Improvement of growth and yield of bread wheat by means of chemical manipulation under glass house
In this study, attempts were made to investigate the growth and yield performance of a Bangladeshi bread wheat cultivar (Sonalica) under the influence of three different nitrogen fertilizer levels and one concentration level of ComCat ® , a commercial bio-stimulant, applied either as a seed treatment before planting or as a foliar spray on seedlings at the 3- leaf growth stage, under glasshouse conditions. Initially the South African (RSA) standard N-level for winter wheat was taken as the medium N- level together with a down scaled (low) and an up scaled (high) rate during the 2001 season in order to ascertain the optimum level. However, it was observed that the Bangladeshi cultivar could not tolerate the RSA standard (medium rate) for nitrogen application. After germination all plants fertilized with the medium and high nitrogen rates, died off. Subsequently, this N-level was taken as the medium level for the 2002 trial and a new down scaled (low) and up scaled (high) N-level was calculated and applied, together with the two ComCat ® treatments. Overall, even though the nitrogen fertilizer application was scaled down substantially during the 2002 growing season, the response of this bread wheat cultivar, in terms of growth and yield, was more positive at the lowest N-level. Results obtained during 2002 consistently confirmed that the application of ComCat ® , especially as a foliar spray at stage 13 of seedling development, affected the vegetative growth of plants. However, the enhancing effect of the bio-stimulant was more pronounced on yie ld, in terms of both the increase in number of kernels and kernel dry mass per plant. Finally, the results of this study and several previous unpublished reports strongly indicate that application of a bio-stimulant such as ComCat ® , in combination with an optimum nitrogen regime, can result in the improvement of yield under glasshouse conditions. In future research attention should be given to the combined effect of ComCat ® and other macro-nutrients, as well as the potential to decrease fertilizer applications when a bio-stimulant is applied in combination, under field conditions.