EFFECT OF LATE-SEASON FUNGICIDE APPLICATION ON GRAIN YIELD AND SEED SIZE DISTRIBUTION IN WHEAT AND BARLEY

Abstract

Field trials were conducted to determine the effect of foliar fungicides on grain yield, kernel size and seed size distribution in wheat and barley. Tilt (propiconazole) was applied at 125 g a.i. ha−1 between Zadoks growth stages 49 and 59. Following harvest, seed samples from treated and untreated plots were stratified into different size classes. In barley trials, net blotch was the most prevalent leaf disease while in wheat trials, tan spot, leaf rust and Septoria leaf spot were most prevalent. Under high levels of disease, Tilt reduced the level of disease and significantly increased grain yield and the amount of large kernels in both wheat and barley. Under low levels of disease, Tilt rarely increased grain yield, but frequently increased the amount of large kernels. In barley, the increase in amount of seed in the larger size classes across all sites was correlated (P < 0.05) with reduction in net blotch severity. No significant effect of Tilt on germination at 5 °C was observed for any of the wheat cultivars considered in this study. Increases in the yield of large kernels indicate that late season applications of fungicide may be useful in pedigreed seed production, where large kernels are desired.Key words: Seed crops, kernel weight, seed vigor, tan spot, Septoria, net blotch