Hulless barley seeding rate effects on grain yield and yield components
Recent efforts to expand markets for winter barley (Hordeum vulgare L.) in the mid-Atlantic have focused on hulless types due to higher energy density. The exposed endosperm of hulless barley makes damage more likely than with hulled barley, and emergence is typically lower. Information to determine the optimum seeding rate for winter hulless barley is presently unavailable. Experiments were conducted over six site-years in Virginia to evaluate seeding rate effects on grain yield and yield components of six hulless and three hulled barley lines. Seeding rates ranged from 278 to 742 viable seeds m–2. At similar seeding rates, final plant stands for hulless lines were 75% of that for hulled varieties. At equivalent plant density of 320 plants m–2, average grain yield for hulled lines was 6000 kg ha–1 and 4500 kg ha–1 for hulless lines. Yield of the best hulless barley line was 80% that of the hulled lines. A large portion of this is attributable to lower individual kernel weight, due to the absence of the hull weight. Hulless barley lines also had 5% fewer heads per square meter and 29% fewer grains per head. Seeding rates for hulless barley in a conventional, tilled seedbed should be at least 400 seeds m–2 to approach optimum yields. These results also support the conclusion that seeding at 480 to 520 seeds m–2 is appropriate for sites with high yield (5000 kg ha–1) potential.