ISHS Acta Horticulturae 510: VII Eucarpia Meeting on Cucurbit Genetics and Breeding
GENETIC ASSESSMENT OF THE UNITED STATES NATIONAL CUCUMBER COLLECTION |
| Authors: | Jack E. Staub, V. Ivandic |
| Keywords: | Cucumis sativus, genetic resources, genetic diversity, isozymes, population structure, random amplified polymorphic DNA |
| Abstract:
The most important resource that mankind has, apart from innate intelligence, is germplasm. Because of the decrease in arable land and the projected increases in world population, many crops are being evaluated for their resident genetic diversity in order to formulate strategies for the effective and efficient deployment of genetic resources for plant improvement. We assessed 922 of 1345 accessions in the United States National Plant Germplasm System (NPGS) cucumber (Cucumis sativus) collection using isozymes (14–21 loci) and random amplified polymorphic DNA (71 loci) to determine the population structure of this collection. We compared this population structure with the genetic diversity in an array of 118 diverse accessions grown commercially (released or currently in use as experimental lines) since 1846. We found that the NPGS accessions are genetically diverse, that they are not in Hardy-Weinberg equilibrium, and that they differ markedly from the commercial germplasm evaluated in their genetic structure. In contrast, the commercial germplasm exhibited a remarkably narrow genetic base, and thus could benefit from the introgression of exotic genes present NPGS accessions. Backcrossing strategies combined with continued monitoring of genetic diversity via molecular marker analysis would allow for relatively rapid (3 to 5 years) development of germplasm pools leading to homogeneous, but heterozygous, highly diverse populations for plant improvement. | |
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