Developing sodium tolerant cotton by exploiting genetic diversity within two cultivated tetraploid species

Excess sodium (Na) in the soil profile is a key limiting factor of saline and/or sodic soils which significantly affects irrigated cotton production worldwide (Gorham et al. 2010). Under saline or sodic abiotic stresses, cotton can take up and accumulate excessive levels of ions which can be toxic to the plant. Although Na can substitute for potassium (K) in cotton, when K is in a short supply, the antagonistic effect of Na can restrict plant uptake of other essential nutrients such as phosphorus (P) and K (Rochester 2010). These phenomena can lead to nutrient imbalance in plants and limit crop productivity. In cotton growing on sodic soils in Australia under high yield levels with high requirements for P and K, excessive Na uptake is regarded as one of the constraints for continued yield progress (Rochester 2010). Among the cultivated tetraploid cotton species, Gossypium barbadense is known for being better able to tolerate soil salinity or sodicity (Abul-Naas and Omran 1974). Given the importance of G. hirsutum for global cotton production, transferring these attributes through interspecific crosses has been of interest in cotton breeding (Ashraf 2002; Liu et al. 2015). We demonstrate Na and K content of mature leaves at peak flowering represented the largest discrete difference in nutrient content between G. hirsutum and G. barbadense, and leaf Na and K content also showed high genetic variability and moderate heritability within a RIL population derived from a cross between these two species. QTL mapping suggested only a few regions on different chromosomes were behind the phenotypic variation of Na, K and their ratio. Statistical analysis showed that selection would be able to reduce leaf Na and increase K content and increase leaf K/Na ratio in cotton. When backcross-derived sister lines from an interspecific cross were compared in a sodic clay soil, the lines with low leaf Na content (average 652 ppm) showed better yield than the ones with high leaf Na content (average 843 ppm). We conclude that exploiting genetic diversity of tetraploid species would lead to increased tolerance of cotton to sodic soils and would simultaneously improve nutrient status and yield. (Texte intégral)

Bibliographic Details

Main Authors:	Liu, Shiming, Constable, Greg A., Lacape, Jean-Marc, Llewellyn, Danny
Format:	conference_item biblioteca
Language:	eng
Published:	ICGI
Subjects:	F30 - Génétique et amélioration des plantes, H50 - Troubles divers des plantes, F60 - Physiologie et biochimie végétale,
Online Access:	http://agritrop.cirad.fr/582970/ http://agritrop.cirad.fr/582970/7/Liu%20et%20al%202016%20WCRC6.pdf
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