PRACTICUMS FUR WHEAT 



i3» 



cultivation. In addition, its wide adaptation to different soils 

 and climate has made it one of the principal foods of mankind 



Practicums. 



195. Study of the Spike of Wheat. — Request each student to report the 

 i^llowing, after examining a head of wheat: 



1. Number of spikelets in the spike of wheat 



2. Number of flowers in each spikelet. 



3. Number of grains in the whole spike. 



4. Determine the number and arrange weight of grains occupying first, second. 



third and fourth place from rachis. 



5. Number of empty glumes in a spikelet. 



6. Make a sketch of the beak, shoulder and auricle of the empty glume. 



7. How does the flowering glume differ from the palea ? 



8. How is the spikelet attached to the rachis ? 



9. Draw the rachis. 



The spikes of wheat should be laid between pieces of moistened blotting paper 

 for several hours before handing the students, in order to toughen the parts. 



196. Method of Cross-Fertilization, — In order to effect cross-fertilization, 

 the anthers must be removed from all the flowers on the 



spike, before any of them have shed their pollen. This 

 can best be done when or before the anthers are slightly 

 tinged with yellow. The labor may be reduced by re- 

 moving all but one or two dozen flowers. If spikelets 

 on the middle portion of the spike are left and only the 

 two lower flowers of the spikelet, more uniformity in 

 the maturation of the flowers will be obtained, as well 

 as more uniformity in other particulars. After care- 

 fully removing the unbroken anthers, the emasculated 

 spike may be protected by wrapping about it a piece of 

 tissue paper and tying it above and below. One to two 

 days later the flowers will open, which may be told by 

 adjacent uncovered spikes. Pollen may now be brought 

 from the variety chosen for the male parent and depos- 

 ited upon the stigmas of the emasculated flowers. The 

 cross-pollinated spike is again covered, and requires no 

 further attention until ripe. 



197. Types of Wheat. — To familiarize the stu- 

 dent with species and subspecies of wheat, give each a couple of spikes and stems 

 of each of the eight species and subspecies, and have him identify by the use of the 

 following outline adapted from Hackel : I 



Triiicum L. Genus. Spikes with rarely aborted spikelets, rachis not articulate 

 in cultivated species ; lowest one to four spikelets smaller than the others, awnless. 



I True Grasses, pp. i8o-i8^ 



In the upper illustration op 

 erator is removine spikelets 

 which are not to becrossed. 

 In the lower the flowers are 

 being opened to remove the 

 anthers (after Hays). 



