EFFECT OF LATE NITROGEN ON THE YIELD AND QUALITY OF SPRING SOWN RONGOTEA WHEAT

Three experiments were conducted at different sites in the Manawatu, New Zealand, to investigate the effects of late nitrogen (N) on the yield and baking quality of 'Rongotea' wheat. Four rates of N were applied: 0, 20, 40, and 80 kg N/ha applied at Feekes' Growth Stage 9. Late N increased grain yield at two sites. Yield responses resulted from an increase in ears/M2 at one site and grain weight at the other. Grain protein % was increased by late N at all sites. Mechanical Dough Development (MDD) bake score, sodium dodecyl sulphate (SDS) sedimentation volume, water absorption, and optimum work input were all positively correlated with grain protein. The regression of SDS sedimentation volume on grain protein % was calculated for each site individually and also with data from all sites pooled. There were differences between the regressions from individual sites and the pooled regression indicating that site influenced the relationship between baking quality and grain protein %.