54 



BULLETIN 698, U. S. DEPARTMENT OF AGEICULTUEE. 



selves, either in height, or earhness, or in producing power. A plat 

 of Blackhull kafir is shown in figure 9. 



Table XIX shows that in fairly normal seasons, such as those of 

 1908, 1911, and 1915, this variety requires about three months to 

 reach the heading stage and nearly a month more to ripen, making 

 the total duration of the growing period 115 to 120 days. The 

 shortest period recorded is 107 days, for No. 207 in 1908, and the 

 longest is 150 days, for three selections in 1915. Drought may 

 shorten the vegetative period shghtly by checking growth and so in- 

 ducing heading. On the other hand, drought may greatly lengthen 

 this period if it becomes so severe as to inhibit growth altogether 



Fig. 9.— a plat of Blackhull kaflr, C. I. No. 203, at the Amarlllo Cereal Field Station, September 10, 1907- 



until rains occur. This condition occurred in 1916, when the average 

 duration of the vegetative period alone was 128 days and none of 

 the five selections matured. 



The normal height of these varieties under Panhandle conditions 

 is about 5 feet. Drought in early summer reduces this height mate- 

 rially. For instance, in 1910 to 1912, inclusive, the average height 

 was between 4 and 4.6 feet. In 1914 and 1916 the average height 

 fell below 4 feet, while in 1913 the crop was destroyed by drought at 

 an average height of only 2 feet, mostly without producing any heads. 

 In 1915, when the total precipitation was much above normal and the 

 highest yields yet recorded were obtained, the average height was 

 only 5.1 feet. This was due, however, to a somewhat reduced rain- 

 fall in May and June, while growth was being made, and super- 

 abundant moisture thereafter while the grain was being formed. 



