1019] FIELD CROPS. 831 



weight of suckers, and ou the inheritance of height of plants, number of 

 nodes and leaves, flowering, and leaf size and shape. The results may be 

 summarized as follows: 



The branching or suckering habit of tobacco is a distinct characteristic and 

 behaves as other inheritable characters, although subject to very considerable 

 fluctuating variation, due to environmental conditions and to certain physio- 

 logical factors. The Fi generation of the cross mentioned above was inter- 

 mediate between the two parents for number of suckers, but somewhat above 

 the intermediate condition for weight of suckers, thought to be due to the 

 stimulus of heterozygosis. The reciprocal Fi generations behaved in an almost 

 identical manner, and the variation was on the whole no more than that of 

 the most variable parent, as shown by the standard deviation. 



The F2 generation possessed a range of variation as great or greater than 

 that of the combined range of the two parents. The standard deviation from 

 the mean as regards the suckering habit was practically twice that of the 

 average of the parents or of the Fi. The large ma.1ority of the F2 plants 

 appeared to approach more nearly the Cuban type than the Little Dutch type, 

 although the means more nearly resemble the intermediate condition found in 

 the Fi. 



Segregation in regard to the suckering habit was deflnitely shown in the Fs 

 and succeeding generations, strains having been isolated which suckered even 

 less profusely than the Little Dutch parent, while others were almost as pro- 

 lific as the Cuban type, the large majority ranging between the two extremes. 

 The standard deviations indicated that certain of these strains were no more 

 variable than the parents and were probably breeding true for the suckering 

 habit, while other strains carried as far as Fs have failed to show any signs 

 of the homozygous condition. The production of few and small suckers ap- 

 peared to be the recessive condition. The inheritance of the suckering habit 

 is regarded as purely Quantitative and not separable into satisfactory classes 

 or ratios. The results are held to be comparable with those obtained by East, 

 Hayes, and Emerson for various quantitative characters in tobacco, maize, 

 and other plants, and it is believed the data should be interpreted in a similar 

 way on the multiple factor hypothesis. 



It is stated that random observations and systematically recorded data tend 

 to show that no particular correlation exists between number, size, or shape of 

 leaves and the number or size of suckers in the second generation of a cross 

 between a large suckering and a small suckering type. While the prcxluction of 

 a nonsuckering type of tobacco combined with the commercial practice of " top- 

 ping " is regarded as probably impossible for purely physiological reasons, it is 

 believed that by crossing and selection the production of relatively few and 

 small suckerng strains of a certain type of leaf may be obtained. This may 

 be of some commercial importance, although the combination of this character 

 with the proper leaf shape and quality will be extremely difficult to obtain. 



The combination and segregation of characters has also been demonstrated 

 in this cross for such characters as height of plant, number of nodes and leaves, 

 size and shape of leaves, and time of flowering. The occurrence of two abnor- 

 malities entirely foreign to the parents, one a morphological monstrosity and 

 the other a " physiological weakness," are recorded as illustrating the occur- 

 rence of " new " characters in a variety cross under controlled conditions. 



Flue-cured tobacco in Canada, D. D. Digges and H. A. Feeeman {Canada 

 Expt. Forms Bid. 38, 2. sei: {1919), pp. 44, fi<js. 7).^Tliis publication comprises 

 a general discussion of the production, harvesting, curing, and handling of 

 flue-cured tobacco in Ontario by D. D. Digges (pp. 9-30), together with 



