Mr Compton, Preliminary Note on the Inheritance, etc. 7 
Preliminary Note on the Inheritance of Self-sterility in Reseda 
odorata. By R. H. Compton, M.A., Gonville and Caius College. 
[Read 28 October 1912.] 
AMONG the numerous examples of self-sterility recorded for 
plants and animals the Mignonette is exceptional in that, as was 
discovered by Charles Darwin, certain individuals are completely 
self-sterile, others completely self-fertile. Clearly this affords a 
favourable opportunity for breeding experiments with the object 
of studying the inheritance of these obscure and puzzling pheno- 
mena. Each flower is normally self-pollinated, so that it is only 
necessary to exclude insects in order to ascertain whether a plant 
is self-fertile or self-sterile. Further the anthers are freely exposed 
before dehiscence, so that, although the flowers are small, emascula- 
tion is easy. 
Seed was obtained from various tradesmen, and among the 
plants grown from it both classes of individuals were abundant. 
Experiments are in progress, and the results of the first generation 
may be described with the tentative hypothesis to which they 
oint. ; 
This hypothesis is that self-fertility is a simple Mendelian 
dominant character. In support of it may be mentioned the 
following facts: 
(1) Self-sterile plants when bred inter se throw self-sterile 
offsprmg only. This is in accordance with the view that self- 
sterility is a Mendelian recessive. 
(2) Certain self-fertile plants when self-fertilised yield self- 
fertile offspring only: when crossed with self-sterile plants the 
same result is obtained. These are regarded as homozygous for 
self-fertility. 
(3) Other self-fertile plants when self-fertilised yield approxi- 
mately three self-fertile to one self-sterile offspring: when crossed 
with self-sterile plants about half the progeny are self-fertile, half 
self-sterile. These are regarded as heterozygotes. 
The publication of the data in full is deferred until the com- 
pletion of the experiments, as is also discussion with reference to 
the literature. 
Other characters are also being studied. As regards stature it 
appears that pure-breeding tall and dwarf races exist, and that the 
fF’, between them is intermediate in height. 
An interesting pollen-character also seems to behave in a 
_ Mendelian fashion. Orange-red colour of pollen appears to be 
a simple dominant to bright yellow: self-fertilised heterozygotes 
throw about three reds to one yellow. 
