HYBRIDISATION IN THE UNITED STATES. PA i | 
triflora) have become widespread and popular within the last thirty 
years; and now a new race of hybrids between these and the natives is 
appearing. Thirty undoubted Plum hybrids have been studied and 
tabulated by Waugh, and as many as seven species are represented 
in them. 
A somewhat parallel evolution is taking place in Apples. The Prairie 
States Crab (Pyrus Ioensis) has hybridised with the common Apple, 
producing a race which has been described as a species. These hybrids 
promise something for the mid-continental region. But perhaps the 
largest crossing experiments ever made in North America is in the 
amalgamation of various races and varieties of Pyrws Malus, in the hope 
of securing adaptable varieties for the western Mississippi valley and the 
cold North. The Russian races and the Siberian Crab (the latter, Pyrws 
baccata) are some of the stocks which have been used. Budd long ago 
began this crossing work, and some of the seedlings are now bearing at 
the Iowa Agricultural College. To give an idea of how extensively this 
work is prosecuted, I may say that Craig made over 5,000 Apple crosses 
in Iowa in 1899. For one thing a man was sent to Arkansas, a distance 
of 500 miles, to collect pollen of given local varieties, and this was used 
on the Iowa flowers. This work is systematised between the Iowa 
Experiment Station and the fruit growers of the State. 
The European Pear does not thrive in our Southern States. But a 
new race has made Pear growing profitable there. This race is the product 
of several hybridisations of Pyrus communis and Pyrus Sinensis. Of 
this race two varieties, the ‘ Kieffer’ and ‘Le Conte,’ are widely planted. 
The acres upon which they are planted are counted by the tens of thou- 
sands. The ‘ Kieffer’is now the leader. It is a poor Pear in quality, but 
it is immensely productive, handsome, and a long keeper, and it sells 
well in the open market. This mongrel race has made Pear growing 
possible over an immense region. It must rank as one of the great 
hybrids of the world. 
Our large Orange interests are on a European foundation. But the 
trees are not sufficiently hardy. For the improvement of the Orange in 
hardiness very significant experiments have been begun by Webber and 
Swingle, of the National Department of Agriculture, in amalgamating 
Citrus aurantium and Citrus trifoliata. The results are promising ; 
and it will not be a surprise if the next great advancement in fruit- 
breeding is made in this direction. 
There are important hybrid races in Raspberries and Blackberries, and 
in several other fruits. 
The establishment of the experiment stations twelve years ago gave 
an impetus to the study of plant-breeding problems. The number of 
experiments is very large, when considered in the aggregate, but it is yet 
too soon for measurable results. Some of the efforts in plant-breeding, 
in which crossing is playing an important part, are those on the Apple 
by Craig in Iowa; on the Plum by Waugh in Vermont; on the Orange 
and Pineapple by Webber and Swingle; on Maize in Illinois and Kansas, 
and elsewhere ; on Cotton in Georgia and Alabama; on Strawberries at 
the New York State Station and elsewhere ; on Wheat in Kansas, Min- 
nesota, and elsewhere ; on cucurbitaceous plants at Cornell; on many 
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