GENETIC EXPRESSION OF ALUMINUM TOLERANCE IN HARD RED WINTER-WHEAT

Genetic variation for aluminum (Al) tolerance in hard red winter (HRW) wheat has been reported. Our objectives were to characterize the genetic control of Al tolerance in HRW wheat relative to the tolerant soft red winter (SRW) wheat cultivar, Atlas 66. Hybrid progenies generated from factorial and diallel matings were evaluated in nutrient-solution culture containing 0 (control), 0.36, and 0.72 mM Al. Degree of hematoxylin staining and relative length (% of control) of seedling roots were used as indicators of Al tolerance. The HRW cultivars, Dodge, Wrangler, and HR64, were previously classified as tolerant, but they differed from Atlas 66 in the magnitude of general effects on F1 performance. Degree of tolerance of F1's derived from a common tolerant parent was highly influenced by the susceptible parent genotype. Inconsistent dominance relationships among hybrid progenies confirmed that Al tolerance in HRW wheat is under complex genetic control. Atlas 66 may possess genes for Al tolerance not present in HRW wheat, since it proved to be more tolerant than any of the HRW wheat genotypes.