WATER INDEX OF TWO MAIZE CULTIVARS UNDER TWO SEED SYSTEMS

Abstract

This trial was realized at El Ejido, Los Santos, with the objective of determining the water index of two maize cultivars (hybrid and variety) through the plants temperature, under two planting systems (irrigation and rainfed). Samples were taken every 10 days with a digital infrared thermometer to determine foliage and soil temperatures. Soil humidity was determined by gravimetry method, tensiometer and humidity measuring bulbs. Chlorophyll content was measured with a chlorophyll meter. Water index, as the difference between crop and air temperatures. Water index and hybrid biomass under rainfed conditions were correlated (R²= 0,79). The less the index, the largest the biomass percentage. At the same stage, water index and chlorophyll content were also correlated (R²= 0,53). There was observed a tendency to an increase in soil temperature as water index increasing. Maize variety similarly; water index was correlated to biomass percentage and chlorophyll content, with R² of 0,53 and 0,70 respectively. Yields of hybrid and variety, planted in August under irrigation, were superior to those obtainedunder rainfed conditions. For October plantings, yields of both cultivars were very similar under irrigation and rainfed conditions.