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  • Author or Editor: Michael S. Uchneat x
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Education of future consumers is a frequently discussed objective to improve consumer relations with the horticulture industry. We have developed a program which addresses this objective. The program provides examples of art projects that can be combined with simple horticultural experiences. We are presenting this program as a model to be used by horticultural professionals for the instruction of child care providers, or for direct presentation to children. Our intent is to create a greater awareness of horticulture. Often, child care providers plan educational experiences for young people based on disciplines that have been established by tradition and that are considered essential to childrens' educational development. For example, teachers might plan a nature lesson, a simple math lesson or an art lesson. This interdisciplinary plan helps children feel the connectedness of the world in which they live rather than seeing it as a series of unrelated events. Traditional motor skills are taught, along with an appreciation for seeds, plants, and the environment. Teachers may adapt the information presented here to a wide variety of activities. This approach can serve as an example of how interdisciplinary programs involving horticulture might be structured. It offers a timeline to teachers who desire to duplicate such a program, and presents many ideas, along with detailed information on how to conduct individual projects. Hopefully, this integration of art and horticulture inspires those who work with children to creatively consider the possibilities of interdisciplinary planning.

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Botrytis cinerea is an economically important fungal pathogen of Pelargonium species. We are currently studying this plant–pathogen interaction to identify mechanisms of host resistance. Our ultimate objective is to develop commercial Pelargonium genotypes with enhanced resistance to this pathogen. Though all stages of production may be affected by this pathogen, we are investigating foliar and floral resistance of mature plants. Through simple assays, over 200 genotypes have been evaluated for foliar resistance, and more than 100 genotypes have been evaluated for floral resistance. Resistant and susceptible control genotypes have been identified for diploid and tetraploid P. ×hortorum and P. peltatum; these genotypes are being investigated to elucidate mechanisms of resistance. The diploid ivy accession 86-23-1 and the tetraploid zonal geranium `Fox' have the greatest foliar resistance among the genotypes evaluated. The diploid P. ×hortorum `Ben Franklin' has the greatest floral resistance among the evaluated genotypes. Foliar and floral resistance appear to be inherited as separate traits. Foliar resistance is manifested as a two day delay in symptom expression when compared to susceptible genotypes. Foliar resistant accession 86-23-1 has a cuticle with 150% the mass of other Pelargonium genotypes. This difference may be responsible for the observed resistance. Cuticle mass does not appear to be important in floral resistance.

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Significant loss in yield of cucumber (Cucumis sativus L.) due to fruit rotting caused by Rhizoctonia solani (Kuhn) is frequently observed in the Southeastern United States. Chemical controls are costly and provide only partial control. Currently there are no resistant cultivars. The objective of this study was to identify potential sources of resistance and develop efficient screening methods for use in a breeding program. In the summer of 1991, 105 cucumber cultigens representing a range from resistant to susceptible were grown in Clinton, NC. Those cultigens were screened using field and detached fruit methods. Resistant cultigens chosen for further study were PI 165509, PI 197086 and PI 197088, with 2 to 4 % of the fruit surface damaged. Susceptible cultigens were PI 419108, PI 178886 and PI 432855, with 13 to 16 % of the fruit surface damaged. Five methods were then evaluated on greenhouse grown cucumber seedlings to identify an efficient screening method. The methods evaluated were a soil drench, a leaf dip using a mycelium suspension, syringe inoculation, and potato dextrose agar disks of R. solani placed on the third true leaf or against the hypocotyl at the soil line.

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Belly rot, caused by the fungal pathogen Rhizoctonia solani Kühn., is a severe disease in many regions that produce cucumber (Cucumis sativus L.). Annual crop loss to belly rot is commonly 5% to 10%, but losses as high as 80% can occur in individual fields. There are no resistant cultivars, so fungicides are used to provide partial control. Genetic resistance in an acceptable cultivar would be more desirable and economical. Studies were conducted in Summers 1991 and 1992 to screen promising germplasm for belly rot resistance using field and detached-fruit screening methods. In 1991, 105 cultigens (cultivars, breeding lines, and plant introduction accessions) were evaluated for belly rot resistance. The tests were repeated in 1992 with 63 cultigens, including the most resistant cultigens identified in 1991 and appropriate controls. Several cultigens were identified as potential sources of resistance genes. Pickling cucumbers showing resistance included PI 197085, PI 271328, and an F4 selection of PI 197087 × PI 280096. Slicing cucumbers with resistance included `Marketmore 76' and the F1 of Gy 14 × PI 197087. Belly rot resistance was not correlated with other horticultural traits measured, including fruit type, skin type, spine color, and firmness. The resistant cultigens identified should be useful for developing cucumber cultivars with enhanced resistance to Rhizoctonia solani.

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The objective of this study was to identify geranium cultivars that exhibit differential reactions to floral inoculation with Botrytis cinerea Per. ex. Fr. Sixty-two genotypes, including both cultivars and breeding lines, were evaluated from several Pelargonium species. Resistant genotypes included the diploid Pelargonium peltatum (L.) L'Herit. cultivar King of Balcon and the diploid Pelargonium ×hortorum L.H. Bail. cultivar Ben Franklin, as well as the diploid Pelargonium peltatum accession 93-1-33 developed from an accession obtained from South Africa. Susceptible genotypes included the putative tetraploid Pelargonium peltatum cultivar Simone. Floral resistance was not correlated with foliar resistance. Diploid genotypes appeared to have greater resistance than tetraploid genotypes, and P. peltatum cultivars more resistance than P. ×hortorum cultivars. In addition, the association of petal number and resistance was investigated.

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Foliar evaluations for Botrytis resistance of greenhouse grown plants were performed on 45 cultivars and control genotypes including diploid and tetraploid zonal (P. ×hortorum L.H. Bailey) and ivy (P. peltatum (L.) L'Hér. in Ait.) pelargoniums. Additional evaluations were performed on eight species within section Ciconium and on progeny of a susceptible by susceptible cross-pollination involving the cultivars Ben Franklin and Marilyn. Differential levels of resistance were observed. Among many genotypes that exhibited resistance, two genotypes had consistently high levels of Botrytis resistance over several experiments. These two genotypes were the diploid P. peltatum accession 86-23-1 and the tetraploid P. ×hortorum cultivar Fox. The diploid P. ×hortorum cultivar Ben Franklin was a reliable susceptible control in all experiments. Plants grown outdoors generally had higher levels of resistance than comparable greenhouse grown plants. Orthogonal contrasts indicated no trends in resistance when comparing diploid and tetraploid pelargoniums, or when comparing among ivy, zonal, and floribunda types. Genotypes patented or introduced since 1990 have greater susceptibility than older genotypes. Cross-pollinations among susceptible parents resulted in susceptible progeny, while self-pollinations of a resistant parent resulted in resistant progeny.

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