COLEOPTILE LENGTH AND EMERGENCE IN VARIETIES OF BARLEY, OATS, AND WHEAT

Coleoptile length and seedling emergence were studied in barley, oats, and wheat, with four varieties for each crop. Significant differences in coleoptile length were obtained in darkened cabinets between varieties of barley and oats with temperature regimes of 8 and 21 °C, and between varieties of wheat at 8 °C. In greenhouse tests with seeding depths of 2.5, 5.0, and 7.5 cm, there were significant varietal differences in barley in both coleoptile length and emergence. The differences in coleoptile lengths in oat and wheat varieties were not considered important as there were no resulting variations in emergence. The significant effect of seed size on coleoptile length noted in barley was considered of doubtful practical importance.With barley in three soil types, marked varietal differences in coleoptile length and emergence were found in a soil low in humus, at the 7.5 cm depth. Out of 50 seeds sown, an average of only 12 seedlings emerged for the variety with the shortest coleoptile, while 28 emerged for the one with the longest coleoptile. As moisture conditions dictate varying depths of seeding, these results suggest that coleoptile length be considered in barley breeding programs.