468 REPORT OF THE CONFERENCE ON GENETICS. 
THE CROSS-BREEDING AND HYBRIDISATION OF PEAS 
AND OF HARDY FRUITS. 
By W. Laxton, F.R.H.S. 
THE object of cross-breeding, from a practical and commercial point of 
view, may be described as an effort to eliminate the bad, and intensify 
the good characters of a plant. With this object in view we naturally 
select as parents two plants bearing, in a greater degree than their 
neighbours, the features we wish to intensify. Having made the crosses 
and got our seedlings up, we expect to find some bearing the desired 
characters in an improved form, but in actual practice we are often 
ereatly disappointed, and feel inclined to throw them all away. We 
have, however, been taught by Mendel to be patient, and not to expect 
too much in the first generation; if Mendel has only done this he has 
done more good than one at first realises, for he has saved from de- 
struction many latent improvements of future generations, and encouraged 
the cross-breeder to proceed with his work instead of abandoning it in 
disappointment and disgust. But we must not expect too much from 
Mendelism. The progress of improvement in annuals suchas the pea will 
show us that real improvements are slow, and the combining of particular 
characters in one plant takes many years of careful work, even with a 
knowledge of Mendel’s theories. The late Thomas Laxton, who may be 
said to be the follower of Knight and McLean in the cross-breeding of 
Pisum, devoted many years to working on the pea, and his principal breaks 
which stand after all these years are not many in number. His work 
was not conducted in the dark, as he knew long before others that 
the pea was a self-fertilising flower, requiring to be emasculated in the 
early bud state, and that breaks were not to be expected in the first 
generation, although he had not worked out any law as to the ratio in the 
second and third generations, as Mendel has done. Great as are the 
benefits arising from the knowledge of Mendel’s law, we find that we 
cannot arrive at any desired result without much labour and patience, and 
still something must be left to chance in the combining of many desirable 
characters in one plant, and great quantities of crosses will have to be — 
made before we attain the end. Mr. Bateson, Mr. Punnett, Mr. Hurst, and 
others have worked on most careful lines, and can tell us how many 
generations will have to be raised if we desire to combine, say, five or six 
characters which are known to be either dominant or recessive, in any 
particular plant. 
In hardy fruits, such as the apple, pear, plum, or strawberry, we have 
been working with impure strains, and have had to trust to chance com- 
binations of desirable characters, hoping by crossing from our best cross- | 
bred seedlings to get the greatest number of breaks. Unfortunately, 
many of these are combinations of three or four characters with an 
important one missing, ‘These constitute faclwres, as in a commercially 
ps eh te eS ee 
