Aluminum tolerance in barley: Methods for screening and genetic analysis

Aluminum (Al) tolerance in roots of two cultivars of barley was studied using hematoxylin staining and root re-growth procedures. This study was performed in two F^sub 2^ segregating populations originated from crosses between the tolerant FM-404 and sensitive Harrington cultivars. The F^sub 2^ progeny analysed with hematoxylin staining revealed a segregation ratio of 3 tolerant: 1 sensitive, showing that the Al tolerance is controlled by a single gene with complete dominance for tolerance. The root re-growth measures do not confirm the 3:1 ratio. This last result can be explained due to the occurrence of genes that affect root growth rate or to the difficulties found in the evaluation of root re-growth. Barley has a complex root system, which makes it difficult to measure root re-growth after an extended period in nutrient solution. Due to the simplicity, reliability and better precision, the hematoxylin staining is the best procedure to determine the Al tolerance and its inheritance in barley.[PUBLICATION ABSTRACT]