Response of twelve corn cultivars to soil water deficit in a Dark-Red (typic haplustox) Latosol from the “Cerrados” of the Federal District, Brazil

Abstract

A field experiment to compare the response of twelve cultivars to soil water deficit was conducted during the dry season of 1980. The study indicated that best yields under permanent irrigation were obtained with corn (Zea mays L.) cultivars Cargill 111 (6.025 kg/ha > Ag 301 = Ag 259 =Ag 401 = CMS 01. After a drought of 31 days (tank A evap. 170 mm), best yields corresponded to cultivars Ag 259 (3.976 kg/ha) = CMS 08 = Ag 401 = Cargill 111 = Ag 301. General average yield under permanent irrigation and soil water deficit conditions, were 4.557 and 3.192 kg/ha, respectively. There were not significative effects of soil water regime on the cultivars in relation to number of cobs/plant or cobs weight. Accumulated evapotranspiration of cv. Cargill 111 reached 515 mm. All the cultivar, started to diminish their evapotranspiration after 12 to 15 days of drought. After 20 days of drought, it diminished from 5,75 to 1,90 mm/day. All the cultivars presented similar root distribution. Eighty to ninety per cent of corn root weight was found in the upper 20 cm of the profile. No effect of soil water regime on root density of the different cultivars was observed.