FIELD CROPS. 139 



The introduction of foreign varieties into Bavaria caused a marli:ed reduction 

 in the weight of the grain during the first year these varieties were grown 

 under the new conditions. In later years variations in the weight of the grain 

 were similar to those occurring in the standard sorts. Five years after their 

 introduction, varieties related to the native sorts showed no difference in the 

 grain weight, but the improved heavy grained North German varieties retained 

 in part at least their characteristic heavy weight of the grain as long as the 

 eighth year of their culture in Bavaria. A gradual approximation of the grain 

 weight of the native oats, however, was apparent. The variation in the size of 

 the grain was controlled in general by the amount of precipitation during the 

 period the kernel was forming. 



The weight of the hulls of the inner grains was from 5 to 10 per cent lower 

 than the weight of the hulls of the outer grains. A difference sometimes 

 amounting to 3 per cent was observed in the weight of the hulls of the awned 

 and the awnless outer grains, those of the awned grains being the heavier. In 

 most of the improved varieties examined, the hulls were not so heavy as in 

 the common varieties. During the first 2 years the hull content in the highly- 

 bred varieties varied in a manner similar to that in the native standard sorts, 

 but in Fichtelgebirg oats the hull content inci'eased considerably during the 

 first and second year after its introduction at Weihenstephan. The hull con- 

 tent was not found to be a very constant variety character. 



In studying the length of the grains it was observed that the inner grains 

 were about 15 per cent shorter than the outer ones and the awnless outer grains 

 about 5 per cent shorter than the awned. All introduced varieties grown at 

 Weihenstephan lengthened their grains. In the common varieties this length- 

 ening took place during the first and second years of their culture in the new 

 environment, while the improved varieties followed in a measure the variations 

 in the domestic sorts, attaining the greatest grain length in the same seasons. 

 The yearly variation in the length of the grain was greater in the common 

 than in the improved varieties. The variations in the length of the inner grains, 

 as a rule, was not so marked as in the outer grains. The length of the grains 

 was increased when the precipitation decreased during the time the grain was 

 developed. 



The inner grains of the spikelet were found to be shorter than the outer ones 

 and the awnless outer grains shorter than the awned. During the first years 

 of the experiment at Weihenstephan all introduced varieties showed an increase 

 in the length of the hull and the kernel, the greater increase being made by 

 the improved as compared with the common varieties. The maximum kernel 

 length in the common varieties was attained during the second year of the test, 

 while the highly-bred varieties varied in this particular very much like the 

 standard varieties. The third year all varieties approached the standard 

 variety in length of kernel. The variations in the length of the inner kernels 

 of the spikelet were more marked than those of the inner grains and those of 

 the outer kernels. Long grains were correlated with short kernels. The tip of 

 the inner grains was in general absolutely and relatively smaller than the tip 

 of the awnless outer grains, but in the awned grains it was larger than in the 

 outer ones. The awned grains were in all cases thicker than the awnless but 

 the difference was seldom more than 0.1 mm. The common varieties in general 

 had thinner grains in the original seed and the later crops than the improved 

 sorts. The thickness of the grain varied in the same manner as the length. 

 With reference to the width it was found that grains in the common varieties 

 were narrower than those of the improved varieties. This was true of the 



20872— No. 2—10 4 



