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RESEARCH ARTICLE

Genetic control of sodium exclusion in durum wheat

Rana Munns, Gregory J. Rebetzke, Shazia Husain, Richard A. James and Ray A. Hare

Australian Journal of Agricultural Research 54(7) 627 - 635
Published: 23 July 2003

Abstract

Salt tolerance in the genus Triticum is associated with low accumulation of Na+ in leaves. Durum and other tetraploid wheats generally have high accumulation of Na+ relative to bread wheat, and are salt sensitive, but a durum wheat landrace, Line 149, was found to have unusually low leaf Na+ accumulation. Populations were developed from crosses between 149 and the high Na+ accumulation variety Tamaroi, as well as between 149 and a durum wheat landrace with very high Na+ accumulation, Line 141. The third leaf of parental lines, F1, F2, and low- and high-selected F2:3 progeny was assayed for Na+ uptake when grown in 150 mM NaCl. Sodium concentrations were significantly (P < 0.01) lower in the low Na+ uptake Line 149 compared with high Na+ uptake Tamaroi (5-fold greater Na+ accumulation) and Line 141 (7-fold greater Na+ accumulation). There was no evidence of any maternal genetic effect on Na+ accumulation. The F1 progeny mean was intermediate to the mid- and low-parent means, suggesting incomplete dominance gene action. Progeny in the F2 generation of both populations segregated for Na+ accumulation in a 15 (low Na+) : 1 (high Na+) ratio (χ215:1 = 0.27 and 0.46, P > 0.50n.s. for 149/Tamaroi and 149/141, respectively), indicating duplicate dominance epistasis arising from segregation of 2 interacting dominant genes. Small yet significant (P < 0.01) genotypic variation was also observed for minor genes affecting Na+ accumulation. Realised heritabilities were moderate to high (h2R = 0.43–0.90) across populations, indicating good response to selection for low Na+ accumulation in the F2 generation. The simple genetic control of Na+ accumulation suggests relative ease of selection of lines with low Na+ accumulation. However, presence of dominance will require selection to be delayed until after 1 or 2 generations of inbreeding, or after progeny-testing of selected low Na+ accumulation families.

https://doi.org/10.1071/AR03027

© CSIRO 2003

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