Short CommunicationThe effect of bacterial-based biofertilisers and cytokinin on the emergence of sunflower at non-limiting and supra-optimal temperatures

Abstract

Subsurface sunflower (Helianthus annuus L.) seedling growth often deteriorates on sandy-textured soils due to supra-optimal temperature levels on the Highveld area of South Africa leading to poor emergence and suboptimum plant population densities. It has been shown that seedling growth is enhanced by the application of plant growth promoting rhizobacteria and cytokinin. The possibility therefore exists that the poor emergence problem might be remedied through the use of these applicants. The objective of this investigation was to determine if commercially available bacterial-based biofertilisers and cytokinin can enhance the seedling vigour of subsurface sunflower seedlings in controlled ambient temperatures ranging from non-limiting to supra-optimal and in unregulated field conditions. The results suggest that there are conditions where bacterial-based biofertiliser and cytokinin can alleviate the damaging effect of supra-optimal temperatures on the emergence of sunflower. However, the effect of these applicants on various cultivars and soil conditions require further investigation.

Keywords: biofertiliser, cytokinin, emergence, sunflower, temperature

South African Journal of Plant and Soil 2014, 31(4): 233–235