Articles
APPLICATIONS OF DNA MARKER TECHNOLOGY IN JAPANESE BUNCHING ONION BREEDING
Article number
770_17
Pages
153 – 158
Language
English
Abstract
Japanese bunching onion (Allium fistulosum L.) is one of the most important vegetables in East Asian countries.
F1 cultivars are becoming increasingly prevalent in Japanese bunching onion production in Japan because of the high uniformity of agronomic traits.
DNA markers are powerful tools for molecular breeding or checking genetic homogeneity of F1 hybrid seeds.
However, Japanese bunching onion is an allogamous crop, and therefore, it is considered that the parental lines of F1 hybrids should retain a certain degree of average heterozygosity and hence genetic heterogeneity.
To establish a genetic basis for the breeding of Japanese bunching onion, we isolated more than hundreds of simple sequence repeat (SSR) clones from size-fractionated genomic DNA libraries and SSR-enriched ones.
The SSR markers developed from them were highly polymorphic and applicable for the related species such as bulb onion (A. cepa Common onion group). Thirty-two SSR markers and 18 bulb onion expressed sequence tag (EST)-derived markers were located on a genetic linkage map.
In addition, SSR markers revealed a high degree of genetic heterogeneity within each cultivar, even in F1 cultivars.
Therefore, to facilitate and enhance the accuracy of cultivar identification, we proposed an SSR-tagged breeding scheme in which the plants homozygous at a few SSR loci would be selected out of a foundation seed field.
This scheme may enable to achieve efficient cultivar identification and purity determination of F1 seeds not only in Japanese bunching onion but also in any allogamous crops exhibiting severe inbreeding depression.
F1 cultivars are becoming increasingly prevalent in Japanese bunching onion production in Japan because of the high uniformity of agronomic traits.
DNA markers are powerful tools for molecular breeding or checking genetic homogeneity of F1 hybrid seeds.
However, Japanese bunching onion is an allogamous crop, and therefore, it is considered that the parental lines of F1 hybrids should retain a certain degree of average heterozygosity and hence genetic heterogeneity.
To establish a genetic basis for the breeding of Japanese bunching onion, we isolated more than hundreds of simple sequence repeat (SSR) clones from size-fractionated genomic DNA libraries and SSR-enriched ones.
The SSR markers developed from them were highly polymorphic and applicable for the related species such as bulb onion (A. cepa Common onion group). Thirty-two SSR markers and 18 bulb onion expressed sequence tag (EST)-derived markers were located on a genetic linkage map.
In addition, SSR markers revealed a high degree of genetic heterogeneity within each cultivar, even in F1 cultivars.
Therefore, to facilitate and enhance the accuracy of cultivar identification, we proposed an SSR-tagged breeding scheme in which the plants homozygous at a few SSR loci would be selected out of a foundation seed field.
This scheme may enable to achieve efficient cultivar identification and purity determination of F1 seeds not only in Japanese bunching onion but also in any allogamous crops exhibiting severe inbreeding depression.
Authors
H. Tsukazaki, T. Nunome, H. Fukuoka, H. Kanamori, I. Kono, T. Ohara, Y.S. Song, K. Yamashita, T. Wako, A. Kojima
Keywords
Allium fistulosum, linkage map, simple sequence repeat, SSR-tagged breeding
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