Flower color preference of western flower thrips [WFT (Frankliniella occidentalis) (Thysanoptera: Thripidae)] was assessed by observing insect location after introduction into chambers containing four different colored flowers of each of three plant species: transvaal daisy (Gerbera jamesonii), matsumoto aster (Callistephus chinensis), and chrysanthemum (Dendranthema ×grandiflorum). Preference was based on the number of WFT adults found on each flower 72 hours after infestation. Significantly higher numbers of WFT were found on yellow transvaal daisy and yellow chrysanthemum. When these accessions were compared in a subsequent experiment, WFT displayed a significant greater preference for the yellow transvaal daisy. Visible and near infrared reflectance spectra of the flowers used in the study were measured to determine the presence of distinct spectral features that would account for the relative attractiveness of the flowers. Likewise, the reflectance spectra of three commercially available sticky cards (blue, yellow, and yellow with a grid pattern) that are used to trap or sample for WFT were compared to those of the flowers to determine any shared spectral features that would support observed WFT flower color preference. The observed similarity between the yellow transvaal daisy and yellow sticky card reflectance spectra supports the hypothesis that flower color contributes to attractiveness of WFT. In particular, the wavelengths corresponding to green-yellow (500 to 600 nm) seem to be responsible for attracting WFT. These findings also indicate that yellow sticky cards may be more appropriate in sampling for WFT than blue sticky cards. Although further research is needed, under the conditions of this study, yellow transvaal daisy appears to be a potentially useful trap crop for WFT.
Meredith R. Blumthal, L. Art Spomer, Daniel F. Warnock, and Raymond A. Cloyd
Pei-Wen Kan, Yu-Ching Cheng, and Der-Ming Yeh
color in caladium cultivars. The locus has been designated as V and the order of dominance is V r (red vein) > V w (white vein) > V g (green vein) ( Deng and Harbaugh, 2006 ). No information regarding the inheritance of the white vein in gloxinia
Ryan N. Contreras, John M. Ruter, and David A. Knauft
wild-type color is metallic-purple to magenta but there are cultivars with white (‘Lactea’ and ‘Bok Tower’) and pink (‘Welch’s Pink’) fruit, both of which are rare in nature. There are also leaf-variegated forms of American beautyberry such as ‘Berries
Huicong Wang and Lailiang Cheng
, increasing N supply leads to larger fruit and higher soluble solids in ‘Gala’ apple ( Xia et al., 2009 ). However, red-fruited cultivars grown under high N supply often have poor color. The intensity and extent of coloration is an important consideration in
Bernard B. Bible and Richard J. McAvoy
Forty-two poinsettia cultivars were grown as a 15-cm single-plant pinched crop at 21/16.5°C (day/night) temperatures during Fall 1995 with standard commercial practices for irrigating, fertilizing, and pest control. On 7 Dec., 156 consumers rated the cultivars for their overall appeal. On 11 Dec., color coordinate (CIELAB) readings for bracts and leaves were taken with a Minolta 200b colorimeter. The colorimeter was set to illuminate C and has a 8-mm aperture. Bracts and leaves were placed on a white tile background for colorimetric readings. In 1996, a similar evaluation was conducted with 55 poinsettia cultivars. Using the L-value of leaves as a criterion, cultivars were separated into medium green-leafed and dark green-leafed groupings. For bracts among the red types, hue angle values were used to separate cultivars into cool red types (hue angle ≈20–22°) and warm red types (hue angle ≈24–25°). Based on the 1995 study, cultivars within the cool red bracts and dark green foliage group—those that were darker, duller red (lower L and chroma)—were less attractive (lower consumer ratings) than lighter, more-vivid red cultivars. For cultivars within the cool red bracts and medium green foliage group, consumers preferred the darker duller red cultivars. Perhaps dark foliage gives a more pleasing contrast with the more vivid cool reds than does the medium green foliage. In general, consumers rated red cultivars hire than non-red cultivars.
Jonathan Dixon and Errol W. Hewett
Loss of green color (yellowing) in apples (Malus ×domestica Borkh.) is due to chlorophyll breakdown, an enzyme-mediated reaction conforming to first-order kinetics. Nondestructive measurements of yellowing, using a tristimulus chromameter, were related to chlorophyll content for `Cox's Orange Pippin' and `Granny Smith' apples stored at temperatures of 0 to 35 °C. Yellowing determined by rate constant (k) of total chlorophyll and changes in hue angle, as a function of temperature, increased slowly from 0 to 5 °C, increased exponentially from 5 to 20 °C, reached a maximum from 20 to 24 °C, then declined at higher temperatures. Values of k and the rate of change of hue angle were characterized by a modified Arrhenius equation. `Cox's Orange Pippin' apples harvested early had lower k and lower rates of hue angle change than late-harvested fruit. Values of k and hue angle change of `Granny Smith' apples differed between years but not between harvests. The method used to characterize the relationship between yellowing and temperature may describe changes in other important quality attributes of apple fruit during storage and shelf life and help evaluate the efficacy of cool-chain handling and storage systems.
Matthew R. Mattia and John W. Scott
be the least prone to YS. It is also important to know if there is a general trend for higher SSC to be associated with green shoulder vs. u and/or other fruit color genotypes as this would suggest a breeding shift back to u + to attain better
Ji Tian, Ke-ting Li, Shi-ya Zhang, Jie Zhang, Ting-ting Song, Yong-jun Zhu, and Yun-cong Yao
color is a key determinant of the commercial value of many ornamental plant species, and Malus crabapples varieties show a diverse range of leaf, flower, and fruit and leaf colors. There are three kinds of Malus crabapples leaf-color cultivars
Gerry Henry Neilsen, Denise Neilsen, and Linda Herbert
long established, from broadcast N fertilization studies, that increasing the rate of N application can increase yield but adversely affect fruit quality by decreasing fruit color and firmness ( Oberly and Boynton, 1966 ). Much less information is
Zhe Cao, Shunzhao Sui, Qian Yang, and Zhanao Deng
hybridizations between elite cultivars or breeding lines. In recent years, significant efforts have been made to understand the mode of inheritance of several important caladium foliar traits, including leaf shape, main vein color, leaf spotting, and leaf