disturbed soil, from S. argentea, while the opposite was observed in the second hybrid. Following botanical nomenclature, we named this hybrid Shepherdia ×utahensis.

Free access