A comparison of the root and shoot growth of winter barley and winter wheat, and the effect of an early application of chlormequat

Abstract

SUMMARY: In a field experiment where winter wheat and winter barley were sown on the same date, the patterns of root growth of the two species were similar, with a few roots reaching a depth of at least 120 cm. Roots senesced sooner in barley, in association with earlier maturity of the shoots and grain. The number of shoots and leaf area index of the barley were greater than for the wheat, but rates of dry-matter production until anthesis of the barley were similar in both species. The grain yield of wheat was about 10% heavier than for barley. Where chlormequat had been applied in early December at the 3- to 4-leaf stage, when shoot apices of both species were still vegetative, root density of the winter wheat in the following March and April was slightly greater than for untreated plants, but the difference disappeared later. For winter barley there was no effect of chlormequat on root growth until July when root length tended to be greater at depth after the chlormequat treatment. The chlormequat treatment significantly shortened stem length, but did not significantly affect the number of shoots, crop dry weight or grain yield of either species.