Utilization of physiological traits for selection of high-yielding double haploid barley

There is an increased interest in developing high-yielding hulless feed bar ley (Hordeum vulgare L.) with low fibre content for swine rations. However, little information on physiological basis to select for high-yielding hull ess barley was available. Approximately 400 double haploid barley lines wer e derived from a Kunlun No. 1/CIMMYT No. 6 cross using the bulbosum method. Both parental lines were six-row feed barley types differing in seed type, leaf type, leaf area distribution, tillering, time to heading and maturity and grain yield. Although Kunlun No. 1 yielded about 66% of CIMMYT No. 6, its seed was hulless with a grain weight 21% larger than covered CIMMYT No. 6 seed. Hulless barley, with its reduced fibre content, is desirable in sw ine rations. Selected double haploid lines (100 covered lines in 1995 and 1 00 hulless lines in 1996), parental lines and an adapted check, Chapais wer e evaluated at Ottawa, ON, and Charlottetown, PEI. We found that grain yiel ds were significantly correlated with leaf area index (LAI), dry matter (DM ), length and width of flag leaves, and plant height. All of the highest yi elding lines in both hulless and covered populations common to both sites w ere similar to the parent Kunlun No. 1 with broader, shorter and greener le aves than the parent, CIMMYT No. 6. The best covered lines yielded more tha n the check cv. Chapais and some of the hulless lines were similar to the c heck. This study suggests that selection of high-yielding low fibre double haploid barley lines based on physiological traits has potential to increas e,grain yield for feed barley.