germination of different jujube cultivars collected in New Mexico. The two unique germplasm resources of ‘Zaocuiwang’ and ‘Yu’ were identified during the phenology observation and pollen study process. Materials and Methods This experiment was conducted at New
USDA's National Plant Germplasm System (NPGS) maintains the world's largest living collection of plant genetic resources. The NPGS is tasked with acquiring, preserving, characterizing, and distributing the over 450,000 accessions. Major components
Abstract
A critically important aspect of the management of genetic resources is concurrent management of information pertinent to the preserved seeds or plant materials. An effective information system should: a) aid curators of collections by providing current information on inventories, exchange activities, etc.; b) perm it germplasm users to have rapid access to botanical and horticultural information about specific accessions and thereby encourage more effective use of plant germplasm; and c) allow personnel and organizations within and between countries to coordinate activities related to germplasm collection, exchange, and maintenance.
, China has rich plum germplasm resources. According to Zhang (1990) , there are eight species, five botanical varieties, and ≈800 local cultivars distributed from Yi'an in Heilongjiang Province (lat. 47°50′N) to the middle parts of the Leizhou Peninsula
New potential citrus germplasm accessions may be received as seed rather than budwood, thereby reducing phytosanitary risks. However, trueness-to-type may be an issue with seed materials because many varieties produce both apomictic (nucellar) and sexual (zygotic) embryos and most citrus is fairly heterozygous. To identify nucellar seedlings of polyembryonic types and to retain these as representing the type, we screened 1340 seedlings from 88 seed sources for markers amplified with two inter-simple sequence repeat (ISSR) primers. Sixteen seed sources produced no seedlings classified as being of nucellar origin. Among the remaining seed sources, seedlings classed as nucellar were identified for potential addition to the collection. In 37 accessions, both nucellar and zygotic seedlings were detected, and in some cases both types were retained. Inclusion of established accessions of the same cultivar group in the analysis allowed an initial assessment of similarity to existing accessions. This technique improved the efficiency of acquiring new germplasm of polyembryonic types by seed. The method identifies those seed sources that produce few or no nucellar seedlings, but it is not useful for determining which seedlings of monoembryonic types should be retained in collections.
sunny and dry mountain slopes. A national collection of P. orientalis germplasm resources has been preliminarily established, and these germplasm resources provide data for the genetic improvement and innovative utilization of P. orientalis . The
helpful comments of Michael Dosmann. I would like to acknowledge Allan Stoner and Ned Garvey of the USDA-ARS National Germplasm Resources Laboratory for their support of the Plant Exploration Program. I would like to thank Judi duCellier for producing the