70 



BREEDING CROP PLANTS 



A common practice used at Minnesota University Farm is to 

 emasculate a number of spikes one day and make the crosses from 

 one to four days later at about the time when the flowers open. 



FIG. 14. Details of wheat inflorescence. 



Upper left, normal spikes ; lower right, emasculated spike; 2, spikelet natural size ; / and g, 

 flowerless glumes; k and r, florets; 3, a single flower closed just after flowering, 3n; 4A, 

 longitudinal diagram before flowering, x 2.5n, a = anthers, o = ovary, s = stigma, / = filament ; 

 4B = diagram after flowering ; o = transverse floral diagram, Qn, fg = lemma, p = palea, a = an- 

 thers, s = stigma; 6, flowerless glume, 7, lemma, 8, palea, slightly reduced; 9, lodicule, 4n; 10, 

 cross-section anther, 26n; 11, pollen grains; 12, ovary and stigma just prior to flowering; 13, 

 at flowering; and 14, shortly after; 15, 16, 17, the mature seed. (After Babcock and Clausen, 

 1918, after Hays and oa.) 



