L. M. P. Rocha

Grain yield and water use efficiency of genetically modified corn in contrasting climatic conditions in Teresina - PI, Brazil

The climate adaptation of any plant species is closely related to its phenology, influencing on its geographical distribution and its fluctuation in ecosystems. The objective this work was to evaluate the performance of 33 hybrids (26 single hybrids, six triples hybrids and one double hybrid) genetically modified corn in contrasting climatic conditions (two sowing dates) under irrigation. The experimental design was a randomized complete block design with two replications. The experiments were sown in the Embrapa Mid-North, Teresina, Piauí State, in July and September / 2013. The average maximum temperature from bolting to heading during the first season was 36.7 °C and in second one was 38.8 o C, reducing the water use efficiency (WUE) and yield components, ear number per area and ear weight in september sowing. The grain yield and WUE of sowing June (9,876 kg ha -1 , 17.3 kg ha -1 mm -1 ) was higher 25.1% and 42.27%, respectively, compared to sowing September (7,900 kg ha -1 , 11.97 kg ha -1 mm -1 ). AG 8041 PRO, P 3646 HX, RB 9221 PRO, P 4225 H, 30 F 53 YH hybrids present tolerant to high temperatures and more efficient water use.