Genetic variation for improving the salt tolerance of durum wheat

Abstract

Durum wheat (AB genomes) is more salt-sensitive than bread wheat (ABD genomes), a feature that restricts its expansion into areas with sodic or saline soils. Salt tolerance in bread wheat is linked with a locus on the D genome that results in low Na+ uptake and enhanced K+/Na+ discrimination. In order to introduce salt tolerance into current durum wheats from sources other than the D genome, a search for genetic variation in salt tolerance was made across a wide range of tetraploids representing 5 Triticum turgidum sub-species (durum, carthlicum, turgidum, turanicum, polonicum). Selections were screened for low Na+ uptake and enhanced K+/Na+ discrimination. This was assessed in seedlings grown in 150 mМ NaCl with supplemental Ca2+, by measuring the Na+ and K+ accumulated in the blade of a given leaf over 10 days. Large and repeatable genetic variation was found. Low Na+ accumulation and high K+/Na+ discrimination of similar magnitude to that of bread wheat was found in the sub-species durum. These selections have the potential for improving salt tolerance in durum wheat breeding programs.

Salt stress manifestation on plants, mechanism of salt tolerance and potassium role in alleviating it: a review

“…However, the extent of growth inhibition due to salt-induced osmotic stress depends on the type of plant tissue and concentration of salts present in growing medium (Munns et al, 2000). In view of the above mentioned reports it is clear that salinity causes osmotic stress to plants but the extent of the effect of this stress varies from species to species.…”

Subsoil constraints to grain production in the cropping soils of the north-eastern region of Australia: an overview

“…For example, durum wheat has a much higher level of salt uptake and much lower level of salt tolerance compared with bread wheat. Durum lacks the Na + exclusion trait (Dvorak et al 1994;Munns et al 2000a), which accounts for the better performance of bread wheat than durum wheat on salinesodic soils (Dang et al 2004c;Rathjen et al 1999), whereas barley can tolerate high Na + levels compared with both bread and durum wheat (Dang et al 2004c;Munns et al 2000b). Subsoil constraints restrict rooting depth, preventing water uptake by plants.…”

Subsoil constraints in Vertosols: crop water use, nutrient concentration, and grain yields of bread wheat, durum wheat, barley, chickpea, and canola

“…Durum wheat was found to be more salt sensitive than the other 2 cereals. The sensitivity of durum wheat to salts is due to it lacking the genes for restricting Na uptake in the shoot as in bread wheat, and sequestering Na in vacuoles as in barley (Munns et al 2000).…”