Comparison between two screening approaches in the development of acid soil tolerant maize (Zea mays L.) populations

Author(s)

Carlos Daniel Giaveno

• Document type: Doctoral Thesis
• Press: Piracicaba.
• Institution: Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC)
• Defense date: 2000-09-05
• Advisor: Jose Branco de Miranda Filho

Abstract

The principal objective of this work was the comparison of the efficiency between two screening approaches for tolerance to acid soil at seedling stage as well as the study of the inheritance and the evaluation the feasibility for the utilization of biochemical markers to select tolerant genotypes as secondary objectives. One cycle of divergent selection was carried out, using nutrient solution and pots filled with acid soil. The populations were compared both in field and greenhouse trials. The coefficient of heritability was estimated using half-sib progenies in nutrient solution. Isozymes and hematoxylin staining were availed as possible biochemical markers. In all trials, the selected tolerant populations were better than the sensitives and the population selected in acid soil was better than the selected in nutrient solution. The estimated coefficient of heritability at individual plant and progeny mean levels were 0.75 and 0.84. These result indicate the quantitative nature of the trait with an important additive component. None of the isozyme systems show an acceptable association with tolerance. Hematoxylin staining is a useful procedure for selecting Al-tolerant seedlings and it shows a negative high correlation with root growth in nutrient solution of 0.82. (AU)