Effect of cultivar and temperature on the coleoptile length and establishment of barley

Abstract

Laboratory experiments were conducted to determine the effects of 7 cultivars and 8 constant temperatures on the coleoptile length of barley seedlings grown in darkness. A field experiment was used to determine correlations between laboratory measurements on seed (coleoptile length, germination and weight) and barley establishment after deep sowing (at 80 and 110 mm). Cultivar and temperature both affected coleoptile length. Cultivars in order of coleoptile length were Orge Saida > Prior > Clipper > Schooner, Grimmett >Grit > Lada. Coleoptiles were longest (61-106 mm) at 10-20¦C and shortest (28-36 mm) at 35-40¦C. The cultivar x temperature interaction was significant (P<0.01), differences in coleoptile length among cultivars being greatest at low temperatures. Laboratory germination gave the best prediction of barley establishment for the sowing depth of 80 mm (adjusted R2 = 0.47), and coleoptile length and seed weight the best predictions for the sowing depth of 110 mm (adjusted R2 = 0.93 and 0.83 respectively). Strategies for improving barley establishment from deep sowings include cultivar selection, seed selection, selection of sowing time to suit seedbed temperatures and the use of seeding machinery which forms furrows directly over rows of deeply sown seed.