Genetic mapping of a major gene affecting onion bulb fructan content

McCallum, J. and Clarke, A. and Pither-Joyce, M. and et al, - (2006) Genetic mapping of a major gene affecting onion bulb fructan content. Theoretical and applied Genetics, 112 (5). pp. 958-967.

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The non-structural dry matter content of onion bulbs consists principally of fructose, glucose, sucrose and fructans. The objective of this study was to understand the genetic basis for the wide variation observed in the relative amounts of these carbohydrates. Bulb carbohydrate composition was evaluated in progeny from crosses between high dry matter storage onion varieties and sweet, low dry matter varieties. When samples were analysed on a dry weight basis, reducing sugar and fructan content exhibited high negative correlations and bimodal segregation suggestive of the action of a major gene. A polymorphic SSR marker, ACM235, was identified which exhibited strong disequilibrium with bulb fructan content in F2:3 families from the 'W202A' × 'Texas Grano 438' mapping population evaluated in two environments. This marker was mapped to chromosome 8 in the interspecific population 'Allium cepa × A. roylei'. Mapping in the 'Colossal Grano PVP' × 'Early Longkeeper P12' F2 population showed that a dominant major gene conditioning high-fructan content lay in the same genomic region. QTL analysis of total bulb fructan content in the intraspecific mapping population 'BYG15-23' × 'AC43' using a complete molecular marker map revealed only one significant QTL in the same chromosomal region. This locus, provisionally named Frc, may account for the major phenotypic differences in bulb carbohydrate content between storage and sweet onion varieties.

Item Type: Article
Additional Information: This research was funded by the New Zealand Foundation for Research, Science and Technology contracts C02X0203 and C02X0202. We acknowledge the assistance of Martyn Callaghan, Enza Zaden NZ Ltd, for technical advice, Paul McCartney and Winston Fahey for bulb and seed production and Doug Grant (Hybrid Seed Company) for population development.
Uncontrolled Keywords: Genetic mapping, onion bulb fructan
Author Affiliation: New Zealand Institute for Crop and Food Research Limited, Private Bag 4704, Christchurch, New Zealand.University & Research Centre, AJ Wageningen, The Netherlands, Yamaguchi University, 753-8515 Yamaguchi, Japan, University of Wisconsin, 1575 Linden Drive, Madison
Subjects: Crop Improvement
Divisions: Other Crops
Depositing User: Mr Arbind Seth
Date Deposited: 30 Sep 2012 13:02
Last Modified: 30 Sep 2012 13:02
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