A. IVANOVA and N. TSENOV
Dobrudzha Agricultural Institute, BG – 9520 General Toshevo, Bulgaria
IVANOVA, A. and N. TSENOV, 2011. Winter wheat productivity under favorable and drought environments. I. An overall effect. Bulg. J. Agric. Sci., 17: 777-782
The aim of the investigation was to determine the productivity of common wheat genotypes under contrasting environments. The investigated wheat cultivars were grown in two successive years: 2006, which was very favorable for wheat cultivation, and 2007, when one of the most severe and long-lasting droughts in Bulgaria was registered. The genotypes were grown in a complex scheme involving four previous crops and three levels of mineral fertilization, according to the type of previous crop. Grain yield and the following productivity components were studied: 1000 kernel weight, test weight, number of productive tillers, plant height, number and weight of grains per spike. The correlation of grain yield with the related traits was analyzed under contrasting environments. It was found out that the drought in 2007 caused about 30 % decrease of the productivity of the investigated common wheat genotypes. The reduction of grain yield was due to the lower weight of grains per spike (about 40%), the lower number of grains per spike (about 29%) and the smaller size of grains (about 15%). The independent effects of the genotype and the mineral fertilization were much better expressed on the studied traits under the favorable conditions of 2006, and the type of previous crop had significant effect under drought. The relation of grain yield with the number of productive tillers, plant height, weight and number of grains per spike was higher under stress during the growth period of the crop.