SEED INSPECTION 101 



VARIETY VARIATION STUDIES WITH SEED CORN 



Conducted in Cooperation with the Department of Agronomy, 

 William G. Colby, Research Professor 



Studies begun in 1939 to determine the range of variation between lots of seed 

 corn sold under the same or similar varietal name but originating from different 

 seed sources were continued in 1940. One hundred twenty-three samples of seed 

 were collected and grown in a field test plot. The test was carried on in much 

 the same manner as described in Control Series Bulletin No. 102 published in 

 December, 1939, with the exception that the planting date at Amherst was 

 May 20, four days earlier than in 1939. 



The growing season in 1940 was much less favorable for the growth and devel- 

 opment of corn than it was in 1939. Whereas in 1939 practically all varieties 

 tested reached maturity; in 1940, only half the number tested reached that stage 

 of growth and of those sixty-one varieties which did mature, only twenty-five 

 produced sound, well-developed ears before the leaves showed considerable injur}* 

 from frost. Wide variation in performance was found this year as well as last 

 between lots of the same or similar varietal names but from different sources, 

 with respect to the height of plants and to the number of days required for 

 ripening. For example, one lot of Longfellow Flint matured four weeks earlier 

 than another lot, and the earliest strain of Canada Flint matured ten days earlier 

 than the latest. In fact, it is doubtful whether any of the strains of Canada 

 Flint grown represented what is generally considered to be true Canada Flint 

 corn. They all made larger stalk growth, grew longer ears, and matured much 

 later than true Canada Flint. In 1939 all strains of West Branch Sweepstakes 

 and all but one strain of Improved Learning reached full maturity, while in 1940 

 only two out of eighteen strains of the former and not one of the sixteen strains 

 of the latter reached this stage. 



The results of the past two years of testing justify the following conclusions: 



1. The variety name on a commercial lot of open pollinated seed corn is of 

 little value in predicting the performance of that strain with respect to the length 

 of growing season required for maturity. Unless a grower is familiar with the 

 performance of a particular dealer's strain under his local growing conditions, 

 he is likely to lie disappointed with the results from the use of commercial seed 

 corn. 



2. In selecting a variety for grain in Massachusetts, a relatively early maturity 

 variety must be chosen which, though not producing maximum yields of either 

 grain or stover in favorable seasons, can be relied upon to produce good yields 

 of grain and fair yields of stover during unfavorable seasons. Later maturing 

 varieties, which will give higher yields of grain and particularly of stover in 

 favorable seasons, can be used only for silage or as forage in unfavorable seasons. 



In the following table showing results of field tests the laboratory number to 

 which the letter "F" has been added indicates that the samples were taken from 

 seedmen's stock by a State Inspector and were tested for viability in the Seed 

 Laboratory. The source of the seed and results of laboratory tests are given 

 on pages 16 to 25. 



