BUD-MUTATION IN THE POTATO AND ITS AGRICULTURAL SIGNIFICANCE 117 
other plants, very easily overlooked. Owing to the more rigid selection, 
practised in recent years in the Netherlands, strains have been found 
within certain varieties, which differ very considerably from each 
other; probably these have arisen by bud-mutation. Indications have 
been found that susceptibility to leaf-roll and late blight may sudden- 
ly change. For the question of degeneration, further investigation con- 
cerning this point is very desirable. There is no good reason to believe 
that bud-mutation is limited to a few characteristics only. 
In the case of several bud-mutants, reversion has been found. In 
1923, among the „gold margin’’-plants about 10 % produced, in grea- 
ter or less degree, normal „Eigenheimer’”’ leaves; in the case of other 
bud-mutants, reversion was observed to a very slight extent only. Ma- 
ny investigators (even as far back as DARWIN, 1868) sought a connexion 
between the heretozygous nature of the plant and the occurrence 
of bud-mutation. Potato-varieties are generally heterozygous. The 
statement of EAST (22), that bud-mutation always refers to losses of 
- characters, cannot be accepted. Nor does FRUWIRTH (27) in his , Vege- 
tative Spaltungen’’, give a satisfactory explanation. The cases of 
reversion observed can, not be explained in this way, unless bud- 
mutation should be the result of an alteration in some of the exterior 
series of cells. Then a periclinal chimera would arise and from this 
chimera the original plant might again come forth. In such a case, the 
reversion need not be the reverse reaction of the process that caused 
the bud-mutant to come into being. CORRENS (14), BAUR (3) and 
EMERSON (24) mention a gen-mutation in the epidermis only. 
Hence possibly varieties of potatoes may be formed by means of bud- 
mutation that cannot be obtained from seed. In the seedlings of 
„Eigenheimer’’ and „Red Star’’ I have never observed „gold margin”, 
„raspberry leaves”, „green red star’ or , variegated red star”, but 
one may often find among the seedlings such with blue tubers and very 
many bolterlike plants. 
CARRIERE (12) and DARWIN (18) mention that some bud-mutants 
have become widely distributed. In Friesland, the „blue Eigenheimer” 
and , variegated Red Stars” are generally grown. The varieties grown 
at large may consist out of different strains and the selector will have 
to pay attention to all characters that may be of value for cultivation. 
A subdivision of the varieties, based upon a good knowledge of the 
different strains, is of great agricultural importance. 
