The development and yield of autumn‐ and spring‐sown barley in south east Scotland

SUMMARY As part of a study of the relationship between plant development and grain yield, winter and spring barleys were sown in the autumn and spring. Apical development and leaf area development were monitored and the final yield was partitioned into grain weight and grain number. The photosynthetically active radiation (PAR) absorbed was calculated. The main differences found were between sowings rather than between genotypes within sowings. The autumn sowing outyielded the spring sowing because the grains were heavier, although the autumn sowing tended to have fewer grains m‐2. In the autumn sowing the rate of initiation of spikelet primordia was slower, due to the lower temperatures encountered, but the initiation phase lasted longer and a larger proportion of primordia survived. However, the increased proportions of tillers to mainstem reduced the mean number of grains/ear. The numbers of grains m‐2 and the yield were related to the PAR absorbed. In this analysis the earlier anthesis of the autumn‐sown plants could be seen to be reducing the PAR absorbed and consequently the grains m‐2.