Breeding Maize for Tolerance to Acidic Soils: A Review

Abstract

Acidic soils hamper maize (Zea mays L.) production, causing yield losses of up to 69%. Low pH acidic soils can lead to aluminum (Al), manganese (Mn), or iron (Fe) toxicities. Genetic variability for tolerance to low soil pH exists among maize genotypes, which can be exploited in developing high-yielding acid-tolerant maize genotypes. In this paper, we review some of the most recent applications of conventional and molecular breeding approaches for improving maize yield under acidic soils. The gaps in breeding maize for tolerance to low soil pH are highlighted and an emphasis is placed on promoting the adoption of the numerous existing acid soil-tolerant genotypes. While progress has been made in breeding for tolerance to Al toxicity, little has been done on Mn and Fe toxicities. More research inputs are therefore required in: (1) developing screening methods for tolerance to manganese and iron toxicities; (2) elucidating the mechanisms of maize tolerance to Mn and Fe toxicities; and, (3) identifying the quantitative trait loci (QTL) responsible for Mn and Fe tolerance in maize cultivars. There is also a need to raise farmers' and other stakeholders' awareness of the problem of Al, Mn, and Fe soil toxicities to improve the adoption rate of the available acid-tolerant maize genotypes. Maize breeders should work more closely with farmers at the early stages of the release process of a new variety to facilitate its adoption level. Researchers are encouraged to strengthen their collaboration and exchange low soil pH-tolerant maize germplasm.

Factors Affecting Yield of Crops

“…Low soil pH significantly affects crop growth and therefore decreases yield. In maize for instance, soil acidity causes yield loss of up to 69% [34].…”

Membrane-Bound Class III Peroxidases: Unexpected Enzymes with Exciting Functions

“…So it is very interesting to find peroxidases in these two species that might be involved in this kind of stress. Additionally, this stress can be related to other stresses, like nutrient starvation or drought [ 112 ]. The C2 cluster is build by two PM peroxidases that are involved in plant development.…”

Nutritional Efficiency and Nutrient Acumulation of Maize Cultivated in Soils With High Al-KCl Content

“…The acidity of most Brazilian soils, especially in subsurface horizons (B), limits establishing and developing production systems for a substantial number of crops (Caires et al, 2008). This may be due to toxic Al and Mn concentrations (Bojórquez-Quintal et al, 2017;Tandzi et al, 2018), low exchangeable Ca 2+ and Mg 2+ levels, and low sum of bases (S), base saturation (V%), and P, unfavorable soil properties for growing most crops (Yang et al, 2013;Maluf et al, 2018). However, some soils contain aluminum levels extracted with 1 mol L -1 KCl (Al-KCl) solution exceeding 10 cmol c kg -1 , where plants exhibit no signs of Al 3+ toxicity and obtain satisfactory yields.…”