SOUTTIVVORTH : AlFALFA H^■^RI1)1ZATI()I 



440 



effected have been known for many 

 years. A. P. deCandolle described them 

 in 1832; since then the subject has been 

 investigated by F. Hildcbrand, I. Urban, 

 Hermann Miiller, Sir John Lubbock, I. 

 H. Burkhill, C. V. Piper and others. 

 There is such a want of harmony in the 

 pubHshed results of these investigations, 

 however, that local conditions seem to 

 play an important part in them. Hence 

 each worker must find out what ac- 

 tually takes place under his own 

 environmental conditions, if he expects 

 to achieve success in alfalfa breeding. 



To this end experiments were com- 

 menced in 1911 at Ontario Agricultural 

 College, and are still in progress. Their 

 aim is the practical one of breeding 

 better strains of alfalfa, rather than the 

 elucidation of any points of merely 

 theoretical interest. 



Preliminary experiments were ar- 

 ranged to obtain info]"mation on the 

 following points : 



(1). When alfalfa is in flower what 

 effect, if any, has the exclusion of bees 

 and other insects on seed production? 



(2). If alfalfa flowers be self -pol- 

 linated by hand and insects excluded 

 are they sterile or fertile ? 



(3). If it is the case that insects are 

 essential to ensure fertilization, what 

 species appear to be most successful in 

 performing this operation? 



POLLINATION BY INSECTS. 



The answer to the first question con- 

 cerning the exclusion of bees or other 

 insects was of a most decisive character. 

 The results showed that in not one case 

 was a single seed produced when bees 

 were prevented from gaining access to 

 the flowers. Tests were continued 

 throughout a second season with the 

 same resiilts; hence we feel confident in 

 concluding that, in the climatic and 

 environmental conditions under which 

 the tests were conducted, alfalfa flowers 

 are incapable of becoming fertilized 

 when insects are prevented gaining 

 access to the flowers. 



With reference to the second question 

 it was found that though alfalfa flowers 

 are protected from the visits of insects, 

 yet if they be self -fertilized by hand a 

 fair percentage of the blossoms produce 



seed: thus proving that the plants are 

 not self-sterile. 



As regards the third question the 

 answer is less simple. 



No attempt was made to record all 

 the species of insects which visited the 

 flowers. Various butterflies are very 

 commonly found but apparently they 

 are of no value whatsoever in bringing 

 about fertilization of the flowers. After 

 extended observations it was concluded 

 that the common honey bees are the 

 most numerous visitants, but much to 

 oiir surprise it was foimd they have the 

 power to extract the nectar from the 

 flower without liberating the stamens 

 and pistil from the keel. The flower is 

 left intact; consequently no fertilization 

 takes place. In the course of observa- 

 tions extending over three seasons only 

 one case has been seen where a honey 

 bee liberated the stamens from the keel 

 of an alfalfa flower and in this particular 

 instance the bee was enclosed in a cage 

 containing the flower. 



The bumble bee is fairly active in 

 fertilizing the flowers; a species of 

 Andrena is apparently very useful, too. 

 But a variety of wild bee belonging to 

 the Megachile group was found to be 

 much more effective than all other 

 insects combined. This bee goes to 

 work as if it enjoyed the task, and as it 

 will pollinate from eight to twelve 

 flowers a minute it will be readily seen 

 that a single bee may \asit several 

 thousands of flowers per day. 



From the results of our observations 

 and tests we may conclude : 



(1). From the structure and mech- 

 anism of the alfalfa flower it is incapable 

 of self-fertilization if it is not interfered 

 with by external agencies, natural or 

 artificial. 



If however, the stamens and pistil be 

 liberated by suitable artificial means 

 the flower is capable of producing seeds ; 

 hence it is not self -sterile. 



(2). In nature certain wild bees are 

 most effective in liberating the stamens 

 and pistil, hence when there is scarcity 

 of these bees a very small percentage of 

 flowers are pollinated, the result being 

 a great dearth in the production of seed. 



Reasoning from the above observa- 

 tions and experiments we venture to 

 suggest that the shy seeding of alfalfa 



