209 



proof in these experiments that newly introduced seed retains at first the char- 

 acter developed in the place where it has been bred. If, for instance, heavy 

 soil reduces the starch content, the reduction does not take place in the first 

 year with new seed and therefore this seed contains more starch than the 

 native seed. On sandy soil, however, a variety has been bred which contained 

 the largest amount of starch possible under the conditions. The newly intro- 

 duced varieties with the peculiarities brought with them, however, had not 

 as yet adjusted themselves sufficiently to these conditions and therefore gave 

 a lesser yield. Exhaustion or degeneration will therefore take place only 

 where a variety does not find the cultural conditions it requires. The cir- 

 cumstances may be similar in all phenomena of supposed exhaustion or 

 degeneration. Our cultural varieties are the products of breeding under 

 very definite conditions of position, soil and weather, and are kept pure only 

 if they again find conditions similar to those where they are grown. If it is 

 desirable to make use of valuable peculiarities of any definite species in 

 another locality, good results are obtained only by frequently renewing with 

 seed from the naHve habitat or from habitats similarly situated. 



Sensitiveness of the Sweet Cherry. 



The complaint in different places that the sweet cherry every year suf- 

 fers increasing injury from frost, the exudation of gum, attacks of fungi 

 etc. is often due to the failure to observe the fact that the cherry does not 

 like a heavy soil. This circumstance has been especially emphasized recently 

 by Ewert^ and deserves to be repeatedly borne in mind by the fruit breeder. 

 Naturally here also some cultural varieties are able to adapt themselves 

 better to heavier soils, but in general the rule holds good that the sweet 

 cherry likes a light, deep soil and flourishes especially well on alluvial sand 

 and loose soils. The amount of nutrition in the soil is a far less decisive 

 factor than its physical constitution, especially its granular condition. 



Often a scarcity of lime is given as the cause of poor growth,- which 

 can be overcome by supplying lime. The improvement in growth, however, 

 may not always be traced back to the nutritive action of the lime but to the 

 change in the physical soil condition due to it, viz., greater friability and 

 thereby increased aeration. Ewert's statements throw light on lime as a nutri- 

 tive substance. He states that the sweet cherry flourishes even when the lime 

 content is from 0.04 to 0.15 per cent. Soil with possibly 80 per cent, of 

 easily washed away particles is not suited to the growth of cherries even 

 with 40 to 45 per cent. CaCOg, if this is chiefly present in so fine a condition 

 that it also can be washed away. The cherr)^ is peculiarly sensitive to stand- 

 ing water and it grows best in dry soil in open places. 



The Tan Disease. 

 Trees standing on damp ground may show decreased growth, especially 

 if their early growth was rapid. The older bark cracks or, after the outer- 



1 Ewert, Das Gedeihen der Siifskirschen auf einigen in Oberschlesien liauflgen 

 Bodenarten. Landw. Jahrb. 1902, Vol. XXXI, p. 129. 



