Quantitative Trait Loci for Component Physiological Traits Determining Salt Tolerance in Rice1
Rice ( Oryza sativa ) is sensitive to salinity, which affects one-fifth of irrigated land worldwide. Reducing sodium and chloride uptake into rice while maintaining potassium uptake are characteristics that would aid growth under saline conditions. We describe genetic determinants of the net quantit...
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Veröffentlicht in: | Plant physiology (Bethesda) 2001-01, Vol.125 (1), p.406-422 |
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Sprache: | eng |
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Zusammenfassung: | Rice (
Oryza sativa
) is sensitive to salinity, which
affects one-fifth of irrigated land worldwide. Reducing sodium and
chloride uptake into rice while maintaining potassium uptake are
characteristics that would aid growth under saline conditions. We
describe genetic determinants of the net quantity of ions transported
to the shoot, clearly distinguishing between quantitative trait loci
(QTL) for the quantity of ions in a shoot and for those that affect the
concentration of an ion in the shoot. The latter coincide with QTL for
vegetative growth (vigor) and their interpretation is therefore
ambiguous. We distinguished those QTL that are independent of vigor and
thus directly indicate quantitative variation in the underlying
mechanisms of ion uptake. These QTL independently govern sodium uptake,
potassium uptake, and sodium:potassium selectivity. The QTL for sodium
and potassium uptake are on different linkage groups (chromosomes).
This is consistent with the independent inheritance of sodium and
potassium uptake in the mapping population and with the mechanistically
different uptake pathways for sodium and potassium in rice under saline
conditions (apoplastic leakage and membrane transport, respectively).
We report the chromosomal location of ion transport and selectivity
traits that are compatible with agronomic needs and we indicate markers
to assist selection in a breeding program. Based upon knowledge of the
underlying mechanisms of ion uptake in rice, we argue that QTL for
sodium transport are likely to act through the control of root
development, whereas QTL for potassium uptake are likely to act through
the structure or regulation of membrane-sited transport
components. |
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ISSN: | 0032-0889 1532-2548 |