ANNUAL REPORT, 1944-45 11 



Potato Seed Treatments. (C. V. Kightlinger and H. M. Yegian.) Experimental 

 work begun in 1943 was continued in 1944, to ascertain further the comparative 

 tolerance of varieties of potatoes grown commonly in Massachusetts to com- 

 monly used disinfecting seed treatments, and also the effectiveness of these seed 

 treatments in controlling rhizoctoniose and scab. The varieties grown were 

 Chippewa, Katahdin, Sebago, Earlaine, Irish Cobbler, and Green Mountain. 

 The seed treatments used were mercuric chloride plus acid, yellow oxide of mer- 

 cury, Semesan Bel, Sanoseed, Wettable Spergon, Thiosan, and Fermate. At the 

 time of treatment, the seed potatoes were sprouted only slightly. 



The inorganic treatments caused little injury to Irish Cobbler and Green 

 Mountain tubers; moderate injury to Katahdin, Sebago, and Earlaine; and rather 

 severe injury to Chippewa. These treatments caused reduction in stands of 

 potatoes in the field, ranging from slight in the case of Irish Cobbler and Green 

 Mountain to rather heavy in the case of Katahdin, Earlaine, and Sebago and 

 heavy in case of Chippewa. 



The organic seed treatments had no noticeable injurious effects on the tubers 

 of any of the varieties before planting; but Semesan Bel, Sanoseed, and Thiosan 

 had some detrimental effects on the stands of the Katahdin and Earlaine vari- 

 eties and worse effect on the stand of the Chippewa, in the field. 



None of the seed treatments seemed to increase the vigor of the plants. Care- 

 ful examination of growing plants and later inspection of mature tubers after 

 digging showed no consistent difference in the amounts of rhizoctoniose that 

 developed from the use of any of the seed, treated or untreated. No scab de- 

 veloped by which to judge the effectiveness of the seed treatments as control 

 measures for this disease. 



On the basis of experimental results obtained from two years of testing, it 

 seems that disinfecting seed treatments are of doubtful value as control meas- 

 ures for rhizoctoniose of potatoes at least. Rather heavy reduction in yields of 

 potatoes of the newer varieties occurred, which it seems reasonable to attribute 

 to the poor stands caused by the detrimental effects of some of the treatments 

 on the seed tubers. On the basis of these facts, it seems doubtful whether dis- 

 infecting seed treatments are advisable for potatoes, especially for the newer 

 varieties used in these tests. 



Potato Variety Trials. (Karol J. Kucinski, Ralph W. Donaldson, Walter S' 

 Eisenmenger.) Because of the favorable growing season last year, all of the 

 potato varieties tested did well, with yields per acre ranging from 510 bushels 

 for Sebago to 347 bushels for Russet Rural. 



Based on yields of marketable size, the ranking of potato varieties in the Ex- 

 periment Station plots during the season of 1944 was Sebago, Pontiac, Sequoia, 

 Chippewa, Green Mountain, Warba, Mohawk, Katahdin, Houma, Irish Cobbler, 

 and Russet Rural. 



Corn Improvement Program. (Hrant M. Yegian.) Fifty-five single crosses 

 were made in the early-maturing group, involving all possible combinations of 

 eleven inbred strains. Thirty-six double crosses were also made from the more 

 promising of the previous j'ear's ninety-one single crosses. Ninety-two varieties, 

 mostly hybrids, were tested for their general adaptability and yield. The results 

 were published in mimeographed form with the cooperation of the Extension 

 Service, and are available upon request. 



Onion Breeding. (Hrant M. Yegian.) Lots of 100 seeds from crosses between 

 Allium fistulosium and A. cepa were soaked at room temperature in 0.1 percent 

 colchicine solution from K to 120 hours to induce tetraploids. The majority 

 of the seeds soaked from 3 to 5 days had thickened cotyledons and primary roots 



