DEVELOPMENT OF BARLEY KERNELS IN NORMAL 

 AND CLIPPED SPIKES AND THE LIMITATIONS OF 

 A.WNLESS AND HOODED VARIETIES^ 



By Harry V. Harlan, Agronomist in Charge of Barley Investigatiotts, and Stephen 

 AutnONV , formerly Technologist in Barley Investigations, Office of Cereal Investi- 

 gations, Bureau of Plant Industry, United States Department of Agriculture 



INTRODUCTION 



The studies reported in this paper were made in an effort to obtain 

 some light on one of the farm problems in barley production. Among 

 the farmers of the United States there is a strong prejudice against the 

 growing of barley because the long, rough awns make the crop disagreeable 

 to handle. The beards in barley straw and hay often cause sore mouths 

 in stock. Barley straw and barley hay are also undesirable for feeding 

 to sheep because the awns work into the wool. It is only the high acre 

 yield in pounds of feed that has maintained the acreage of this crop, 

 but this acreage is far below that which would be devoted to barlev if 

 the awns were lacking. 



Certain types of barley are free from the harsh awns. One of these, the 

 Nepal, produces hoods in the place of awns. This variety, under various 

 names, has been more frequently introduced and more widely tested than 

 any other. Many hybrids have been made and distributed. That they 

 have failed to measure up to the expectations is evident in the annual 

 inquiry of seedsmen as to where they can secure seed of "bald" barley. 



The only apparent explanation of the failure of the Nepal barley is the 

 lack of awns. The field records of the Office of Cereal Investigations, 

 extending over many years, indicate that the Nepal compares favorably 

 with other varieties only in the high altitudes and in dry years in the 

 northern part of the Great Plains area. As a rule, varieties of this type 

 have yielded less than the awned sorts and have shattered badly. It is 

 evident that the awn is an organ that is functional under most conditions, 

 and especially in those sections where humid weather prevails at ripening 

 time. 



Zoebl and Mikosch ^ in 1892 showed that the awn of barley was an 

 organ of transpiration. Schmid ^ in 1898 and Perlitus * in 1903 elabo- 

 rated the experiments of Zoebl and Mikosch. All agreed that the awn was 

 an organ of transpiration and all showed the effect of its removal on both 

 the rate of transpiration and the kernel. 



• These studies were made on the Aberdeen Substation, Aberdeen, Idaho, in connection with cereal 

 experiments conducted cooperatively by the Idaho Agricultural Experiment Station and the Office of 

 Cereal Investigations, Bureau of Plant Industry, United States Department of Agriculture. 



2 Zoebl, A., and Mikosch, C. die function der grannen der gerstenahre. In Sitzber. K. Akad, 

 Wiss. [Vienna], Math. Naturw. Cl., Bd. lor, Abt. i. Heft 9/10, p. 1033-1060. 1892. 



'Schmid, B. BAtJ und funktionen der grannen unserer getreidearten. In Hot. Centbl., Bd. 

 76, p. 39. 75. 119. 218, 305-307- 1898. 



* Perlitus, Ludwig. einfluss der begrannung auf die wasserverdunstxjng der aehren und 

 DIE kornqu/xiTAT. 77 p., 3 pi. Breslau, 1903. 



Journal of Agricultural Research, Vol. XIX, No. 9 



Washington, D. C. Aug. 2, 1920 



ur (431) Key No. G-200 



