Keywords: growth, yield, chlorophyll, drought stress, soil properties and wheat
Triticum aestivum is an important grain cereal with agricultural, economic and nutritional values. Drought stress on the other hand is an abiotic factor that adversely affects the productivity of plants especially those grown in arid and semi-arid regions under conditions of variable soil properties. The aim of this study is to determine the effect of drought stress on five cultivars of wheat under different soil properties selected from North-Central part of Nigeria. Four levels of watering regime (well-watering D1, one weekly drought D2, two weekly drought D3 and three weekly drought D4), five cultivars of wheat (Alta 84 (AL), Atila (AT), Cettia (CE), Norman Bourgluk 2008 (NB) and Seri M82 (SE) and three soil types: loamy sand (S1), sandy loam (S2) and loamy sand (S3) were used in this study. Each treatment was replicated three times; pots were watered till field moisture capacity. Four weeks after planting (WAP), healthy plants were randomly subjected to the drought stress treatments. Fresh plant samples were collected 10 WAP from each treatment for chlorophyll analysis. Experiment was terminated 12 WAP. Soil types and drought stress significantly interacted together to affect the growth (P<0.05), yield and chlorophyll contents (P<0.001) of wheat cultivars. Cultivars Atila (AT) and Cettia (CE) showed highest number of leaves, tillers and spikes, plant height, peduncle and spike length, grain weight, grain number, spike weight, and harvest index at D4. Plant height, peduncle, spike number and spike length were more sensitive to drought stress. Wheat cultivars invested in higher shoot production than root. During drought stress, higher chlorophyll a and total carotenoids were found in cultivar Atila and Cettia at S2 than other soil types. Accumulations of high carotenoids photo-stabilized chlorophyll a in cultivar AT and Ce which prevent them from oxidation damage. Soil type S2 contained high Na+, Mg2+, K+ and Ca2+ with high clay percentage (9.4%) thus, water and nutrients can be retained more at this exchangeable site which may have also contributed to the resistibility of cultivars Atila and Cettia. Therefore, Wheat cultivars Atila and Cettia were considered to be drought-tolerant cultivars. In other to obtain optimal yield, farmers especially in arid and semi-arid regions are to put into consideration the soil composition when cultivating drought tolerant wheats.