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Renewed interest in red raspberry production in Colorado has been limited by winter kill of canes. Winter kill in Colorado may be the result of extreme cold temperatures, desiccation, or a combination of the two. We are evaluating winter protection strategies to increase survival and to better understand the winter stress of raspberries. The four (4) cane treatments of red raspberry, Rubus ideaus L. cv. Heritage, used were (1) canes bent and wrapped with plastic; (2) canes bent and mulched with hay and soil; (3) canes upright with anti-desiccant spray; (4) a control of canes upright without protection. Moisture content and electrolyte leakage were evaluated at intervals. Relative moisture loss was greatest in the control as compared to the other treatments. The terminal sections of the canes exhibited greater moisture loss as compared to basal sections in the control with a similar trend in the other treatments. Relative survival as indicated by electrolyte leakage was monitored and will be correlated with moisture loss.

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Research involving acclimatization of in vitro plantlets by reducing the relative humidity (RH) in vitro requires a suitable method for monitoring RH in the culture vessels. In this research we describe a method for measuring the RH dynamically in the culture vessels, based upon thermocouple psychrometry. Thermocouple junctions (.003 mm gauge) were used with a wet cotton thread on the wet bulb junction inserted from the side of the jar. Aspiration was provided by tiny fans run by miniature motors left outside the vessels. Pre-calibrated aspirated and non-aspirated experiments showed realistically reduced RH in the cultures covered with caps which allowed for gas exchange. The aspirated procedure resulted in greater precision. This procedure with some refinement could be a useful method for monitoring RH in in vitro cultures.

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Shoot tips, approximately 3-5mm, were isolated from corms of young greenhouse-grown plants of cocoyam, cultivar South Dade White. After preliminary evaluations, the initiation media evaluated were B5 basal salts supplemented with 0.05 μM NAA with 5μM BAP, 20μM BAP or 2μM TDZ. The above media were in the form of liquid medium in flasks on a rotary shaker, liquid medium with filter paper bridges, stationary liquid medium without filter paper and solidified medium with 0.4% agar. TDZ stimulated greater growth with multiple shoot formation. Liquid media either in the shaker or stationary form were more effective in terms of growth. Shoots were subsequently evaluated for multiplication with 1μM TDZ and 5μM BAP with 0.05μM NAA producing greater shoot numbers. Over 30 plants have subsequently been rooted and acclimatized under mist or humidity tent.

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Alstroemeria is an important cut flower in the U.S. due to their wide variety of colors and to their long vase life. The most commonly grown cultivars were developed in Europe and their parentage has never been fully divulged. We are attempting to determine the probable parents of many of these cultivars through karyotype analysis and giemsa banding. Although preliminary karyotype analyses are available for 10 species and 25 cultivars, detailed karyotype analyses of only A. pelegrina and A. ligtu hybrids have been completed. Detailed karyotype analyses are now complete for 7 more species of Alstroemeria as well as the related genera Leontochir and Bomarea and 23 cultivars. A comparison among species and cultivars will be presented reflecting probable parentage of the cultivars. Results of giemsa banding will also be presented to further clarify cultivar parentage and relationships. This information should facilitate the more rapid development of successful cultivars by breeders in the U.S.

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The Dept. of Horticulture and Landscape Architecture offers majors in Horticulture with four concentrations (Floriculture, Horticultural Business Management, Horticultural Food Crops, and Horticultural Science) and Landscape Horticulture with three concentrations (Landscape Design and Construction, Nursery and Landscape Management, and Turf Management). A third major in Landscape Architecture is also offered. The department maintained the concentrations in past years of low enrollment by switching courses to alternate years, dropping nonmajor courses, and through hiring part-time staff. Currently, increasing enrollments, with limited additional funding and the need for broadened general requirements, increased career guidance, and capstone courses have increased pressures on consolidation of concentrations. Faculty have refocused senior courses to create capstone courses in several concentrations, moved the senior seminar to sophomore status for career enhancement, and are currently discussing other options.

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Isozyme analysis was used to characterize and identify 24 species, hybrids, and color variants of Alstroemeria, two plants of Leontochir ovallei, and one plant of Bomarea. A single technique was developed for the extraction of seven enzyme systems (PGM, PGI, 6-PGD, EST, ME, AAT, and LAP) that exhibited a high level of polymorphism. Between 11 and 18 of the species and hybrids could be identified uniquely for each of the first six enzyme systems. The final system, LAP, was tested on only 11 species and hybrids, and nine different patterns were identified. Using only three of the seven enzyme systems, it was possible to uniquely identify all of the species and hybrids investigated.

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Abstract

Callus from salpiglossis anthers was derived from sporophytic tissue and differentiated into flowering plantlets in vitro.

Open Access

Abstract

Octoploid strawberry, Fragaria × ananassa Duch., (2n = 56), pollinated by Potentilla anserina L. (2n = 28) and P. fruticosa L. cv. Golddrop (2n = 14) gave high achene set but germination was low and seedling lethality high in both cases. Most offspring from P. anserina died by 6 weeks with 1% survival of germinating seed at 34 weeks; offspring from P. fruticosa pollination showed gradual mortality with 7% surviving at 34 weeks. Surviving offspring from P. anserina pollinations were either 28 chromosome tetrahaploids (5 plants) or 56 chromosome octoploids (4 plants). Surviving offspring from P. fruticosa pollinations included tetrahaploids (2 plants), octoploid (1 plant), or 35-chromosome pentaploid intergeneric hybrids (9 plants). Tetrahaploids are weak with small leaves and two that have flowered are pollen and pistil sterile.

Open Access

Crosses and self's were made among Fragaria × ananassa Duchn. cv. `Douglas' and `Fern' and Fragaria chiloensis (L.) Duchn. Seeds were surface sterilized, germinated and then grown on MS media (no vitamins, sucrose or hormones) with NaCl concentrations of 0 to 0.5% or 0.5% KCl. Polyethylene glycol (PEG), of corresponding water potentials, was used to induce drought stresses. Whole plant dry weights were evaluated after 50 days. Differences in salt tolerance were associated with genotype; progeny involving crosses with F. chiloensis showed greater salt tolerance. Increases in concentration of PEG caused decreased growth. The use of salt containing media may be used to evaluate strawberry seedlings for salt tolerance and, similarly, PEG may be used to evaluate for drought stress in vitro.

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In recent years there has become an increased demand for native, drought-tolerant species for private landscaping and revegetation of disturbed sites; especially in the Rocky Mountains and high plains states. Sheperdia canadensis and S. rotundifolia, native to much of this area, have already increased in popularity due to their drought tolerance and general hardiness. Micropropagation and rooting of cuttings have been investigated for these two species. S. canadensis hardwood stem cuttings were successfully rooted with 0.8% IBA at 46.5% as compared to less than 5% from previous research. S. rotundifolia produced a greater number of axillary shoots on WPM as compared to MS medium and at a moderate concentration of BA.

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