Development of Hulless Barley Varieties
as an Improved Feed Crop
R.L. Paris, C.A. Griffey, and M.E. Vaughn
Virginia Polytechnic Institute and State University
The hulless barley project was conducted to determine the potential of hulless winter barley (Hordeum vulgare L.) as an improved feed crop in the mid-Atlantic region. Winter barley is an excellent crop in rotation with soybean (Glycine max L.) in the mid-Atlantic region. However, production of winter barley during the past few years has decreased mainly due to low market prices, even though the mid-Atlantic region is considered a feed grain deficient area. Therefore, value added traits need to be developed in order for barley production to continue in the region.
The first part of this study was conducted to: (i) evaluate the agronomic performance and potential of six experimental hulless winter barley lines compared with two commercial hulled cultivars; (ii) determine and compare fiber, -glucan, protein, and fat concentrations, and tue metablolizable energy, corrected for nitrogen (TMEn) among these genotypes; and (iii) evaluate the genetic potential of winter hulless barley accessions from the world collection for use as parents in hulless breeding programs. The hulless lines yielded less, but had higher test weights than the hulled check cultivars. Hulless lines had a higher protein and lower fiber concentration than hulled barley and a higher -glucan and fat concentrations than triticale or wheat. There was no difference in TMEn between hulled and hulless barley, triticale, or wheat; however, hulless lines tended to have higher values than hulled cultivars. The world collection of hulless winter barley was planted in headrows for agronomic evaluation. Approximately 100 lines were selected for use as parents among 800 accessions tested , based on evaluation of lodging, plant height, threshability, and seed color.
The second part of the study was conducted to determine the effects of (i) hulled and hulless barley and (ii) -glucanase on the performance of broiler chicks fed different diets from 21 to 42 days of age. Diets comprised of 30% hulless or hulled barley, and a standard corn/soybean meal diet with and without -glucanase enzyme were evaluated to determine the effects of barley on gut viscosity, carcass weight, gain, percent shell, and feed efficiency in 21 to 42 day old broiler chicks. In the first year, diets comprised of hulless line SC890573 and SC860972, and the hulled cultivar Callao were compared to a standard check diet. In the second year SC860972 was replaced with SC880248 due to the inability to secure a sufficient amount of seed. Each year two hulless and one hulled barley diets were compared to a standard diet, each fed with and without enzyme, for a total of eight diets fed. Broiler chicks 21 days of age were fed the diets until day 42 when they were processed. There was a significant decrease (P0.05) in gut viscosity of birds fed diets with enzyme compared to birds fed diets without enzyme; however, gut viscosity did not affect weight gain or percent shell. Barley substituted at the 30% level did not have a significant effect on broiler performance, nor did the addition of enzyme. Absence of enzyme effect was attributed to bird age, since older birds are able to hydrolize -glucan more effectively than juveniles.
The potential of hulless barley as an improved feed source for the poultry and swine industry is great for the mid-Atlantic region. Increases in yield are currently being realized through focused breeding efforts, and hulless lines exhibit positive nutritional components that combine favorable attributes of both wheat and hulled barley. Also, barley substituted at the 30% level in the diets of broilers did not cause any detrimental effects, addition of barley may potentially lead to a reduction in cost per pound of gain of broilers.