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Laura C. Merrick

Collections of crop genetic resources have been assembled and evaluated as part of plant breeding efforts and in that capacity have served as the foundation for genetic improvement of crops. Most of these collections have been held at public sector institutions, including both federal and state agricultural experiment stations. However, recent changes have occurred in government agricultural research policies and funding structure which have lead to a decline in public sector breeding programs. Breeders retire and are not replaced or, for other reasons, programs are discontinued. The loss of the breeding programs maybe adversely affecting the status of the associated germplasm, if no means are provided for continued conservation of the collections. The results of a nationwide survey to assess the number and status of crop germplasm collections associated with public sector plant breeding programs and the relationship of those collections to the National Plant Germplasm System will be discussed. Recommendations will be made in regard to coordination of activities to ensure conservation of the germplasm held in plant breeders' collections.

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Laura C. Merrick

Cucurbita argyrosperma, formerly known as C. mixta, is a squash species native to Mexico and Central America. Cultivars of the species which have been grown in the United States include many of the cushaws and the `Silverseed Gourd. A recent biosystematic analysis-which included studies of experimental and natural hybridization, isozymatic and morphological variation, ethnobotany, and ecological and geographical distribution-has shown that the closest relative of C. argyrosperma is C. moschata. The data reveal intriguing implications for evolution of the genus as a whole, since the previous hypothesis that C. lundelliana is the progenitor of C. moschata is refuted. A wild ancestor, three cultivated varieties and a feral derivative are recognized within C. argyrosperma. Two of the three cultivated botanical varieties-vars. argyrosperma and stenosperma -have been selected in many regions almost exclusively for seed production. The relatively large seeds are marketed either with or without hulls. The other botanical variety, var. callicarpa, has been selected for both fruit and seed production. Northern cultivars of var. callicarpa arc notable for their adaptation to marginal environments, including hot climates and poor soil conditions.

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Laura C. Merrick

Collections of crop genetic resources have been assembled and evaluated as part of plant breeding efforts and in that capacity have served as the foundation for genetic improvement of crops. Most of these collections have been held at public sector institutions, including both federal and state agricultural experiment stations. However, recent changes have occurred in government agricultural research policies and funding structure which have lead to a decline in public sector breeding programs. Breeders retire and are not replaced or, for other reasons, programs are discontinued. The loss of the breeding programs maybe adversely affecting the status of the associated germplasm, if no means are provided for continued conservation of the collections. The results of a nationwide survey to assess the number and status of crop germplasm collections associated with public sector plant breeding programs and the relationship of those collections to the National Plant Germplasm System will be discussed. Recommendations will be made in regard to coordination of activities to ensure conservation of the germplasm held in plant breeders' collections.

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Laura C. Merrick, Frank Drummond, Constance Stubbs, and Rhonda Weber

Managed and feral honey bee (Apis mellifera) colonies have declined dramatically in the past decade due largely to parasitic mites, pesticide contamination, and severe weather. Squash (Cucurbita spp.) is one of many agricultural crops whose production may be negatively effected by decline of these pollinators. A study was conducted on a set of nine farms in Maine to assess the relationship between bee abundance and fruit set of summer and winter squash. The organic and conventional farms targeted in the study included farms with and without the presence of honey bees. With winter squash, fields with more bees tended to exhibit higher fruit set. The average fruit set was slightly higher for farms with honey bees (42%) vs. those without (35%), but both types of farms were similar to that found in controlled hand pollinations (31% on average). In contrast, fruit set for summer squash averaged 95% to 96% for all farms, regardless of the relative abundance of censused bees. Bumble bees (Bombus spp.) were the most abundant wild bees found pollinating squash. Farms with honey bees on average had higher numbers of bees in squash flowers than farms without honey bees, although a difference in preference for floral sex type was detected for bee taxa. Honey bees were much more likely to be found in female flowers, while bumble bees were more abundant in male flowers. Significantly more native bees were found in squash flowers on farms without honey bee hives, although native bees were still present to some extent on farms that were dominated by Apis mellifera.