Seed productivity and seed quality of two Sarepta mustard cultivars under different zinc concentrations in the root environment

Currently, in Russia and other countries, the areas under Sarepta mustard (Brassica juncea (L.) Czern.) are increasing, which is associated with its multi-purpose use, as well as good adaptation to adverse environmental factors. The ability of Sarepta mustard to grow on soils with increased zinc concentrations is also known. At the same time, the content of this metal in plant seeds is usually low due to the effective operation of its detoxification mechanisms. This suggests the possibility of growing Sarepta mustard for seeds on soils with a high zinc level. In this work, the effect of different zinc concentrations (5, 50, 100 and 150 mg/kg of substrate) on seed productivity and seed quality of two Sarepta mustard cultivars (‘Slavyanka’ and ‘Zolushka’) was studied. The research was carried out in a sandy substrate under vegetation experiment conditions. It has been established that high zinc concentrations have a greater effect on the weight and number of seeds, and a lesser effect on the pods number and 1000 seeds weight. Thus, at a zinc concentration of 150 mg/kg of substrate, the number and weight of seeds in the ‘Slavyanka’ cultivar were 2 times less than in the control. In the ‘Zolushka’ cultivar even at zinc concentration of 100 mg/kg of substrate both parameters were 4 times lower than in the plants of the control variant. Based on the results, a number of seed productivity parameters were compiled according to the degree of zinc negative effect on them. It was also revealed that the quality of the formed seeds, determined by the germination energy, seed viability and the initial growth, was high in all variants regardless of the zinc content in the substrate. Moreover, the seeds were able to germinate successfully even on a "provocative background" – a high zinc concentration (1000 μM). The ‘Slavyanka’ cultivar turned out to be the most resistant to high zinc concentrations. A conclusion was made about the possibility and prospects of using Sarepta mustard for growing seeds on zinc-contaminated soils.