Inheritance and chromosome location of Alp, a gene controlling aluminum tolerance in 'Dayton' barley

Abstract

Aluminum (Al) toxicity is a major limiting factor in acid soils and more adequate genetic tolerance is needed to improve barley adaptation and production in affected regions. To study the inheritance and chromosome location of the Alp gene controlling Al tolerance in 'Dayton' barley the primary trisomics of sensitive 'Shin Ebisu 16' were crossed to 'Dayton'. Parental, F1 and F2 seedlings were grown in nutrient solution containing 0.03, 0.06 and 0.09 mM Al, and classified for tolerance by haematoxylin staining of the roots. In diploid F2 progeny, Alp was inherited as a single gene, dominant at 0.06 mM and recessive at 0.09mM concentrations, as indicated by the 3:1 and 1:3 (tolerant: sensitive) segregation ratios, respectively. Segregation of the trisomic F1-derived F2 seedlings at 0.06 mM Al deviated significantly from the 3:1 only for the triplo 4/'Dayton' cross. Data for this cross fit the expected trisomic ratios, indicating that the Alp gene is distally located from the centromere on chromosome 4. These results confirm that tolerance is simply inherited, but expression of tolerance is dependent on Al concentration and allele dose.