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Shawn A. Mehlenbacher and Maxine M. Thompson

The style color of standard hazelnut (Corylus avellana L.) cultivars ranges from pink to dark purple. Styles with an unusual yellow color were first noted in seedlings of the progeny `Goodpasture' × `Compton', and the ratio was ≈3 red: 1 yellow. Controlled crosses were made to investigate the genetic control of style color. The same 3:1 ratio was observed in four additional crosses in which both parents had red styles. Two crosses of a red and a yellow parent gave ≈50% yellow styles, while a cross of two selections with yellow styles gave only seedlings with yellow styles. These segregation ratios indicate control by a single locus, with yellow style color recessive to red. Seedlings with yellow styles have green buds and catkins and a more upright growth habit than their siblings with red styles. Inspection of the pedigrees of these progenies shows that `Daviana', `Willamette', `Butler', `Compton', `Goodpasture', and `Lansing #1' are heterozygous. `Daviana' appears to be the original source of the allele for yellow styles, as it is a known or suspected parent or ancestor of the others. Ratios in a progeny segregating simultaneously for growth habit (normal vs. contorted) and style color indicated independence of the traits. However, in a progeny segregating simultaneously for leaf color (red vs. green) and style color, no redleaf seedlings had yellow styles. The S-alleles of eight genotypes with yellow styles were determined, and indicate a possible linkage between the yellow style locus and the S locus that controls pollen-stigma incompatibility. One explanation is that the yellow style trait is conferred by an allele (a ys) at the anthocyanin (A) locus that controls leaf color. A second explanation is that there is a yellow style locus closely linked to the A locus. The A locus is known to be loosely linked to the S locus.

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Jeffery K. Iles

M aples F or G ardens , A C olor E ncyclopedia . C.J. van Gelderen and D.M. van Gelderen. 1999. Timber Press, Inc., 133 S.W. Second Avenue, Suite 450, Portland, OR 97204-3527. 294 p. 683 color photos. 2 color maps. $49.95, hardcover

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Walter Boswell, Bernard Bible, and Suman Singha

Flesh color has been proposed as a maturity index for peaches. The objective of the present study was to determine the effectiveness of this parameter in `Loring', `Jersey Dawn', `Madison', and `Raritan Rose' peach (Prunus persica L. Batsch). Fruit were picked at weekly intervals at three or four harvest dates, with five fruit per cultivar being picked from each of three trees. Flesh firmness and soluble solids were measured immediately following harvest, and CIELAB coordinates (L*a*b*) of blush and flesh color were determined with a Minolta CR-200b calorimeter. There was a highly significant correlation (P < 0.001) between firmness and flesh hue angle for all four cultivars and with flesh chroma especially for the white-fleshed `Raritan Rose'. The correlation values between firmness and blush hue angle were consistently lower. Soluble solids did not consistently correlate with flesh or blush color. Even though blush color influences consumer preference, it was not as good an indicator of maturity as flesh color for the cultivars that we tested.

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Elzette van Rooyen* and Randolph Beaudry

The objective of this study was to evaluate preharvest fertilizer application and postharvest storage temperature and duration as they affect the intensity and stability of color in red and purple potato cultivars during storage. `Michigan Purple', `Dakota Rose', and `Chieftain' were stored at 4 °C and hue angle (h°) was measured weekly. The initial `Michigan Purple' h° of 1.1° changed to 23.2° after 18 weeks of storage (a shift in h° from 350° to 30° changes from purple to red) while the initial hue angle of 18.5° and 34.1° for red-skinned cultivars, `Dakota Rose' and `Chieftain', changed to 27.2° and 43.2°, respectively. Hence, the degree of color shift was greater in `Michigan Purple' although all the cultivars in this experiment underwent significant color change during storage. Hue angle of `Michigan Purple' tubers stored at 4°, 10°, and 20 °C for 8 weeks changed 19.4°, 12°, and 14.2° toward the redder h°, respectively. Thus, the color of `Michigan Purple' tubers changed the least at 10°C. Hue angle of `Michigan Purple' tubers fertilized with 180 lbs/acre slow-releasing nitrogen, 180 lbs/acre nitrogen, 270 lbs/acre nitrogen, and 2.5 lbs/acre poultry manure was measured after 5 weeks at 4 °C. Hue angles were 0.92°, 11.65°, 3.99°, and 1.34°, respectively. The hue of the first three treatments differed significantly from one another, but the hue of the potatoes treated with 180 lbs/acre slow-releasing nitrogen and 2.5 lbs/acre poultry manure did not differ. Preharvest factors like plant nutrition can influence tuber color in storage and `Michigan Purple' tuber color is particularly sensitive to storage temperature.

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Mengyang Liu, Yin Lu, Shan Wang, Fang Wu, Jingrui Li, Yanhua Wang, Jianjun Zhao, and Shuxing Shen

Leaf color is largely the result of photosynthetic pigments, primarily chlorophyll (Chl). Chl plays an essential role in light absorption for energy transfer ( Stern et al., 2004 ). The Chl biosynthesis pathway is complex and involves more than 20

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R.D. Berghage and D.J. Wolnick

Potential consumers were surveyed in the spring of 1996 to gain insight into preferences for flower and leaf color in New Guinea impatiens (Impatiens hawkeri Bull.). Survey participants indicated a preference for bright solid colors, and bicolor flowers. The most preferred solid flower colors were red-violet, and red. The least preferred solid flower colors were pink and blush. Potential consumers ranked bicolor flowers over their solid color counterparts. Red and variegated foliage were preferred to solid green. Foliage with solid red upper or lower surfaces were preferred 2:1 over variegated foliage.

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Zongyu Li, R. Karina Gallardo, Vicki A. McCracken, Chengyan Yue, Ksenija Gasic, Gregory Reighard, and James R. McFerson

disease, caused by the fungus Monilinia fructicola , which causes significant losses to the southeastern U.S. peach crop ( Schnabel et al., 2010 ) and the fruit quality attributes of size and fruit color (blush). Although the development of resistance to

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Anusuya Rangarajan and Betsy Ingall

Interest in the production of the specialty vegetable radicchio (Cichorium intybus L. var. silvestre Bisch.) has increased among vegetable growers in the northeastern United States due to the popularity and consumption of premixed prepared salads. Growing environments with moderate daytime temperature and high light level have been associated with dense, deep red heads. Production problems include the low percentage of plants producing marketable heads and labor costs associated with hand-weeding. Traditional bareground culture was compared with several colored mulches (white, silver, red, black, and blue) for their effects on head formation, size, yield, and color of two Italian cultivars. Field studies were conducted in Freeville (upstate), N.Y., in 1997 and 1998. The percentage of heads harvested ranged from 32% to 82% over the 2 years of experiments and was lowest in black and red plastic mulch treatments. Yields were significantly higher, heads larger, and harvest earlier for plants grown over silver and white mulch compared to the control and other mulch treatments in 1998. In addition, average head weight was greater in all mulch treatments except blue when compared with the control. Cultivar differences were measured for the number and weight of heads, the percent bolting and marketable heads, and head color in 1998. Air and soil temperatures varied significantly around these mulches; however, these differences in microclimate had no effect on head color quality. Despite relatively moderate temperatures in upstate New York, radicchio responded positively to mulches that lowered average soil temperatures (white and silver) compared with the other treatments.

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W.C. Lin, J.W. Hall, and A. Klieber

A video-imaging technique, using commercial software to process images obtained at 550 nm, was established to estimate chlorophyll content of cucumber fruit disks. The chlorophyll content of excised disks was extracted, determined, and regressed on the video-image grey level. They were linearly related. The change in grey level of the whole visible image accurately indicated the change of green color during fruit development on the vine and the loss of green color after 1 week of storage at 13C. The relationship of the chlorophyll content on grey level was quadratic for three imaging methods: 1) average grey level of the five disks; 2) average grey level of the whole cucumber image; and 3) average grey level of central one-third of the whole cucumber image. Chlorophyll content was most highly correlated to the grey level of the disks themselves (residual SD = 6.74 μg·cm-2), but this sampling technique was destructive. Both one-third of the fruit image (SD = 9.25 μg·cm-2) and the whole image (SD = 9.36 μg·cm-2) provided satisfactory precision. For simplicity, whole-fruit imaging is suitable for estimating fruit chlorophyll content and for quantifying fruit green color intensity. Potential use of this technique in product sorting and shelf life prediction of long English cucumbers is discussed.

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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