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- Author or Editor: W. H. Gabelman x
Abstract
From the earlier papers in this symposium it should be apparent that horticulturists have 2 basic concerns with pollution; namely, how do pollutants effect the growth of the plant and how do pollutants effect the animals that utilize the plant. We are interested in exclusion of the pollutant from the metabolic areas of the plant and tolerance to the pollutants when in the metabolic areas or both. The response of plants may be lethal, sublethal, or without any apparant change. But if the effect is not lethal, the plant has built-in adaptive systems to enhance its probability for adaptation and survival. This knowledge gives mankind a tool for survival also.
Abstract
Most biologists agree that the genetic composition of the plant determines the potential response of the plant. Against this genetic background, the environment exerts its effect by enhancing or limiting the myriad of potential biochemical sequences that reside in the plant genotype.
Abstract
Plant breeding is a long-term program in which useful genetic variability in plants is brought together systematically to meet the needs of mankind. The tools of the plant breeder are genetic variability, controlled matings, selection pressure and phenotypic fixation in a form (the cultivar) useful to the ultimate user. The procedure is planned much as any engineer would plan an invention or an architect a new building.
Abstract
The value of history lies in the prediction of future events. If so, horticulturists who worry about the vexing administrative problems related to the structuring of departments might find profitable an analysis of the evolution of horticulture and related departments in the United States Land Grant Universities.
Abstract
Warren H. Gabelman was born on April 18, 1921, in Tilden, Nebraska. Following graduation from Tilden High School in 1938, he entered the University of Nebraska, where it was his good fortune to have Professor H. O. Werner as an advisor and an employer. Professor Werner conveyed the “excitement of discovery” and the importance of a strong philosophy of research, which became building blocks for the professional career that developed. Sports were also important. He was an outfielder on the varsity baseball team for 3 years. It was at the University of Nebraska that he met his wife, Alberta.
Abstract
A procedure for carotenoid analysis which has practical application to genetic and breeding research is outlined. It includes extraction, separation of total carotenoids by partition on a silica column into carotene and xanthophylls, and the separation of the carotene fraction into specific pigments using thin-layer chromatography. The relative concn of specific pigments in the carotene fraction was measured using a semi-quantitative technique: Four genetic lines of carrot and four tomato cultivars were analyzed. Wide differences between carrot lines were detected in total carotenoids and the relative concn of the various pigments. The tomato cultivars differed considerably in total carotenoids. The ratios of pigments (pigment pattern) of red tomato were almost identical to that of the red carrot cultivar, Kintoki.
Three cycles of half-sib family selection were practiced in a previously unselected table beet (Beta vulgaris L.) population to produce high pigment-high solids (HPHS) and high pigment-low solids (HPLS) populations. A selection index (total pigment concentration/percent dissolved solids) was used to improve the HPLS population and another selection index (total pigment concentration × percent dissolved solids) was used to improve the HPHS population. Rates of gain for total pigment were 22.2% per cycle in the HPHS population and 18.4% per cycle in the HPLS population. The HPHS and HPLS populations showed directional but nonsignificant changes for dissolved solids: 3.0% and - 2.6% per cycle, respectively. The rate of gain per cycle for selection index value (29.1%) was greater in the HPHS population than in the HPLS population (21.2%). Realized heritabilities were high for total pigment (0.81 and 0.82) and selection index (0.74 and 0.74) and low for dissolved solids (0.25 and 0.27) in both populations. Variation among families was greater for total pigment than for dissolved solids.
Sixty highly homozygous tomato (Lycopersicon esculentum Mill.) strains, some selected from previous studies and some collected from known low-Ca regions, were screened under a low-Ca culture system (10 mg of Ca per plant). Four strains were selected to represent the extremes for Ca efficiency and used as parents to create a series of F1, F2, and backcross generations for inheritance studies of Ca use under low-Ca stress. Based on total plant dry weight, additive and dominance gene effects were most important for the efficiency of Ca use. Maternal control of efficiency in Ca use was not observed. Estimates of broad-sense heritability ranged from 63% to 79% for total play dry weight. Narrow sense heritabilities, determined in only two of the families, were 47% to 49$ and 68% to 75%.
Abstract
Dominant monogenic control of purple petiole (G) over green (g) was found in the carrot. Variations observed in intensity of purple suggested presence of modifier genes. Plants having purple petioles were easily identified at all stages of growth following true-leaf formation.
Abstract
Changes in betacyanine (red pigment) concentration, betaxanthine (yellow pigment) concentration, and percent dissolved solids associated with growing time and season were studied in roots of 12 cultivars of table beet (Beta vulgaris L.) Differences among cultivars and cultivar × harvest date interactions were detected for each trait. Depending on cultivar and planting date, betacyanine concentration increased, decreased, or remained constant with increased growing time, while betaxanthine concentration and percent dissolved solids invariably increased over the same period. Beets planted on July 12, 1978, had greater pigment concentrations than beets planted on June 9, 1978, when grown the same number of days. At 83 days after planting, root weight was negatively correlated with betacyanine concentration (r = −0.44) and betaxanthine concentration (r = −0.40), but after 136 days, both correlations were reduced in magnitude (r = −0.23).