340 MINNESOTA STATE HORTICULTURAL SOCIETY. 



"The reader will now ask how can plants be bred more resistant 

 to cold. This is done by crossing them with hardy species. Many 

 examples might be given of this. In a general way, it may be stated 

 that by crossing hardy wild fruit plants with tender cultivated ones 

 new individuals may be produced combining the hardiness of the 

 wild with the size and quality of fruit of the tame. A good illus- 

 tration of this line of endeavor is the work of Webber and Swingle, 

 of the United States Department of Agriculture, in producing or- 

 anges and lemons more resistant to cold than any now existing. 

 Citrus trifoliata, a very small inferior fruited species from Japan, 

 but hardy as far north as Philadelphia, was crossed with choice large 

 fruited oranges and lemons. The remarkable results already ob- 

 tained indicate that the orange belt will soon be extended far north 

 of the present limits. 



"At the South Dakota Experiment Station an effort is being 

 made to extend the cherry, peach and apricot belt north to the Mani- 

 toba line by similar cross-breeding experiments. The present writ- 

 er regards the plan as entirely feasible, although a series of years 

 will be necessary for completion of the work. In all the fruit- 

 breeding work at the South Dakota Experiment Station perfect 

 hardiness of plant is the first consideration. Any seedling of the 

 apple, crab, plum, cherry, sand cherry, pear, peach, apricot, straw- 

 berry, raspberry, currant, gooseberry, grape or other fruit showing 

 inability to endure the winter without protection of any kind is at 

 once discarded. In breeding hardy roses the same principle is fol- 

 lowed. In the work with vegetables the endeavor is to select for as 

 great a degree of earliness as is consistent with a fair crop." 



Mr. Elliot : Is the native plum you mention like the clingstone 

 or the freestone Wolf? 



Prof. Hansen : It is a freestone, like the original Wolf. 



Mr. Sahler: Which is the best? 



Prof. Hansen : I think that the freestone, which was the original 

 variety sent out as Wolf, is the better of the two. The clingstone 

 Wolf, which has appeared in recent years, is either a bud variation 

 or a nursery mixture. It is certainly an excellent plum, but it 

 originated in the southern border of Iowa, in Wapello county, 

 and I think it appears reasonable to believe that a plum we find 

 native in our northern woods if equal in quality and size and pro- 

 ductiveness will be better adapted to our conditions. I believe that 

 is a safe proposition. Many of our standard varieties of plums are 

 not early enough for the northern part of South Dakota or for North 

 Dakota. The earliest plums on the South Dakota Experiment Sta~ 



