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- Author or Editor: J. F. Thompson x
- Journal of the American Society for Horticultural Science x
Heritability estimates for pecan [Carya illinoinensis (Wangenh.) K. Koch] nut weight, nut buoyancy, nut volume, nut density, kernel weight, and percentage kernel were determined from 8748 nut samples representing 152 families collected during 25 years in the U.S. Dept. of Agriculture (USDA) pecan breeding program at Brownwood, Texas. Measurements were corrected for year-to-year environmental variability using least-squares constants of individual year effects. Adjusted values were then regressed on midparent means. Generally, heritability (h2) estimates were low to moderate: nut weight 0.35, nut buoyancy 0.18, nut volume 0.35, nut density 0.03, kernel weight 0.38, and percentage kernel 0.32. The low values are probably due to the extreme alternate bearing tendency of this species, since crop load affects pecan nut characteristics so directly. Phenotypic correlations among these traits showed that larger or heavier nuts had significantly higher kernel weight, buoyancy, and percentage kernel. Nut density increased with higher nut and kernel weight, but decreased with nut volume.
The Munsell Color System was used to define pecan [Carya illinoinensis (Wangenh.) K. Koch] kernel colors and color changes for 21 clones, 11 locations, and 4 storage methods for nuts collected over a 4-year period. Hue readings ranged from 10.0 (10 red) to 22.5 (2.5 yellow). Value readings ranged from 2.5 to 8.0, and chroma readings ranged from 1.0 to 8.0. A total of 91 color chips (individual combinations of hue, value, and chroma) were needed to describe kernel color variability. In 1987 and 1988, one color [15.0/5/4 (hue/value/chroma)] accounted for 3,979 of the 32,078 readings taken, and the 15 most common colors accounted for 80.7% of all the readings. The Munsell system of color determination was well suited for pecan color determinations. A simplified color rating system with only six color classes was developed for general use by the pecan industry. This system is also routinely used in our breeding and genetics program to define this very important quality trait in pecan.
Abstract
Sleeved poinsettia plants (Euphorbia pulcherrima, Willd. cvs. Annette Hegg Supreme and Annette Hegg Dark Red) stored best at 10°C. Lower temperatures (2-7°C) induced chilling damages as manifested mainly by bract blueing. Higher temperatures (up to 16°) resulted in increased leaf petiole epinasty and bract drooping. The bract blueing and leaf petiole epinasty disorders became worse as storage duration increased from 2 to 10 days, while bract drooping decreased during this same period. Plants sleeved and stored in paper were generally of higher quality upon removal than those sleeved and stored in plastic. Under relatively static conditions (15m/minute air speed), poinsettias froze at about −4°. Sleeving poinsettias delayed low-temperature damage. The injury of sleeved poinsettias was related to temperature, air speed, and exposure time which can be estimated by: time to injury (minutes) = 3.94 × chill factor (°C) + 61.9.
The Munsell color system was used to study kernel color differences between four pecan [Carya illinoinensis (Wangenh.) K. Koch] cultivars (`Cheyenne', `Choctaw', `Western', and `Wichita') grown at four locations (Tulare, Calif., and Brownwood, Crystal City, and El Paso, Texas) during two seasons (1987 and 1988) and stored under different temperatures (20 to 24 °C and -5 °C). Kernel color changed over time from yellow to red hues and from lighter to darker values, but changed very little in chroma. Initial ratings of each color attribute by cultivar were positively correlated with patterns of change in that attribute over time. Kernels collected in 1987 were more yellow and had greater color saturation than kernels collected in 1988. `Cheyenne' kernels were the most yellow of the cultivars tested and `Wichita' kernels were the most red. `Cheyenne' kernels were lighter than those of any other cultivar. Kernels frozen 6 or 12 months were more red in hue than unfrozen kernels, but could not be distinguished on the basis of value (lightness). Kernels frozen 12 months had reduced chroma compared to those frozen 6 months or unfrozen. Shelled kernels of `Wichita' changed hue more in storage than kernels of other cultivars. Shelled kernels held at 20 to 24 °C became darker and developed red coloration quicker than unshelled pecans. Variation in hue and value accounted for the majority of color difference between cultivars. Changes in hue accounted for the majority of color change over time. Differences among cultivars in value (lightness) were consistent over time.
Abstract
Excessive temperatures recorded within flower boxes on transcontinental refrigerated trucks were avoided by using an integrated system of preshipment cooling with forced-air, standardized containers and appropriate stacking pattern. The longevity and quality of flowers shipped from California to Florida by refrigerated trucks were comparable to or better than that of air-shipped flowers. Preshipment conditioning treatments did not improve flower longevity of shipped roses, carnations or gladioli. Preconditioning chrysanthemum stems in AgNo3 solution eliminated the need to recut stems after shipment. Carnations and gladioli handled dry lasted as long as conditioned flowers. Floral preservative used on roses and carnations after shipping had a more positive affect on longevity than any other handling treatment.
Abstract
The longevity and quality of flowers experimentally shipped from California to Maryland by refrigerated trucks for 4–5 days were comparable with or better than simulated air-shipped flowers when properly handled. Flowers shipped by air are usually not refrigerated in transit. Best results with ‘White Sim’ carnations (Dianthus caryophyllus L.), ‘Albatross’ standard chrysanthemums (Chrysanthemum morifolium Ramat) and ‘Cara Mia’ roses (Rosa hybrida L.) were obtained when flowers were pretreated after harvest with a chemical solution for 16 hours, precooled prior to shipment and shipped in insulated boxes. Preshipment pulsing of carnations and chrysanthemums increased longevity and bloom diameter. Pulsing of ‘Cara Mia’ roses extended longevity and prevented “bent neck.” Chrysanthemums and roses benefited from ice in the box even with good refrigeration but carnations did not. Carnations and chrysanthemums cut at a tight bud stage suffered much less than open blooms from heat stress conditions during handling of flowers.