16 
PACIFIC SCIENCE, Vol. V, January, 1951 
TABLE 5 
The Genotype of Cayenne with Respect to Certain Characters 
CAYENNE 
CONTRASTING 
CAYENNE 
CAYENNE DOMINANCE 
CHARACTER 
CHARACTER 
GENOTYPE 
RELATION 
Spiny tip leaves 
Spiny leaves 
Ss 
dominant 
Spiny tip leaves 
piping leaves 
PP 
recessive 
Anthocyanin in leaves 
no anthocyanin 
Aa 
intermediate 
Yellow flesh 
white flesh 
Yy 
intermediate 
Purple petals 
white petals 
WW 
dominant 
Chlorophyll 
no chlorophyll 
Cc 
dominant 
Normal fruit 
proliferation 
* 
recessive 
Seedless 
seedy 
* 
recessive 
Long leaves 
short leaves 
* 
dominant 
*Undetermined. 
fertile mutation. In this form, the self- 
incompatibility characteristic of Cayenne is 
replaced by self-fertility as a result of a domi- 
nant mutation, but in all other respects the 
variety characters remain unchanged. 
Inbreeding can now be carried out in the 
variety by using these self-fertile mutants. 
Inbreeding is a potent tool for dragging re- 
cessive skeletons out of hereditary closets and 
displaying them in the light of day for all to 
see. By the use of this tool we have pried out 
of Cayenne recessive secrets which it has long 
carried buried within its genotype. 
About one fourth of the inbred progeny 
are semi-lethal and die in an early seedling 
stage. Another fourth are so weak that they 
grow very slowly and reach fruiting maturity 
long after the parent Cayenne. Most of the 
inbreds are low in vigor, with only a few ap- 
proaching that of the Cayenne variety. They 
exhibit a wide variation in fruit and plant 
types, including many fruit and crown fascia- 
tions. The inbred population supplies evi- 
dence that Cayenne is not only heterozygous 
for many recessive and some dominant char- 
acters, but that it exhibits heterosis or hybrid 
vigor. 
A number of variations which had appeared 
in the variety as somatic mutations also ap- 
pear in the inbred population in numbers in- 
dicating Mendelian segregation in a hetero- 
zygous genotype. 
The general characteristics of the inbred 
populations supply some evidence regarding 
the parentage of Cayenne itself. The origin of 
this variety as a hybrid between any of the 
known species of Ananas can be ruled out, 
we believe. The parent or parents producing 
this variety through sexual reproduction must 
be considered at present as unknown varieties 
of A. comosus, or of such a variety of A. 
comosus and a species of pineapple not known 
at the present time. 
SUMMARY 
The Cayenne variety of pineapple was first 
mentioned in an English horticultural journal 
in 1841. Evidence is presented to show that 
it came from French Guiana in 1820. It is 
presumed to have been grown by the Maipure 
Indians in the upper Orinoco River valley 
long before it reached French Guiana. The 
manner and time of its origin are obscure. 
After its introduction into France and Eng- 
land, it became established in many tropical 
countries during the 100 years between 1840 
and 1940. 
The genotype of the variety is highly 
heterozygous and it exhibits hybrid vigor in 
its growth. The variety is self-incompatible 
and must be propagated vegetatively. During 
its long period of vegetative propagation a 
number of somatic mutations have appeared, 
including one giving the mutant type self- 
compatibility. The present Cayenne is a mis- 
cellaneous collection of clones. The diploid 
chromosome number is 50, with 100-chro- 
