Location: Tropical Crops and Germplasm Research2011 Annual Report
1a. Objectives (from AD-416)
Objective 1: Increase seed and conduct phytosanitary assessments for more than 1,000 NPGS Sorghum and Zea accessions which are subject to quarantine restrictions, so as to make additional certified, pathogen-tested seeds available to users. Objective 2: Regenerate about 8,000 NPGS accessions with few seeds, low viabilities, and adaptations to equatorial latitudes and long-seasons, emphasizing Sorghum, Zea, Vigna, Cucurbita, Leucaena, and Psophocarpus. Record key agronomic traits such as host-plant resistance to biotic and abiotic stresses.
1b. Approach (from AD-416)
Select and treat seed for freedom of signs and symptoms of pathogens; conduct annual disease surveys; inspect and verify status of plants (PPQ); grow quarantined and/or photoperiod-sensitive crops, report new diseases, maintain low pest levels, bag heads prior to anthesis; identify diseases and take regulatory action; record key descriptor information for entry into GRIN; harvest seed and examine for disease symptoms; and return seed to National Plant Germplasm System.
3. Progress Report
Research in this project is service oriented and assists ARS curators with the introduction of new germplasm, seed regeneration and increase, and recording of descriptor notes for entry into the Germplasm Resources Information Network (GRIN). Accessions of sorghum, corn, cowpea, Leucaena, cucurbits, Crotalaria and winged bean are being regenerated at St. Croix, U.S. Virgin Islands (USVI) and Isabela, Puerto Rico and descriptor notes for phenotypic traits are being recorded. A high-yielding cowpea accession with tolerance to cucumber mosaic virus (CMV) and blackeye cowpea mosaic virus (BlCMV) was identified. Four plant introductions (PIs) and one commercial cultivar some of which have shown some tolerance to alkaline soils in unreplicated, seed regeneration plots of the U.S. cowpea collection were evaluated in replicated field experiments at St. Croix, USVI and Miami, FL. PI’s 582605 and 582674 had significantly higher yield at both locations as compared to other genotypes used in the study. These genotypes may serve as an alternative to small holders in areas where agricultural production is restricted by high soil alkalinity.
1. Seed regeneration and phenotypic characterization of grain crops germplasm for the National Plant Germplasm System (NPGS). Seed of crops must be maintained alive and sufficiently diverse for scientists to be able to develop new plant varieties that can resist pests, diseases and environmental stresses. During Fiscal Year 2011, 1,663 accessions of sorghum, 36 of photoperiod-sensitive corn, 52 of cowpea, 13 cucurbits, 17 winged bean, 4 Crotalaria, and 20 Leucaena were planted and seed-regenerated by ARS researchers at St. Croix, U.S.Virgin Islands and Isabela, Puerto Rico, for seed increase and characterization of plant traits. Release of these materials to regional plant introduction stations allowed an expansion of genebanks, maintenance of viable seed, and documentation of important plant traits that are used by scientists working on the improvement of these crops. A total of 74 phenotypic descriptors were recorded for the above crops and sent to curators for incorporation into the Germplasm Resources Information Network (GRIN). Over 1000 sorghum panicles from accessions regenerated at St. Croix were photographed, images edited and database tables prepared for the Plant Genetic Resources Conservation Unit, Griffin, GA, for their incorporation into GRIN.