Visual assessment of grain yield and its components in single plants and ears of spring barley

Visual assessments of yield/plant and tillers/plant were more effective than unaided assessments of grains/ear and 1000-grain weight on a per plant basis. Assessments of the latter yield components were generally improved by the use of specially developed keys described by Ismail & Valentine (1983). Gains in efficiency were associated with the amount of extra time spent on making these assessments. Assessments of yield/ear were not more effective than assessments of yield/plant. This was attributed to the ease of assessment of tillers/plant which was strongly associated with yield/plant. Assessments of grains/ear and 1000-grain weight in single ears were clearly more effective than corresponding assessments in single plants in which there is high variability between ears. Apart from using keys, further improvements in the assessments of grains/ear and 1000-grain weight are necessary in order to increase the effectiveness of single plant selection in the F₂ generation which is the first opportunity of increasing yield in later generations.