16 



MASS. EXPERIMENT STATION BULLETIN 318 



grades of sets would determine whether to buy those having the lesser or the 

 greater range in size. 



Table 5. Percentage of divided bulbs, bulbs with seed stalks, 

 and grades of onions. 



Grown from Grown from 



Y % - to M-inch 3/8- to 7/8-inch 



sets sets 



Per cent Per cent 



Bulbs divided (by count) 0.34 10.24 



Bulbs having seed stalks (by count) 0.52 4.22 



Bulbs over 1 X 4 inches having no seed stalks . . 97.4 94.7 



Bulbs under IJ4 inches having no seed stalks 2.2 2.9 



Bulbs having seed stalks (by weight) .4 2.4 



No. 1 bulbs*: 



Between \ l i and 1% inches 2 5 



Between 1 % and 2 }£ inches 30 33 



Between 2L4 and 2% inches 58 51 



Over 2% inches 10 11 



*Sound onions without seed stalks were considered as No. 1. 



PRODUCTION OF MORE DESIRABLE ONION SETS 



The experiments just reported, on the influence of size of set on yield and quality 

 of onions, emphasize the lack of accurate information regarding methods of 

 growing desirable sets. The present methods are quite varied and usually meet 

 with only partial success. It was, therefore, felt that this Station could well 

 make some studies of factors thought to be important in the growing of sets. 

 In a preliminary test in 1931 three variables were studied: rate of seeding, rate of 

 fertility, and width of row. Seed was sown at rates of 50, 70, and 90 pounds per 

 acre; grown without any fertilizer and with 500 pounds per acre of a 4-12-8 fertilizer; 

 and with one-inch and two-inch rows. 



The effect of the fertilizer became apparent early, and the fertilized plots looked 

 better than unfertilized plots throughout the season, but the value of the other 

 variables was much less apparent . The onions were pulled 106 days from planting, 

 allowed to dry a few days, clipped, and taken inside where they were carefully 

 graded into four sizes, under J4 inch, \^ to Yi inch, Y2 to % inch and over % 

 inch. The two-inch row produced considerably more sets tljan did the one-inch 

 row, with the greatest increase in the larger sizes. The fertilized plots produced 

 more weight of the most desirable size, Y2 to % inch, although not a greater 

 percentage of the whole, than those not fertilized. The smallest rate of seeding 

 pr< duced the greatesl percentage of sets of the most desirable size. It was clearly 

 shown that a very large number of the sets did not make sufficient growth to 

 reach the most desirable size. Either lighter seeding or greater fertilization would 

 tend to remedy this, but would also increase the number of sets too large for 

 planting. After storage of about six months, the most desirable size was found 

 to have Buffered the least loss from sprouting and decay. Also, the fertilized sets 

 kept slight ly better than those not fertilized. 



