INHERITANCE OF SEX IN VITIS ROTUNDIFOLIA 
FIRST REPORT 
I 
By L. R. Detjen, Assistant Horticulturist. 
I. Introduction 
All commercial varieties of rotundifolia grapes of the present day 
are self-sterile. Because of this fact, staminate vines are required in 
the vineyards, especially true -of large commercial vineyards, in order 
to produce profitable crops. Just what proportion of the vines should 
be staminate in order to insure maximum crops is at present an open 
question. As recommended by Reimer and Detjen (1)* one staminate 
vine should be planted for every eight fruit-bearing vines. This means 
that one vine out of every nine in the vineyard will bear no fruit, or, in 
other words, eleven and one-tenth per cent (11.1%) of the vineyard 
will be unproductive as far as fruit production is concerned. By plant¬ 
ing staminate vines in the vineyard, land which is capable of producing 
fruit is given over to the production of pollen alone. Indispensable as 
pollen is, it is not the ultimate object of the fruit grower, and hence 
that land which is occupied by the staminate vines represents a direct 
loss. 
By replacing each staminate vine with one which bears both pollen 
and fruit on the same vine, not only would pollen for cross-pollina¬ 
tion be produced, but also a crop of fruit. Hence, if every ninth vine 
in the vineyard could thus be suddenly transformed from an indirect 
to a direct producer, the proceeds of the land might be increased eleven 
and one-tenth per cent. 
If it were possible to replace all of our fruit-bearing varieties with 
self-fertile vines, ideal conditions respective to pollination would pre¬ 
vail in the vineyard. Each pistil in the flower would be surrounded by 
an abundance of pollen, and pollination itself would become independent 
of insect activities. Hence the crops of fruit would become more regu¬ 
lar, irrespective of seasonal and climatic conditions, and the financial 
returns might be increased correspondingly. 
*Reference to cited literature is made by number. 
