Reference "Molecular genetics of submergence tolerance in rice: QTL analysis of key traits"

Reference ID

7758

Title

Molecular genetics of submergence tolerance in rice: QTL analysis of key traits

Source

Ann Bot (Lond), 2003, vol. 91 Spec No, pp. 243-253

Authors (4)

Toojinda-T	Siangliw-M
Tragoonrung-S	Vanavichit-A

Abstract

Flash flooding of young rice plants is a common problem for rice farmers in
south and south-east Asia. It severely reduces grain yield and increases the
unpredictability of cropping. The inheritance and expression of traits
associated with submergence stress tolerance at the seedling stage are
physiologically and genetically complex. We exploited naturally occurring
differences between certain rice lines in their tolerance to submergence and
used quantitative trait loci (QTL) mapping to improve understanding of the
genetic and physiological basis of submergence tolerance. Three rice
populations, each derived from a single cross between two cultivars differing in
their response to submergence, were used to identify QTL associated with plant
survival and various linked traits. These included total shoot elongation under
water, the extent of stimulation of shoot elongation caused by submergence, a
visual submergence tolerance score, and leaf senescence under different field
conditions, locations and years. Several major QTL determining plant survival,
plant height, stimulation of shoot elongation, visual tolerance score and leaf
senescence each mapped to the same locus on chromosome 9. These QTL were
detected consistently in experiments across all years and in the genetic
backgrounds of all three mapping populations. Secondary QTL influencing
tolerance were also identified and located on chromosomes 1, 2, 5, 7, 10 and 11.
These QTL were specific to particular traits, environments, or genetic
backgrounds. All identified QTL contributed to increased submergence tolerance
through their effects on decreased underwater shoot elongation or increased
maintenance of chlorophyll levels, or on both. These findings establish the
foundations of a marker-assisted scheme for introducing submergence tolerance
into agriculturally desirable cultivars of rice.