PYRUS BACCATA AS A STOCK FOE THE APPLE. 1 63 



years is needed to change a plant so as to enable it to en- 

 dure a greater degree of cold. This explains why in my plant- 

 breeding operations I insisted on breeding for hardiness and 

 why it is desirable to work with native species whenever pos- 

 sible. The Russian race have hardiness to start with at the far 

 north. In regions where the so-called American apples are hardy, 

 there is no need for them with a few well known exceptions. 

 When visiting Russia in 1894 and 1897 I learned that the Rus- 

 sians had discovered another fact, that the root of their hardiest 

 race of apples was more tender than the top in their provinces 

 where severe cold often comes with the ground bare. They had 

 found that none of their common apple seedlings would endure 

 the test. They had solved the problem by seeking a race of 

 apples much hardier naturally, the pure Siberian crab ( Pyrus 

 baccata), which will endure sixty below zero Fahrenheit. The 

 effect of this w^as to make the apple top bear at least two years 

 earlier and to dwarf the ultimate size of the tree. These trees 

 were all grafted or budded at the collar under the surface of the 

 ground, so that the entire root-system was of the crab and the 

 entire top of the apple. 



3. This primitive species of the apple, Pyrus baccata, was 

 long ago introduced into the United States, where it has been 

 largely grown in American orchards, and a numerous brood of 

 hybrids has resulted. This hybrid progeny is now considered by 

 Prof. L. H. Bailey to be the species known as Pyrus prunifolia 

 and is represented by such crabs as Transcendent, Orange, Min- 

 nesota, Whitney and others with persistent calyx segments. 

 The pure Pyrus baccata has deciduous calyx segments and is 

 represented in cultivation by the Red Siberian, Yellow Siberian 

 and Cherry crabs. 



4. The Russians used Pyrus prunifolia crabs also for stocks. 

 At Moscow they were used interchangeably, but Pyrus baccata 

 was spoken of the most, owing to its great hardiness. The Rus- 

 sians were endeavoring to improve their own apples in hardi- 

 ness by crossing with Siberians. Some of these I have en- 

 deavored to import and to produce more by crossing at Brook- 

 ings. Such efforts certainly give more promise than to disregard 

 De Candolle's law in selecting the parents with which to begin 

 plant-breeding operations. 



5. The practice of piece-root grafting was not in favor with 

 the German and Russian propagators whom I talked with con- 

 cerning the matter. Their favorite method was to graft and bud 

 at the collar on seedlings already established one season in the 



