Masters Degrees (Agronomy)

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Browsing Masters Degrees (Agronomy) by Author "Bagwasi, Gaesejwe"

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    Response of wheat (Triticum aestivum L.) and barley (Hordeun vulgare L.) to salinity stress
    (Stellenbosch : Stellenbosch University, 2015-12) Bagwasi, Gaesejwe; Agenbag, G. A.; Stellenbosch University. Faculty of Agrisciences. Dept. of Agronomy.
    ENGLISH ABSTRACT: Good quality water for agricultural use is rapidly becoming a luxury due to competition for this water among the municipal, industrial and agricultural sectors. This has often forced growers to use poor quality water for irrigation. Salinity is one of the main sources of poor water quality and high electrical conductivities (EC’s) due to salinity may become a problem. The aim of this study was to compare the response of South African spring wheat and South African spring barley at germination, seedling growth, vegetative growth, reproductive growth and maturity stage to salinity stress caused by irrigation with saline water. This study was conducted in the laboratory and under controlled glasshouse conditions at the University of Stellenbosch in the Western Cape Province of South Africa. Treatments in trial 1 (incubation trial) were made up of three wheat cultivars (SST 027, SST 056 and SST 087) and three barley cultivars (Nemesia, Erica and Hessekwa) exposed to five EC levels of NaCl solutions (4, 8, 12, 16 and 20 dS m-1) and a control (0 dS m-1) of distilled water, during the germination phase. In trial 2 (pot trial), wheat cultivar SST 027 and barley cultivar SVG 13 were also subjected to the above solutions, but plants were grown till the tillering stage. In trial 3 (pot trial) cultivars used in trial 2 were subjected to five nutrient solutions with EC levels of 1.6, 3, 6, 9 and 12 dS m-1 and allowed to grow till maturity (harvesting stage). Fully balanced nutrient solution with EC = 1.6 dS m-1 was used as a control and NaCl was added to the solutions to obtain the needed EC. In trial 1, final germination percentage (FGP), salt tolerance (ST) and germination rate (GR) were measured at 7 days after incubation. The study showed that when the EC level was increased, FGP, ST and GR of all wheat and barley cultivars tested were decreased. However, significant reduction was only observed at high EC levels with regard to FGP and ST. Wheat cultivars recorded faster GR compared to barley cultivars and tended to be less sensitive to salinity in the germination stage. Cultivars from the same species did not show significant differences. In trial 2, shoot length (SL), root length (RL), shoot fresh weight (SFW), root fresh weight (RFW), shoot dry weight (SDW) and root dry weight (RDW) were measured at 35 days after planting (DAP). In general, the study showed that salinity had a significant (P0.05) effect on seedling growth of all measured parameters of both wheat and barley. Mean values for most growth parameters were higher for barley cultivar SVG 13 as compared to wheat cultivar SST 027. However, little evidence was found to show that barley is more salt tolerant than wheat at the seedling stage. In trial 3, selected growth parameters were measured at tillering (28 DAP), booting (54 DAP), flowering (71 DAP) and maturity stage (150 DAP). The study showed that salinity had a significant (P0.05) effect on the vegetative growth, reproductive growth and grain yield of both wheat and barley. Although barley generally produced higher dry weights especially at the early growth stages no clear evidence was found that South African spring barley is more salt tolerant than South African spring wheat.