TOMATO 289 



the house is properly heated, the pollen grains will germi- 

 nate, and each produce a slender, threadlike tube that 

 will pass down through the style to an ovule, and each 

 ovule thus fertilized will develop into a seed. 



If pollination does not occur, the flower withers and 

 drops off. When only a few pollen grains germinate, the 

 fruit is likely to be small, rough and lopsided. In other 

 words, thorough pollination is essential to satisfactory 

 crops. Numerous experiments and observations have 

 been made to determine the effect of cross pollination 

 and the influence of various degrees of pollination. 

 Some of the most exhaustive studies were made by 

 Fletcher and Gregg at the Michigan Experiment Station, 

 who report as follows in Special Bulletin 39 : 



SUMMARY OF EXPERIMENTS 



"1. The six varieties under experiment were Ignotum, Stirling 

 Castle, Earliana, Best-of-All, Lorillard and Frogmore. The blos- 

 soms on four plants of each variety were self-pollinated, and the 

 blossoms of eight plants of each variety were cross-pollinated with 

 two other varieties. All set fruit equally well. The 265 fruits pro- 

 duced from self-pollination on all six varieties had an average 

 weight of 7-7.3 grams. The 534 fruits produced from cross-pollina- 

 tion on all six varieties had an average weight of 79.1 grams. 



"2. Four plants of each variety were used in an experiment to 

 determine the effect of using varying amounts of pollen. All the 

 flowers on one plant of each variety were emasculated and pollinated 

 on one side of the stigma only. These invariably produced lop- 

 sided and small fruits. All the flowers of one plant of each variety 

 were pollinated with from one to five pollen grains. These produced 

 very small, solid fruits, with an average weight of but 34 grams and 

 having no seeds, or but one or two. All of the flowers on one 

 plant of each variety were pollinated with a large amount of pollen, 

 spread all over the stigma. These produced fruits that were 

 smoother and that averaged 12 grams heavier than fruits produced 

 from flowers that had but a small amount of pollen applied all over 

 the stigma. 



CONCLUSIONS 

 "1. The results of .the investigation indicate that it is not of 



