Screening wheat and other small grains for acid soil tolerance: Fid-Bau Portal

Screening wheat and other small grains for acid soil tolerance

Bona, L. / Wright, R.J. / Baligar, V.C. / Matuz, J.

AbstractAluminum (Al) toxicity in acid soils is a major growth-limiting factor for cereal crops in many parts of the world. The most striking effect of high Al concentration in acid soils is stunting of the root system. Liming reduces Al toxicity in surface soils; however, cereal breeders must be prepared to develop cultivars that have tolerance to soil acidity. A 4 day root bioassay, originally used to identify Al toxics soils, was adapted to evaluate tolerance to soil acidity of cereal species and genotypes. Acid soil tolerance was related to the extent of inhibition of root elongation in an Al-toxic soil (pH 4.2) relative to root elongation in the same soil treated with lime (pH5.2). Of the entries, 18% were tolerant or moderately tolerant, and 48% were susceptible or moderately susceptible when 75 bread wheat (Triticum aestivum L.) genotypes were tested. None of the 22 entries of durum wheat (Triticum durum Desf.) were tolerant or moderately tolerant, indicating much lower adaptability to soil acidity than bread wheat. The following ranking of acid soil tolerance of cereal species was obtained: rye (Secale cereale L.) #62;oats (Avena sativa L.) #62;millet(Panicum miliaceum L.) #62;bread wheat (Triticum aestivum L.) #62;barley (Hordeum vulgare L.) #62;durum wheat (Triticum durum Desf.). Variation in tolerance within the other cereal species was much lower than within bread wheat species. The root bioassay method is relatively quick, simple and inexpensive. The method can also be used to screen early-generation populations because assayed seedlings are still viable and can be transplanted for growing until harvest.