the two-year period, all I did
was turn over some Colchicine to Mr. Best. Mr. Best took the material,
treated the trees and performed as well as any graduate student I had
ever graduated in the 13 years that I was in university work. It is
through his fine cooperation that we are able to start this project, and
I look forward to this developing into a rather important nut breeding
venture. But as you all know, it will take a long time. I have this
paper written. It's only four pages double-spaced.

Colchicine for Nut Improvement Programs

O. J. EIGSTI and R. B. BEST, _Normal, Illinois, and Eldred, Illinois_

Colchicine (1, 2) as a plant breeders' tool is universally well known.
Only limited use has been made of this technique for nut improvement.
Early work was started by Dr. J. W. McKay, a member of the N.N.G.A., but
numerous other problems demanded his attention and the Colchicine
project was not carried to final completion. Other reports are at hand
from Sweden and Japan but these results do not shed direct light on the
problems under discussion today at Rockport, Indiana.

Colchicine, acting on cell-division, ultimately causes a doubling of the
number of chromosomes within those cells in contact with the substance
at the time of division. Such changes are transferred to succeeding
generations by the hereditary chain familiar to plant breeders. Several
species of nuts are among this class of plants with doubled chromosomal
numbers, however, such duplications occurred in nature. A report on this
phase was given at a recent meeting of the N.N.G.A. Therefore such
excellent nut producing species as the pecan are naturally doubled
types, called polyploids. We find numbers such as 32 representative of a
polyploid situation.

Since colchicine is effective in doubling the chromosome number and that
variations in chromosome number exist among species, the authors planned
a series of experiments to determine the best methods of applying
colchicine toward a nut improvement program. Seedlings of pecan were
available and out of this experience a schedule is submitted that may be
of use for other members of this association confronted with particular
problems applicable to colchicine techniques.

The most satisfactory schedule for doubling the number of chromosomes is
given in a number of steps as listed below.

1) Select expanding vegetative buds in the earliest stages of
development.

2) Use seedlings or branche