290 VEGETABLE FORCING 



primary importance to cross-pollinate any of the six varieties of 

 forcing tomatoes used in these experiments, although it does no 

 harm and may be a slight advantage in some cases. 



"2. When pollen falls upon one side of the stigma only, a one-sided 

 tomato always results. The larger the stigma the greater the ir- 

 regularity. 



"3. The amount of pollen applied to the stigma determines, to a 

 great extent, the size and smoothness of the tomato ; but after apply- 

 ing a certain amount of pollen no further increase in size or weight 

 results by applying more. The small irregular tomatoes grown under 

 glass are caused largely by insufficient pollination. 



"Similar results, as regards the effect of insufficient pollination, 

 were obtained by Bailey and Munson ; and the conclusion that cross- 

 pollination is not essential is supported by Troop, who found that 

 Success tomato, when grown under glass, matured practically as 

 many and as large tomatoes from self-pollination as from cross- 

 pollination with Stone and Combination." 



In the culture of tomatoes at midwinter, it is believed 

 that light yields are due more to imperfect pollination 

 than to any other factor. After March 15, when there 

 is more sunshine and temperatures are higher and ven- 

 tilation freer, the atmospheric conditions are more favor- 

 able for a full setting of fruit. 



When tomatoes are grown out of doors, there is no 

 need of artificial pollination. In the greenhouse, condi- 

 tions are quite different and some assistance is needed, 

 especially during the winter months. 



The best results in hand pollination are obtained if the 

 work is done when the sun is shining and the air of the 

 house is as dry as possible. Ordinarily, from 10 to 12 

 o'clock in the morning is the best time of the day. Care 

 should be exercised that the plants be as dry as possible 

 at this time and also that the humidity be low. 



Pollen is not discharged from the anthers, nor are the 

 stigmas receptive to pollination until the flowers are well 

 developed, a condition shown by the fully expanded 

 petals. 



Various methods of artificial pollination are employed 



