Published online by Cambridge University Press: 27 March 2009
The effects of single and repeated early applications of chlormequat (at up to and including Zadoks growth stage (GS) 32) on the growth and development of the winter oat cultivar Bulwark were investigated in two seasons of field experiments at Tenby, UK. Early dry matter production, shoot initiation and subsequent shoot survival were unaffected by all treatments. At maturity, reductions in stem length and lodging were best achieved by chlormequat applied at GS 32; this treatment shortened stems by an average of 24% in 1985/86 and 31% in 1986/87. Earlier applications were significantly less effective.
Grain yields were unaffected by single and repeated early applications of chlormequat. However, in both seasons, yields were significantly reduced by repeated treatments with chlormequat, including application at GS 32. Individual grain weight was the yield component principally affected.