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Harrison G. Hughes

The merging of the Landscape Architecture Program (LA) with the Department of Horticulture had no effect on visibility of horticulture at Colorado State University and in the state. It did enhance the stature of the merged department as it became second only to the Department of Animal Sciences in terms of undergraduate majors and graduates in the College of Agricultural Sciences. The merger had only a limited impact on the budget. The LA is accredited. Accreditation standards aided the LA in justification of a new position. Since the merger, the Landscape Design and Contracting Program has become accredited through the Associated Landscape Contractors of America (Reston, Va.). Horticulture, which has no accrediting agency, is at a disadvantage in competing for open positions.

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Hrvoje Rukavina and Harrison G. Hughes

Saltgrass (Distichlis spicata) has received increased attention as a result of its low input needs. A good understanding of the factors that influence greater flower production in saltgrass clones would facilitate seed production management and hybridization in the breeding program. Therefore, the influence of sampling time from the field, nitrogen (N) fertilization, and burning on flowering spike production of five saltgrass clones from three cold-hardiness zones were evaluated over 2 years. Clones were sampled from the field at two times (August and November) in the first and at three times (August, November, and January) in the second experimental year. After field sampling, clones were transferred to the greenhouse and received N and burning treatments. N fertilization increased number of spikes (flowering) for all saltgrass clones by ≈30% in both experimental years. In the second experimental year, the number of spikes was increased to a greater extent when N was applied in combination with burning treatment as compared with N without burning. The burning treatment had a greater effect on the number of spikes in plants sampled in August as compared with those sampled in November and January. Sampling in November increased flowering in three clones as compared with August sampling, but with the greatest effect in clone A1540. Sampling in January further increased the number of spikes in clones 1490 and A1610 but with no significant effect on the number of spikes in clone A1540. Environmental adaptation associated with origin of saltgrass clones is a major factor that influences flowering spike production.

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Aaron Brown and Harrison G. Hughes

Callus induction and regeneration of alkaligrass (Puccinellia distans) was developed in our laboratory for use in transformation studies of turfgrass. Particle bombardment of the embryogenic callus is being evaluated using a helium particle inflow gun constructed at Colorado State Univ., according to the design of Philippe et al. (Ohio State Univ., 1993). Its utility in delivering DNA to plant cells is being tested by measuring the frequency of transient gene expression of a reporter gene (GUS pBI121) in embryogenic callus of alkaligrass. Varying pressure of helium and the distance of the calli in the chamber are also being evaluated for efficiency in transformation.

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Nina D. Pokriots and Harrison G. Hughes

Limited numbers of broad-leaved evergreen species grow well in the cold, dry plains of Colorado. The roundleaf buffaloberry, Sheperdia rotundifolia Parry, is a broad-leaved evergreen species that's adaptable to xeriphytic conditions of the Western states. Since little propagation information is available for this species, we studied procedures for clonal propagation with emphasis on tissue culture procedures. In this study, we evaluated the use of liquid media overlays on rapid propagation and the influence of node position on growth. A comparison of media overlay, transfer to fresh media and a control of no transfer (remained in same media) showed limited differences among treatments. Comparison of terminal, middle and basal node sections showed considerable differences. Sections from the middle produced more branches than the terminal and basal sections, though the branches were shorter than the terminal sections.

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Kerrie B. Badertscher and Harrison G. Hughes

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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Anne E. Sama and Harrison G. Hughes

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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Hrvoje Rukavina, Harrison G. Hughes and Yaling Qian

Freezing is the major abiotic stress that limits geographic distribution of warm season turfgrasses. Prior studies have indicated variation in freezing tolerance in saltgrass clones. Therefore, this study examined freezing tolerance of 27 saltgrass clones as related to collection sites in three zones of cold hardiness. Furthermore, these clones were evaluated for time of leaf browning in the fall with the intent to determine if there was a correlation between this trait and freezing tolerance. Rhizomes were sampled during 2004 and 2005 midwinters from clones established in Fort Collins, Colo., and then subjected to a freezing test in a programmable freezer. Saltgrass freezing tolerance was highly influenced by the climatic zone of clone origin in both years of the experiment. Clones with greater freezing tolerance turned brown earlier in fall in both seasons. Ranking of zones for the average LT50 (lethal temperature at which 50% of rhizomes died) was: zone 4, most northern (−17.2 °C) < zone 5 (−14.4 °C), < zone 6, most southern (−11.1 °C) in 2004, and zone 4 (−18.3 °C), < zone 5 (−15.7 °C) < zone 6 (−13.1 °C) in 2005. Clones from northern areas tolerated lower freezing temperatures overall. This likely indicates that freezing tolerance is inherited. Large intraspecific variation in freezing tolerance may be effectively used in developing cold hardy cultivars.

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Janice L. Stephens and Harrison G. Hughes

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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Janice L. Stephens and Harrison G. Hughes

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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Harrison G. Hughes and James E. Klett

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.