Genome Structure and Salt Stress Response of Some Segregated Lines from Wheat and Tritipyrum Crosses

Abstract

We evaluated the genome structure and salt stress response of BC₁F₆ lines derived from a cross between an Iranian salt tolerant bread wheat cultivar ‘Roushan’ (2n=6x=42, AABBDD) and a synthetic allohexaploid Tritipyrum (2n=6x=42, AABBE^bE^b). Sixteen lines (L1 to L16) and their parents were studied for their chromosome composition, K⁺ : Na⁺ ratio, and relative dry mass (RDM) by growing them in nutrient solution containing 0 (control) or 100 mM NaCl (treatment). Among the studied lines, eight wheat—Thinopyrum bessarabicum (E^b genome) disomic substitution lines were identified using PCR-based Landmark Unique Gene (PLUG) markers and cytogenetic analysis. Ten (37%) of 27 PLUG markers used were informative for E^b chromosomes 1, 2, 3, 4, and 6 in a wheat background. PLUG markers also revealed that one line, L9, was a disomic substitution line DS2E^b(2B), and that seven lines, L3, L4, L7, L8, L14, L15, and L16, were DS6E^b(6D). There were large differences in morphological traits and salinity tolerance even among DS6E^b(6D) substitutions or untranslocated lines, due perhaps to unidentified rearrangements or small introgressions.