v^^^ 



Phyi^iolofiical Pre-detcrm iiiatmn 



In the case of the peas a further important advantage is gained by 

 the selection of large seed, namely, increased earliness (see Fig. 2). 



Burgerstein (8) has very thoroughly worked out the case for Phaseolns 

 vulgaris, var. ; the followincr table summarises his results: 



Table XV. 



Yipld from Small Seeds compared with the Yield from 

 Large Seeds taken as 100*. 



Relation of average weight 



* The plants produced from the small seeds ripened by the IHth of August, those 

 produced from the large seeds by the 22nd of August. 



From the above table it is seen that the bean plants produced from 

 very small seeds gave rise to seeds which were only slightly smaller 

 than those which under similar conditions were produced by plants 

 from very large seeds. Statistical work by Harris (34, m, & ,38) has since 

 confirmed Burgerstein's results. Harris found that in the case of 

 Phaseolus vidgaris the number of pods and also the number of ovules 

 and seeds per pod were greater in plants produc8d from the larger seeds. 



With many other crops conclusions similar to those of Lehmann 

 have been reached^, for instance, Lyon and Hitchcock (^^S) with alfalfa. 

 Walker (70) with beet, 8hamel(t«) with tobacco, Webber and Boykin(78) 

 with several varieties of cotton, and 8precher(ti.s) with Hevea brasilicnsi.s, 

 but the results recorded by Fruwirth in 1917 are worth recording in more 

 tletail. Fruwirth (22) carried out investigations with lucerne and sainfoin 

 for five years. His work proceeded from the earlier investigations of 

 Wollny(8i), who showed that for a given area and equal numbers of 

 plants heavy seeds of fodder maize and red clover were superior to the 

 light seeds. Fruwirth 's work is excellent in that he eliminated spacing 

 as a factor disturbing the yield results. Three lines of experiment were 

 followed, viz. : 



(i) comparison of single plants; 



' Arthur (1), Zavit/. (84), and Cunimings (12) give data wiiich clearly show a distinct 

 advantage in the use of large and heavy seed in the case of several different classes of farm 

 crops. 



