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A control burn was conducted in a mixed black oak—white oak—post oak stand to determine the effectiveness of fire at removing midstory and understory trees. The midstory and understory was predominately invading species of red maple, dogwood, black cherry, black gum, and mockernut hickory with lesser amounts of canopy species—black oak, white oak, post oak, and blackjack oak. A total of 17,000 stems/ha were top killed. All stems below 10 cm (15,600 stems/ha) were killed and all of the invading species were all top killed. Large black oak (greater than 20 cm) were killed by hypoxylon which may or may not have been related to fire. Soil pH increased from 4.6 (before) to 5.7 after the burn. The litter layer was almost completely removed. The biomass of the litter layer the year after the burn was 23% of the biomass before burning. Herbaceous plants began to invade the site in the first summer.

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Bananas are one of the most important fruits, serving as a cash crop and staple food in many regions of the world. In Puerto Rico, bananas are an important agricultural industry, supplying all the fruit needed for local demand. Diseases significantly limit production, and the evaluation and adoption of improved genetic resistance in bananas might provide an avenue for long-term sustainable production. To this end, nine enhanced genotypes from international selection and breeding programs were introduced and evaluated for their response to black leaf streak (BLS) (Pseudocercospora fijiensis Morelet) and for their agronomic performance. Bananas were evaluated as part of a collaborative effort between the U.S. Department of Agriculture Agricultural Research Service (USDA-ARS) Tropical Agriculture Research Station (TARS) and Bioversity International’s International Musa Testing Program (IMTP). Improved genotypes were compared with disease-resistant and disease-susceptible reference genotypes across two cropping cycles. Field plants were grown following commercial production practices with no BLS management. Significant differences in disease reactions were observed during both cropping cycles for test and reference genotypes. Under high disease pressure, ‘FHIA-21’, ‘FHLORBAN 916’, and ‘FHLORBAN 920’ test genotypes showed higher numbers of functional leaves and lower disease severity at harvest in both cycles. Short cycling times were also observed for the two FHLORBAN genotypes. Larger bunches with a high number of fruits were produced by the ‘IBP 12’, ‘IBP 5-B’, and ‘IBP 5-61’ selections. Several of the GCTCV test genotypes were extremely susceptible to BLS, did not perform as expected, and appeared to be off-types. Several of the test genotypes performed well, although currently none possessed all needed traits for a commercial banana substitute. Regardless, several test genotypes have agronomic potential because they have been selected for disease resistance to other important pathogens (e.g., fusarium wilt) and therefore have become part of the permanent TARS collection. Future efforts will continue to focus on the IMTP collaboration and introduction of promising banana genotypes for evaluations.

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The year 2005 marked the 25th anniversary of the establishment of the U.S. Department of Agriculture (USDA) National Plant Germplasm System (NPGS), repositories devoted to clonally propagated, horticultural fruit and nut crops. During this quarter century, facilities in Hilo, Hawaii; Mayaguez, PR.; Miami, Fla.; and Riverside, Calif. were developed to preserve collections of tropical and subtropical fruit and nut crops; facilities in Brownwood, Texas; Corvallis, Ore.; Davis, Calif. and Geneva, N.Y. preserve the temperate crops. Each of these facilities now has internationally recognized, globally diverse collections of genetic resources for their assigned genera. Germplasm of unique genotypes are maintained as growing plants, evaluated for phenotypic and genotypic traits, documented in a national public germplasm database, and freely distributed as clonal propaggules to researchers and other germplasm users around the world. Seed collections represent wild populations for some crop relatives. These 8 genebanks maintain 30,000 accessions representing 1600 species of fruit and nut crops and their wild relatives. The genebanks distribute more than 15,000 accessions annually to international researchers. Although originally conceived as working collections for crop improvement, NPGS genebanks have also become invaluable in providing the raw materials for basic plant genetic research, reservoirs for rare or endangered species or vulnerable landraces, archives of historic cultivars, and field classrooms for educating the public. These collections preserve botanical treasures as well as the American horticultural heritage for now and for future generations.

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