Parthenocarpy 227 



time can be a small but real advantage to commercial producers where 

 early yields are financially of the highest value (VV^ittwer et al, 1948). 



Increases in Yield 



There appears to be considerable disagreement in the literature as 

 to whether the use of auxins in setting tomatoes increases yield or 

 not. The problem can be broken down into two parts: the first of these 

 is the effect of auxins on fruit size, and the second is the question of 

 auxin effects on early yield vs total yield. 



At present five reports in the literature indicate that no increases 

 in fruit size were obtained following the use of auxin and eight other 

 reports show distinct gains in fruit size. The cases in which gains were 

 found are all cases in which the auxin was applied locally to the flower 

 cluster and not as an overall j^lant spray. Extensive tests reported by 

 Mann and Minges (1949) show that significant gains in fruit size can 





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Fig. 97. The effects of forcing fruit-set in field tomatoes with auxin (p-chloro- 

 phenoxyacetic acid) upon the harvest pattern of marketable fruit (Mann and 

 Minges, 1949). 



