Evaluating wheat, barley and oats for early sowing under frost-prone field condition in Southern Australia

Abstract

Low temperatures during the flowering period of cereals can lead to floret sterility and yield reduction, resulting in economic losses in Australian crops. In this study, we investigated the relative suitability of wheat, barley and oat in a frost-prone landscape. In addition, we analysed across the sowing program the most stable and profitable cereal (i.e. gross margin). We tested the hypothesis that wheat was as profitable as barley and oat when phenology matched the optimum time of sowing. Yield and yield components, and floret sterility were measured, while gross margins were calculated. The factorial experiment combined six wheat, three barley and three oat varieties under three sowing dates (19th April, 4th May, and 22nd May 2017). Results suggested that long-maturity varieties were best suited to an early sowing time (mid-April). Kittyhawk (wheat), Urambie (barley) and Banister (oat) avoided frost damage during the critical period around anthesis. Later sowing was best suited to short-maturity types such as La Trobe (barley) and Cutlass (wheat). Oat was not economically viable in the frost-prone trial region, returning a negative gross margin across all sowing times. While heat and drought stress were not quantified in this study, these abiotic stress constraints play a crucial role during the grain filling stage; and as such can have a profound effect on the final number of grain number m-2 and therefore grain yield.