Search Results

You are looking at 91 - 100 of 4,880 items for :

  • Refine by Access: All x
Clear All
Free access

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

Full access

Renata Koyama, Ronan Carlos Colombo, Wellington Fernando Silva Borges, João Pedro Silvestre, Ibrar Hussain, Muhammad Shahab, Saeed Ahmed, Sandra Helena Prudencio, Reginaldo Teodoro de Souza, and Sergio Ruffo Roberto

’)] × ‘BRS Linda’. This new hybrid seedless grape is tolerant to downy mildew, the main grape disease in subtropical humid areas, requiring fewer fungicide applications. However, their slightly pinkish clusters show color deficiency when cultivated in warm

Full access

Meredith R. Blumthal, L. Art Spomer, Daniel F. Warnock, and Raymond A. Cloyd

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.

Open access

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

Free access

Xuetong Fan and James P. Mattheis

Climacteric `Fuji' apples (Malus ×domestica Borkh.) were treated with water, 0.45 mmol·m–3 1-methylcyclopropene (MCP), 2 mmol·L–1 methyl jasmonate (MJ), or both MCP and MJ. Fruit were kept at 20 °C for 17 days after treatment. Ethylene production, respiration, and color change were all inhibited following MCP treatment. Ethylene production following MJ treatment fluctuated below and above that of controls, but was representative of postclimacteric apples at all times. Rates of respiration and color change were enhanced by MJ, even when fruit were previously treated with MCP. The results indicate that MJ can enhance rate of color change and respiration in apple fruit independently of ethylene action.

Free access

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

Free access

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.

Free access

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.

Free access

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

Free access

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