THE GENETICS AND MANIPULATION OF ALUMINUM TOLERANCE IN WHEAT

¹ Department of Agronomy, Taegu University, Jinryang-myun, Kyungson-gun, Kyngbuk, Korea

² Centro Nacional de Pesquisa de Trigo-Empresa Brasileria de Pesquisa Agropecuária (CNPT-EMBRAPA), Caixa Postal 569, Passo Fundo RS99001-970, Brazil

³ Agriculture and Agri-Food Canada Saskatoon Research Centre, 107 Science Place, Saskatoon, Saskatchewan, S7N-0X2 Canada

⁴ U.S. Department of Agriculture-ARS, Plant Genetics Research Unit and Plant Science Unit, University of Missouri, Columbia, Missouri 65211 USA.

Acid soils containing high levels of aluminum (Al) are known to severely limit plant growth on over 1.6 billion hectares worldwide. In the United States, a gradual decline in the pH of many soils both in the Great Plains as well as the Southeast, has resulted in increasingly acid soil conditions. This condition has encouraged the analysis of wheat (Triticum aestivum L.), triticale (X Triticosecale Wittmack), and rye (Secale cereale L.) germplasm from one of the major acid soil regions of the world (Brazil) in order to evaluate the genetic potential of increasing Al tolerance in cereals. The objectives were to compare Al-tolerance levels in wheats, triticales, and ryes by measuring root elongation responses in Al-containing hydroponic nutrient solutions. Rye had the longest root regrowth and Al-sensitive wheats had the shortest root regrowth. The triticales developed in the mid-1970s had the poorest root regrowth of all triticale types. The newly developed advanced triticale lines (AABBRR) yet to be released for commercial production had the highest degree of Al tolerance of any wheat or triticale and approach the levels observed in rye. This indicated that progress is being made in improving triticale's Al-tolerance in Brazil and as well as improving yield potential. Of all wheat varieties evaluated, none of them showed a higher degree of Al-tolerance, than "BH 1146" a variety that is at least 50 years old. This indicated that over the past 50 years Brazilian wheat breeders have made major yield improvements in wheat production, but not in Al-tolerance. Rye clearly showed a higher degree of Al-tolerance than any other cereal tested. The implications of these results in relation to wheat improvement and the potential expression of rye genes in a wheat background are discussed.