Acid soils in the world cover 30% of the total ice-free land area (3,950 million ha). Oxisols and ultisols are the most frequent acid soils in South America, covering 800 million ha in Brazil (70.9%), Colombia (8.3%), Peru (6.9%), Venezuela (6.4%), Bolivia (4.9%), Paraguay (1.2%), Ecuador (1.1%) and the remainder in the other countries (Von Uexkull and Mutert 1995; Cochrane 1979).Main limiting factors for maize production in these soils are low pH, Al toxicity, and phosphorus deficiency; however insects and diseases also cause important losses. Consequently, any strategy to increase maize production in these areas would include the development of acid soil maize cultivars that respond to a reasonable use of amendments and are tolerant to important diseases and pests. This is one of the objectives of the CIMMYT's South American Regional Maize Program (SARMP). Average maize production in the Colombian savanna, the major acid soil area in this country, is less than 0.5 t/ha using maize landraces. Yield potential of acid soil-tolerant open pollinated varieties (OPVs) and hybrids developed by CIMMYT and national agricultural research programs is 3 t/ha and 4.5 t/ha, respectively. The objectives of this study were to generate OPVs with tolerance to acid soils and tolerance to maize diseases in the tropics and evaluate these OPVs in acid and non-acid soil environments.

Global Maize Program

English

0311|AGRIS 0301|AL-Maize Program

Juan Carlos Mendieta

INT2062

CIMMYT Staff Publications Collection