Pollination in Orchards. 375 



sufficient data is collected these charts may be published. They 

 will indicate in a general way which of our standard commercial 

 varieties may be expected to bloom together ; yet each fruit-grower 

 should be prepared to make minor corrections for his own farm. 

 Until more definite knowledge is available, each orchardist should 

 learn how varieties bloom in his own neighborhood before planting 

 them for cross-pollination. It is better, but not always necessary, 

 that the two should bloom exactly together ; if they overlap two or 

 three days that is often enough. 



It is sometimes desirable to plant varieties of different botanical 

 species together for cross-pollination, but this will often be imprac- 

 ticable because of the difference in their blooming seasons. Thus 

 the Oriental pears, as Kieffer, and the European pears, as Bartlett, 

 usually do not blossom together. Kieffer generally blooms several 

 days before Bartlett, hence it is necessary to pollinate it with a 

 variety of its own class, as LeConte or Garber. In some places, 

 however, the two groups blossom approximately together, and then 

 varieties like Bartlett and Seckel should be used in preference to 

 LeConte or Garber, since their fruit has a greater market value and 

 the trees are less likely to blight. Whenever the European pears 

 are used as pollinizers for Kieffer it would be well, if otherwise 

 practicable, to work them on quince roots. Standard Kieffers will 

 often bloom two or three years before standard Bartletts planted at 

 the same time, and unless early blooming dwarfs are intermingled 

 they may be unproductive these first few years. 



The three classes of commercial plums — Japanese, domestica 

 and native — will usually bloom at different periods in the order 

 named ; but when a " spell " of warm weather succeeds a cold and 

 backward spring, varieties of all these groups will come on nearly 

 together and cross-pollination will result. In some places the bloom- 

 ing seasons of these groups overlap so that some varieties of each 

 might be used I'egularly for cross-pollination. 



The Mutual Affinity of Yarieties. 



Another point to be looked after when selecting a pollinizer for 

 Kieffer, or for any other self-sterile variety, is the mutual affinity of 

 the two. That is, will the pollen of the pollinizer fertilize the pis- 



