WHEAT BREEDING FOR SOIL ACIDITY AND ALUMINUM TOXICITY

摘要

The soils of southern and central-southern Chile where the national wheat productionis concentrated are of volcanic origin, with low pH and with high exchangeablealuminum. Soils contain large amounts of phosphorous in organic form, howeveravailable phosphorous is low. The high content of free Al negatively affects theroot growth of wheat varieties depending on their Al-sensitivity or Al-tolerance. Themechanism of tolerance is exclusion of toxic Al as a consequence of root excretionof queelant organic acids; roots of tolerant varieties are also protected by higher rootmycorrhizal colonization. Crosses between sensitive and tolerant material and subsequent selection under low pH and high Al have produced high yielding tolerant cultivars.This paper outlines the development of tolerant wheat varieties, describes the germplasmused and discusses the selection process including including the use of growth chambers,greenhouse assays and field experiments.