Water relations and productivity of two lines of pearl millet grown on lysimeter with two different soil types

摘要

Crop water productivity is one of the important aspects of water use of crop, most especially where water is a limiting factor. This study was carried out to assess and compare water relations and productivity of two lines of pearl millet grown on lysimeters with two soil types. The study was carried out at the lysimeter unit of the Department of Soil, Crop and Climate Sciences Experimental Farm, Kenilworth, University of the Free State, Bloemfontein. One row of the unit contains a Clovelly soil and the other row, Bainsvlei soil. The two lines of pearl millet used for the study were GCI 17, improved variety and Monyaloti, a local variety. Irrigation treatments were applied such that water was withheld at the beginning of different growth stages of the crop to impose water stress. These treatments were well-watered (WIN), vegetative stage stress (VS), reproductive stage stress (RS), and grain-filling stage stress (GS). The treatments were replicated two times per line of pearl millet per soil type. The results show that the lowest leaf water potential was observed in the GS stress plants for both lines of pearl millet on Bainsvlei soil form. The highest stomatal conductance observed on Clovelly soil was around 400 mmol m(-2) s(-1) while it was around 300 mmol m(-2) s(-1) on Bainsvlei soil for the two lines of pearl millet. The highest and lowest grain yields for GCI 17 were from Clovelly soil. The highest grain yield for Monyaloti was 10.74 t ha(-1) from the WW found on Clovelly soil type while the lowest was 3.93 t ha(-1) from GS found on Bainsvlei soil type. The mean water productivity for biomass (WPbm) of GCI 17 was 0.036 t ha(-1) mm(-1) for both soil types while Monyaloti had WPbm of 0.037 and 0.035 t ha(-1) mm(-1) on Bainsvlei and Clovelly respectively. Clovelly soil type proved to exhibit high water productivity for grain yield production of pearl millet.