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In the Fall 2004 semester, an on-line Introductory Horticulture course was offered to both Baccalaureate (BS) and dual enrolled high school (HS) students through Texas Tech University. In this preliminary study, comparisons were made between the progress of BS and HS students. Mean exam scores, lab report grades, worksheet scores, number of hits, and final scores for all populations were normally distributed. A one-way analysis of variance indicated a significant difference between mean exam scores (F = 6.950, p < 0.01) with HS scoring higher than BS students. Lab report and worksheet scores were significantly higher for BS students (p < 0.001). BS students accessed the website more often than HS students (p <.001). Final grades for the course were not significantly different (F = 6.950, p = 0.391) indicating that HS students performed as well as BS students in this online Introductory Horticulture course.
Abstract
Highly significant differences in the leaf content of 10 mineral elements occurred between seedling progenies of 7 apple cultivars. Correlations involving all 10 elements occurred between leaf contents of element pairs. A very high correlation between the accumulation of Ca and Mg suggests a common mechanism for the uptake and translocation of these elements. The wide variations between and within progenies indicate the feasibility of selecting rootstocks highly efficient in the uptake of specific nutrients. The proper use as graft components of stocks so selected offers extensive possibilities for the manipulation of the mineral composition of the scion and, thus, the control of nutrient related disorders. Tree-to-tree differences in such disorders in orchards on seedling rootstocks may be accounted for on the basis of differential nutrient uptake.
Fruit of `Mohawk' in 1986 and 1988 and `Shoshoni' pecan [Carya illinoensis (Wangenh.) C. Koch] in 1986 were thinned during early August using a pecan shaker with modified shaker pads. Fruit removed ranged from 44% to 57% of the crop load. Fruit thinning increased nut size of `Mohawk' in both years, but did not affect nut size of `Shoshoni'. Kernel percentage of thinned `Mohawk' and `Shoshoni' trees increased, and kernel grade of `Mohawk' improved relative to unthinned trees. Return bloom of `Mohawk' was not affected either year by thinning, but return bloom on `Shoshoni' was increased by thinning. Mechanical fruit thinning appears to be a useful commercial tool until better thinning methods are available.
Abstract
During the winter of 1983-84, 2 periods of below normal temperatures caused severe damage to ‘Western’ pecan trees [Carya illinoensis (Wangenh.) C. Koch]. Leaf elemental concentrations of N, P, K, Ca, Mg, Mn, Fe, and Zn, and yield/tree, measured during 1983, were evaluated to determine their relationship to damage. The only factors significantly related to the amount of cold damage were N, P, and yield/tree. Leaf N2 and leaf P2 were inversely related, whereas yield was positively related to cold damage.
Abstract
Landscape design, landscape construction, landscape maintenance, and landscape irrigation projects require an accurate bidding/estimating procedure for effective cost controls and profit generation. Everything entering into the bid price must end up on a spreadsheet to determine the final figures, including an estimate of profit. As one of the last phases of the bidding process, the spreadsheet calculations are a constant source of potential error in figure transposition, miscalculation, or omission, which could lead to profit loss or to the nonawarding of a project in a competitive bidding situation. Powerful electronic spreadsheets are available for use on microcomputers, but few are used in the industry due to their high cost, the generic nature of the spreadsheet programs, and the unavailability of spreadsheets specifically constructed for bidding. Additionally, electronic spreadsheets generally require formatting with appropriate equations before they can be used (1).
The contorted hazel, Corylus avellana `Contorta', is an ornamental tree prized for its grotesquely twisted trunk and branches. `Contorta' was discovered in a hedgerow in England about 1863 and has been commercially propagated by layerage or graftage because it was thought to not breed true from seed. We investigated the inheritance of contorted growth habit in the course of our work breeding hazelnuts. Crosses between normal growth habit cultivars and `Contorta' produce all normal seedlings. Sib matings of compatible normal seedlings of `Contorta' produce offspring in the proportion of 3 normal: 1 contorted. The backcross of a normal `Contorta' seedling to `Contorta' gives progeny in the ratio of 1 normal: 1 contorted, indicating control of the trait by a single recessive gene.
Tyvek housewrap (Du Pont, Wilmington, Delaware), an air-infiltration barrier for use in house construction, has been put to a novel use for making pollination bags for breeding hazelnuts (Corylus avellana L.). Bagged flowers are used in making crosses and incompatiblity testing and remain receptive for up to 3 months. Tyvek has outperformed paper and plastic materials we have tried in terms of durability and cost. Tyvek is a spun-bonded, nondirectionally oriented film of highdensity polyethylene fibers that is permeable to water vapor and air, but is water resistant and pollen-proof, and can be made into bags of any size needed.
Abstract
Hazelnut kernels from which the pellicle can be removed easily by dry heat are highly desirable for the international kernel market. Cultivars vary from no to complete pellicle removal after heating. Nut samples of 951 seedlings representing 62 parental combinations were roasted at 130°C for 13.5 min, rubbed, and scored for degree of pellicle removal. Narrow sense heritability, estimated by regression of progeny means on midparent values, was 48% (±10%). This moderately high heritability estimate indicates that selection of easy-to-blanch seedlings should result in rapid progress.