SEED INSPECTION 65 



Quality of Onion Seed Produced in 



The Connecticut Valley, Season of 



1936 



During the spring months of 1937, twenty-one lots of onion seed produced in 

 the Connecticut Valley were sent to the Seed Laboratory for cleaning and via- 

 bility tests of the graded clean seed. 



The same methods 1 for cleaning were employed as during the spring of 1936 

 when ten lots of seed were received, cleaned and graded, except that hand thresh- 

 ing of the seed gave place to a home-made mill, designed on the principle of a 

 grist mill, but having wooden disks with contact faces of corrugated rubber in 

 place of stones. 



Since the machine used for cleaning employs screens and air blast, only the 

 heaviest seed are cleaned in the first operation. Successive operations with 

 more air on the remaining unclean seed result in several grades of clean seed 

 being obtained from each lot of seed processed. Most lots of seed break down 

 into three grades, but occasionally when the seed is light in weight a fourth 

 grade may be obtained. 



The following table shows the weight of the 21 lots of unclean seed as re- 

 ceived, the total weight of the cleaned seed, and the weight and viability of each 

 grade obtained by repeated machine separations. 



Lots numbered 22, 23, and 24 represent commercial clean seed purchased 

 by one of the local onion growers and loaned to the laboratory for breaking 

 down into grades corresponding to those obtained from the locally produced 

 seed. 



The data recorded in this table show that, in most instances, grades 1 and 2 

 are of very high quality, as judged by viability tests. Grade 3, in most instances, 

 gave a fair test but in no case equal to the two higher grades and with some lots 

 of seed decidedly inferior, so much so as to throw doubt on the wisdom of blend- 

 ing this grade with the others for field use. The three lots of graded commercial 

 seed show differences in viability comparable with grades of locally produced seed. 



One ounce of seed from each grade of ten lots of local seed and a like amount 

 of seed from each grade of the commercial lots was sown in the field for a test 

 upon yield, trueness-to-type, and correlation of viability of the seed with proper 

 spacing in the drill. Late planting and an unfavorable season for culture of seed 

 onions made it impossible to draw reliable conclusions from the poor crop of 

 onions grown. It is planned to repeat this experiment in 1938. 



"See Massachusetts Agricultural Experiment Station, Control Series, Bulletin No. 86, Nov- 

 ember, 1936 — Page 63. 



