11 MASS. EXPERIMENT STATION BULLETIN 318 



at all freely when selfed or when crossed with some other strains; others have 

 kept quite vigorous and grow and produce seed readily. 



Several lots of inbred seed of the Japanese, or set type of onion grown locally, 

 were planted for the development of sets for planting instead of for bulbs for seed 

 production. This phase of onion development was undertaken because the 

 Japanese (or Ebenezer) set is at present the principal type ot onion grown here, 

 and the set method seemed better suited to the development of onions for that 

 purpose than the seed method which had previously been used entirely. This 

 method requires three years per generation instead of two, as is the case with the 

 seed method, but has a number of decided advantages. 



The sets for planting have now been grown from inbred seed three years; sets 

 have been planted for bulb production two years; and one crop of seed has been 

 grown from bulbs produced from sets. Some difficulty has been experienced in 

 getting good sets from small amounts of seed, but on several occasions very good 

 sets have been grown. In growing strains frcm sets, marked differences were seen 

 in seed-stalk and multiple-bulb development, particularly; but also in time of 

 maturity, shape of bulbs, type of skins, and top growth, similar to those observed 

 in seed onions but usually more marked because of the much more advanced 

 stage of growth possible with sets. When the bulbs grown from sets were planted 

 for seed production they did extremely well, partly because of the extra size and 

 strength and partly because a much larger number had developed into good 

 bulbs which gave a better chance for selection. 



Another way of getting good-sized mature bulbs from the inbred and crossed 

 seed was found to be starting the plants in the greenhouse in early February and 

 later transplanting them to the field. This method gave very good results. A 

 much higher germination of seed was obtained in this way and nearly every seed 

 which germinated grew into a fair-sized bulb. These plants were very uniform 

 in type during the growing season and produced a finer lot of bulbs than had 

 ever been grown from seed sown in the field. The substitution of transplants for 

 sets in commercial production appears to have possibilities. Some fairly large 

 bulbs of the Sweet Spanish types, which when grown from seed require a longer 

 growing season than prevails in the Connecticut Valley, have been grown in this 

 way. 



DISEASES OF ONIONS 



The smut disease of onions, caused by the fungus Urocystis cepulae, has long 

 been prevalent in the Connecticut Valley. As work at this Experiment Station 1 

 has sh(,\vn, the disease is controllable by a solution of formaldehyde, 1 gallon 

 diluted to 50 gallons with water. If the soil is dry, this is applied at the rate 

 of 50 gallons per acre. If the soil is medium moist, 62^ gallons per acre should 

 be applied, and for a wet and heavy soil 83 1 3 gallons per acre is indicated. 

 Details of the method of application are discussed in the bulletin mentioned. 



Two of the most common diseases of onions in the Connecticut Valley are 

 downj mil. lew, which is caused by the fungus Peronospora schleideni, and blast. 

 Blast, or the premature death of the foliage, has usually occurred about the 

 third week of July when periods of rain were interrupted or followed by high 

 ten peratures, bright sunlight, and drying winds. The disease is probably not 



'Anderson, P. J., and Osmun. A. Vincent. The smut disea \1 i . \ •> Expt. Sta. 



Bui. 221. 1924. 





