236 
years, Dr. Nilsson-Ehle produces for the Station of Svalov 
new combiiiations of genetic factors, by crossing - experiments 
with a definite aim^ which obviously is a much more certain 
way than the happy-go-lucky selections from mixtures of Svalofs 
earlier days. 
But it is well to remember that Dr. Nilsson-Ehle could 
do his excellent work as well in Madeira or in California as in 
Svalof^ and with quite the sarae results for his countri, if only 
he sent his seeds there to be tested by his agricultural experts. 
For any country^ wishing to produce varieties more sui table 
to different conditions in its diverse parts^ it is quite possible^ as 
well as most economical, to have one single easily accessable 
Station at which an experimental breeder can make a great 
collection of diverse varieties^ and produce new ones for the 
agricultural experts at the different local experiment-stations to 
try and compare. 
I would especially emphasize the need of having a great 
collection of types^ imported from other countries, quite indepen- 
dently from their greater or lesser importance in their own 
country. I am quite certain that in trying only „good" imported 
varieties, one considerably limits one's chances to find a suitable 
one for one's own, probably somewhat different conditions. It is 
obvious that, whenever a choice is made between a great number 
of different biotypes, a great number of them are rejected, which 
would be found excellent if only the exact locality for which 
they would fit could be ascertained. 
The requirements of a variety of wheat are extraordinarily 
different for different localities. In one place the straw has nearly 
the same value as the grain, and a wheat is required, which will 
respond to a dose of artificial fertilizer by a heavy yield of good 
straw, at another place the straw has no value whatever, and the 
same wheat might be far from profitable in favorable years. In 
some localities even the wheat with the weakest straw does not 
lodge and there a variety may be excellent which at other places 
would be hopelessly ruined by heavy rains. 
In arid and semi-arid regions everything depends upon the 
price of the water available for irrigation. Whereever water can 
be had in sufficient quantity, and is not too expensive, it will 
be found, that a rather longlived wheat, capable of producing a 
good yield when irrigated will be required. Where water is 
