294 MINNESOTA STATE HORTICULTURAL SOCIETY. 



to a greater virulence of the disease or to a decreasing vitality of 

 the potato plant. It seems as though the latter were the case. That 

 there is a great difference in varieties in their disease-resistant 

 power has been conclusively proved at the Minnesota Experiment 

 Station, where about fifty varieties are annually tested. During 

 the past summer the percentage of rot varied with the different 

 varieties from one to forty per cent at the time of digging. This 

 tendency towards disease on the part of our cultivated varieties 

 has led the horticultural department of the experiment station to 

 try to originate new varieties having greater disease resisting 

 powers. As a basis for this improvement the Solanum commer- 

 soni, a species of potato from the upland plateaus of South America, 

 was crossed with the Minnesota No. 26 seedling. While this 

 seedling is not as good as our average cultivated variety, yet it was 

 the only one out of fifty varieties grown that produced fertik 

 pollen. In fact, one of the greatest obstacles in crossing the potato 

 is to get varieties that produce fertile pollen, for as soon as the 

 potato is brought under cultivation it has a tendency to throw it's 

 reserve strength into tuber formation instead of developing seed. 

 Although the seed-ball of the potato normally produces a large 

 number of seeds, yet it has been found that the fertilization of one 

 ovule, or seed, was a sufficient stimulus to cause the seed-ball to 

 develop. A few seeds were obtained from this crossing. 



The object in view in cross-pollinating the grape is to originate 

 a grape of good qualify which will still be hardy enough to with- 

 stand our severe winter climate without protection. The principal 

 reason why we cannot profitably grow grapes in this state is be- 

 cause of the cost incidental to winter protection, which our com- 

 petitors in the eastern states do not have. 



The Beta grape was used as the mother plant in this crossing 

 and was pollinated by some of our cultivated varieties, principally 

 the Janesville. The Beta grape is an exceedingly hardy and pro- 

 ductive variety, but the fruit is small, somewhat acid and inferior 

 for eating out of the hand. By crossing it with some of the standard 

 cultivated varieties we hope to produce a grape that will have a 

 hardy vine, like the Beta, and a better quality of fruit. The Beta 

 was used as a mother plant and crossed with the other varieties 

 because it has been found that the mother plant has a tendency to 

 impart the vine characteristics to the progeny while the pollen parent 

 is more likely to influence the quality of the fruit. 



Cross-pollination of the grape is a simple process. When the 

 mother plant is in blossom the clusters to be pollinated are selected. 

 The open flowers and late buds are nipped off. The caps are lifted 



