The genus Cyclamen is a member of the Primulaceae, yet speciation of individual members can be confusing. Cyclamen are very diverse, with several species widely distributed throughout the Mediterranean countries and others indigenous only to specific islands or mainland areas (2, 3). Their foliage is extremely variable. Within a single species leaves may range from orbicular to cordate with entire to dentate margins, and with or without gradations of silver-gray zonal patterns. Flowers may be scented or odorless and range in color from white to deep pink. They either precede or arise after the foliage and reach anthesis during autumn, winter or spring (3, 10). The species persicum is uniquely different in that its fruited peduncles haphazardly bend and twist instead of coiling back to the crown. The coiling may facilitate seed dispersal by ants, but C. persicum has lost the coiling characteristic even though it shares this dispersal vector (5).
Seven Streptocarpus × hybridus Voss. cultivars were grown from seed and compared on the basis of 9 vegetative and flowering characteristics. Although differences were found within cultivars for most parameters, ‘Concorde’, ‘Ofai’, and ‘Nymph’ tended to flower the earliest with the shortest time lapse between anthesis of the 1st and 3rd peduncle. ‘Wiesmoor’ and ‘Splendid’ exhibited delayed flowering of all 3 peduncles and had significantly increased leaf size at 1st flower, whereas ‘Large Flower Mix’ and ‘Mauser's Riesen’ displayed intermediate responses. Cluster analysis identified ‘Concorde’, ‘Ofai’, and ‘Nymph’ as moderately uniform, and the remaining cultivars as heterogeneous. The degree of cultivar homogeneity was taken as an indication of the potential for seed propagation of this greenhouse pot plant.
As the concentration of the exogenously applied gibberellin GA4+7 increased from 1 to 100 ppm, 3 significant correlations were observed: 1) the number of days to first flowering decreased; 2) the peduncle length of the first flower increased; and 3) the number of visible peduncles on the primary phyllomorph increased. A subsequent application of 10 ppm naphthaleneacetic acid (NAA) generally had no effect on these results.
In the article “Relationship between GA Application and Phyllomorph Length in Streptocarpus” by R.E. Lyons, R.E. Veilleux, and J.N. Booze-Daniels [Journal 10(5):647–650, 1985] the figure captions were reversed. The correct figures and captions appear below.
Limb applications of 5% or 10% alkaryl polyoxyethylene alcohols (X-77 or X- 45) caused flower bud removal when applied to peach trees [Prunus persica (L.) Batsch] with a hand pump sprayer from first pink to 90% bloom. Applications made in late pink or bloom period caused a greater reduction in fruit set than earlier treatments. Applications made at 90% bloom caused some phytotoxicity to the tips of the first small leaves but did not affect the growth of the terminal vegetative primorida or of larger leaves produced on later terminals. Thinning appeared to be commercially acceptable when applied between 30% and 90% bloom. Fruit size at harvest was greater than the unthinned control. Airblast applications of 10% X-77 on the ‘Loring’ cultivar reduced fruit set about 40%.
Mechanical and chemical methods for improving the branching of Crassula argentea Thunb., Kalanchoe tomentosa Bak., and Columnea microphylla Klotzsch and Hanst. ex Orst. were examined. C. argentea did not respond to hand-pinching, atrinal, or BA treatments. K. tomentosa produced 44% more branches when treated with 50 ppm BA but were relatively unaffected by atrinal or hand-pinching. C. microphylla typically branched only from the basal nodes; however, 59% more branching was observed when treated with 500 ppm atrinal. Hand-pinching or BA did not affect branching of Columnea. Atrinal also retarded stem elongation of C. microphylla; the inhibitory effect of 500 ppm was comparable to the reduction in stem length caused by hand-pinching. Chemical names used: (2,3:4,6 bis-O-(1-methylethylidene)-O-L-xylo-2-hexulofuranosonic acid, dikegulac sodium, atrinal), N-(phenylmethyl)-2H-purin-6-amine (BA).
Airblast applications of ammonium nitrate, ammonium thiosulfate, an oxylated alcohol surfactant (SN-50), or 7-oxabicyclo-(2,2,1) heptane-2,3-dicarboxylic acid (endothall) to peaches [Prunus persica (L.) Batsch] in bloom reduced fruit set and increased fruit size on several cultivars. Foliage injury was minimal when applied at bloom. Applications of these chemicals 6 days post-bloom to ‘Redhaven’ trees caused unacceptable foliage injury and did not cause fruit abscission. Several other surfactants and fertilizers were found to have caustic action in laboratory trials, but fruit set on ‘Redhaven’ was not reduced in field airblast trials.
Gaillardia × grandiflora Van Houtte ‘Dazzler’ and ‘Goblin’ were induced to flower under long days. Applications of GA4+7 (GA) substituted for long days and promoted flowering under short days in the same amount of time required by untreated, photoperiodically induced plants. Although cultivar and photoperiod dependent, GA also increased scape length and reduced scape caliper, flower head diameter and ray floret number. Leaf production was accelerated by several weekly applications of GA.
Airblast application of fertilizers, desiccating herbicides, or surfactants reduced fruit set and increased fruit size of ‘Redhaven’ peach [Prunus persica (L.) Batch]. The addition of the surfactant, aikylaryl polyoxyethylene glyco phosphate ester (Spray Aide), to ammonium thiosulfate (ATS) at rates from 0 ml/liter to 5 ml/liter did not increase thinning. When rates of ATS/ha remained constant, water volumes from 2338 Iiter/ha to 420 liter/ha did not affect thinning. Forty-six percent to 62% more flower buds developed on twigs from chemically thinned trees than on hand thinned trees. Most of this flower bud increase was on the 5 basipetal nodes of current season shoots. Treatment of the stigma, petals + anthers, peduncle, or calyx with ATS reduced fruit-set. Necrotic regions in the peduncle of some flowers could be seen under a microscope 48 hr after treatment. Flowers sprayed with DuPont WK or NH4NO3 + X-77, plus methylene blue (added as a tracer) had blue dye in the veins of the calyx, pedicle, and peduncle of some flowers after 24 hr.
Rudbeckia hirta ‘Marmalade’, a long-day (LD) plant, required a minimum of 4 LD for flower initiation. Continuation of LD photoperiods beyond the minimum cycle number was essential for normal growth and development. Plants that received only enough LD for floral initiation were half as tall and flowered significantly later than plants held in LD for the entire experiment. Limited periods of LD were much more effective than soil applications of up to 50 ppm ancymidol for height control, and 50 ppm ancymidol delayed flowering. Chemical name used: α-cyclopropyl-α-(4-methoxyphenyl)-5-pyrimidinemethanol (ancymidol).