Hordeum marinum-wheat amphiploids maintain higher leaf K+:Na+ and suffer less leaf injury than wheat parents in saline conditions

Abstract

Wheat is only moderately tolerant of salinity and is sensitive to waterlogging. Salt and waterlogging tolerance in wheat might be improved by wide hybridization with more stress tolerant wild relatives in the Triticeae. Wide hybridization between the waterlogging-tolerant halophyte Hordeum marinum and nine wheat cultivars (Triticum spp.) produced amphiploids containing all chromosomes from H. marinum and the wheat parent. The amphiploids had lower Na+, higher K+, and a much higher K+:Na+ ratio in leaves than the respective wheat parent, and several also had less leaf injury, when grown in saline conditions. Growth responses of two amphiploids (one with a bread wheat cv. Westonia and one with a durum wheat cv. Tamaroi) were studied in a range of salinity and waterlogging treatments over 25 d. Growth of the H90-Tamaroi amphiploid was greater than Tamaroi at 100–300 mM NaCl, whereas the H90-Westonia amphiploid was not different from Westonia, although both amphiploids had higher leaf K+:Na+ ratios. Under a combination of waterlogging and salinity, both amphiploids were superior to the wheat parents. This study demonstrates the potential of genes from H. marinum to improve the salt and waterlogging tolerance of wheat.