Hydrogen and aluminium tolerance

Summary Reduced productivity due to soil acidity has been demonstrated with subterranean clover and wheat in many parts of Australia. Nodulation in clover appears to be more sensitive to low pH than growth of the host plant in the presence of adequate mineral nitrogen. Low pH is associated with aluminium toxicity in a number of species and nodulation in clover is more sensitive than growth of the host plant to Al. Decrease in soil pH is associated with significant increases in exchangeable Al. The breeding of Al tolerant wheats in Australia involves a backcross programme utilizing the transfer of tolerance from the Brazilian cultivar Carazinho.