Some of the earlier equipment employed by Garner and Allard, who used many kinds 

 of wild and cultivated plants. 



Photoperiod an Aid in Plant Breeding 



The photoperiodic behavior of many varieties <>i plants is of great 

 economic significance in the developmenl of new varieties. In many 

 localities the common potato as grown in the field frequently produ 

 large numbers of flowers bul lew seeds. In the commercial produc- 

 tion of potatoes this is no detrimenl because they are grown bj 

 planting whole tubers or pieces of them. But if a new variety of 

 potato is desired, il is mosl quickly obtained by growing the seeds 

 and selecting the type desired from among the seedlings. Seeds 

 are now readilj obtained l>\ growing potato plants in greenhouses, 

 where the photoperiod can be lengthened to suit their requirements 

 for seed development. When this is done and utter pollination has 

 been effected, a number of varieties which usualrj do not set seed 

 well do so \ erj readily. 



