Bowman: Deterioration in Horticultural Varieties 
then, we have evidence of considerable 
reversal to the simple cruciferous 
ancestral forms which were presumably 
purple, and signs of mixed heredity 
in high degree of fertility and the 
variations in the foliage. 
THE CENTAUREA 
In the Centaurea the type was of a 
very deep blue color with at least three 
or more rows of false rays. Reversal 
was seen in over fifty percent of the 
plants in the population of this sowing, 
as the heads had only one, or at the 
most, two rows of false rays and an 
increase of functional disk florets. In 
color also there was evidence of con- 
tamination of the strain. Beside the 
deep blue of the type there were all 
shades of lighter blue, as well as white, 
pink and maroon, showing that this 
strain had not been carefully selected 
and segregated at the seed-farm. 
CARELESS SELECTION OF SEED-PARENTS 
In all these foregoing examples, it 
may be deducted that many standard 
horticultural varieties have consider- 
ably deviated from their types. In 
these particular cultures the fact that 
the growth conditions were uniform, 
and other factors which would have 
lowered the vitality of the generation, 
such as fungous and bacterial diseases, 
were absent, should be conclusive 
evidence that causes for this deviation 
have been inherently genetic, i.e. that 
the seed was of poor quality and con- 
taminated with other and dominant 
inferior strains, or that there was a 
general lowering, reverting and atavis- 
tic tendency due to unknown physio- 
logical conditions at the breeding 
farms, which has affected the germ- 
plasm of these varieties. 
In regard to careless selection by the 
breeders of the seed-parents having the 
desired characters, or perhaps the 
383 
failure to keep up the nutrition or 
some other cultural condition on the 
farms, or the lack of careful and skilled 
pollination, much, or perhaps all, can 
be attributed to the war—directly due 
to the lack of labor on the seed-farms; 
but in all events this deterioration in 
stock has occurred and it may be several 
years until these strains are again 
recovered or are replaced by new ones. 
WHAT THESE OBSERVATIONS INDICATE 
Another and rather interesting fea- 
ture of these observations was the 
recognition of those hereditary factors 
in these particular varieties which are 
least fixed or stable in the constitution 
of these plants. Some of these have 
become conspicuous by their complete 
disappearance or modification. On 
the other hand those characters which 
are dominant and persist to the last 
may only mask or cover those more 
unstable characters which apparently 
have disappeared. 
Of course, from a purely genetical 
point of view, these horticultural 
varieties are far removed from the 
simple strains of known heredity which 
are usually chosen as material for 
genetical investigation and research. 
Most all horticultural varieties are 
sports or the results of very complex 
hybridizations and cross pollinations, 
and if actual inbreeding experiments 
should be carried on with them through 
four, five or more generations for the 
segregation of Mendelian characters, 
all sorts of peculiar results might be 
expected from these much mixed and 
heterozygous strains. 
In conclusion, then, it may be re- 
peated that these observations perhaps 
indicate some of the less firmly fixed 
characters in the heredity of these 
varieties which have undergone a 
deterioration from their standard 
types. 
