Browsing by Author "Shandu, Minenhle"
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- ItemThe influence of zinc content on wheat seed quality and vigour(Stellenbosch : Stellenbosch University, 2021-12) Shandu, Minenhle; Pieterse, P. J.; Stellenbosch University. Faculty of AgriSciences. Dept. of Agronomy.ENGLISH ABSTRACT: It is the objective of every farmer to obtain high yields and therefore the use of good quality seeds is of importance. Most soils that support wheat cultivation are zinc (Zn) deficient. Biofortification was shown to be a solution to improve mineral content (particularly Zn) of cereals. Improved Zn content has secondary benefits during seedling development under Zn deficient conditions. On the other hand, yields are limited by other factors such as weeds, soil borne diseases and environmental stresses such as extreme drought conditions. All these factors reduce productivity of wheat, which have implications for global food demand to meet a growing population. The use of seeds with high vigour ensure investment returns because these seeds are believed to have better germination and tolerance against biotic and abiotic stresses. This study aims to investigate the influence of seed Zn levels on vigour of wheat accessions with varying quality attributes. Seed Zn has been associated with improving agronomic traits such as germination and optimum field emergence. The influence of seed Zn was investigated through laboratory and field experiments. Vigour was determined using the EC test, standard germination test, according to ISTA and accelerating ageing test (AA). Field experiments were conducted at two different localities, namely Langgewens and Roodebloem, respectively. Proper mineral content is vital for germination and zinc has been reported to improve vigour of seeds. The electrical conductivity (EC) test provided the best estimate of seed vigour, R1H (51.3 mg kg-1) had the least electrolyte leakage as well as, the best germination (>80%). Results indicated that seed vigour is affected by age, seed Zn concentration and locality of the seeds and their weight. Adequate Zn in wheat is an essential micronutrient required during physiological processes like germination. Accessions were one year apart with optimal germination from one-year old accessions. Due to natural ageing or artificial ageing, seeds lose vigour over time. The potential of using Zn-biofortified seeds still need to be investigated further because some of the accessions which had low zinc content managed to perform similarly to high Zn content accessions. Increasing sowing depth had a significant effect (p>0.05) on germination and emergence of wheat. This study revealed that seed Zn is beneficial to a seedling during early development. In field experiments and despite variation in seed Zn concentrations, both experiments at Langgewens and Roodebloem had uniform canopies at harvest. The benefits of high seed Zn content were inconclusive. Zinc biofortified seeds had an advantage of better germination and good establishment under different environmental conditions. However, the benefits of high seed Zn concentrations seemed to be sensitive to the availability of Zn in the soil. Zinc plays a crucial role in early stages from germination to emergence and early growth stages (tillering) but does not seem to influence the growth of wheat at later growth stages.