Table Of Content/z
PURDUE UNIVERSITY
THIS IS TO CERTIFY THAT THE THESIS PREPARED UNDER MY SUPERVISION
•EMTrrr.im ^6U6 ^os&g6 Effects on ^B.pbohydPati6_______
Content of - "°rn --------------------------------------------
COMPLIES WITH THE UNIVERSITY REGULATIONS ON GRADUATION THESES
AND IS APPROVED BY ME AS FULFILLING THIS PART OF THE REQUIREMENTS
FOR THE DEGREE OF
ijQsto.ii .of-Philosophy
Professor in Charge of Thesis
Heah or School or Department
TO THE LIBRARIANS----
m
THIS THESIS IS NOT TO BE REGARDED AS CONFIDENTIAL.
PBorcrsfioR nr obajiqb
GRAD. SCHOOL FORM 9
GENE DOSAGE EFFECTS ON CARBOHYDRATE
CONTENT OF CORN ENDOSPERM
A Thesis
Submitted to the Faculty
of
Purdue University
by
Gerald Dunn
In Partial Fulfillment of the
Requirements for the Degree
of
Doctor of Philosophy
August, 1951
ProQuest Number: 27714302
All rights reserved
INFORMATION TO ALL USERS
The quality of this reproduction is dependent upon the quality of the copy submitted.
In the unlikely event that the author did not send a complete manuscript
and there are missing pages, these will be noted. Also, if material had to be removed,
a note will indicate the deletion.
uest
ProQuest 27714302
Published by ProQuest LLC (2019). Copyright of the Dissertation is held by the Author.
All rights reserved.
This work is protected against unauthorized copying under Title 17, United States Code
Microform Edition © ProQuest LLC.
ProQuest LLC.
789 East Eisenhower Parkway
P.O. Box 1346
Ann Arbor, Ml 48106 - 1346
ACKNOWLEDGMENT
The w riter wishes to express his sincere appreciation
to Dr. H. H. Kramer, who suggested and directed the work,
for his constructive criticism , advice and encouragement
during the study, and to Elsie Mihelich Armstrong for the
analytical work, which was performed in a very capable and
cooperative manner.
TABLE OF CONTENTS
Page
ABSTRACT ....................................................................................................... i
INTRODUCTION .............................................................................................. 1
REVIEW OF LITERATURE ........................................................................... 2
MATERIALS AND METHODS ......................................................................... 9
Breeding Procedure ...................................................................... 9
Isolation of S ta rc h ................................... 12
Amylose Determination ............................................................. 13
Analysis For Percent of Starch ........................................ 15
RESULTS ......................................................................................................... 17
The Eight Parental Lines Used in Reciprocal
Crosses in 1950 ...................................................................... 10
The Effect of Gene Dosage on Phenotype ..................... 19
Evidence for the Heterozygosity of P7 For
the Sugary-2 Locus .................................................................. 24
Gene Dosage Effects on Amylose Content ..................... 26
The Effect of Dosage and Seed Size on the
Starch Fraction ......................................................................... 31
The Relationship Between Starch and Amylose
Content ........................................................................................... 36
The Water-Soluble KLysaccharides .................................... 37
DISCUSSION .................................................................................................. 41
SUMMARY ....................................... 46
LITERATURE CITED AND BIBLIOGRAPHY ........................................ 4&
VITA
LISTS OF TABLES AND FIGURES
List of Tables
Table Page
1. The Percent Amylose, Starch and Water-Soluble
Polysaccharides of the Eight Parental Lines............ 17
2. The Phenotype and Genotype of the Crosses
and Their Parents .......................................................... 20
3. The Percent Starch and Amylose of the Crosses
P7 x P3 and P7 x P4 .................................................................. 25
4. The Effects of Dosage of su on Amylose ..................... 27
5. The Effects of Dosage of su2 on Amylose 29
6. The Effects of Dosage of du on Amylose ..................... 30
7. The Effects of Dosage of su and Seed Size on
S ta rc h ................................................................................................ 31
S. The Effects of Dosage of su2 on Starch ..................... 33
9. The Effects of Dosage of du on Starch ........................ 35
10. The Percent of Water-soluble Polysaccharides
of Various Genotypes .............................. 39
List of Figures
Figure Page
1. The Phenotypic Effect of Dosage of su, in the
Presence of su?du .................................................................... 21
2. The Phenotype Effect of Dosage of su and su? .... 23
3. Relation Between Percent Starch and Percent
Amylose ............................................................................ 3#
ABSTRACT
In 1947, a cross was made between the two non-isogenic
lines, sudu, sugary, dull, x su2 > sugary-2.
In 1946, the F-, was selfed and segregation noted on
four of the F, ears for normal, dull, sugary and sugary-2
seeds.
Two different tester stocks were employed in 1949 to
identify the eight true breeding genotypes. One of these,
suamdu. amylaceous sugary, was used to determine the geno
typic constitution with respect to du. The other tester,
a homozygous suy stock, considered identical to su2> served
to identify the genotype with respect to su2. Seven of the
true breeding genotypes were thus isolated in 1949; the
remaining one, susupDu. was later found to be segregating
for the su2 gene.
In 1950 a selfed row was grown from each of the eight
genotypes, and reciprocal crosses were made between these
eight lines to obtain all possible combinations of the three
genes. Bulked pollen was used from each genotype. After
classification, the seecb were bulked within each genotype,
and weight in grams was taken of three 100 kernel samples.
Chemical analyses were made for percent starch, amylose
and water-soluble polysaccharides.
The su gene was most effective in reducing to tal
starch, su2 intermediate, and very little reduction resulted
from the du gene. Both Su and Su2 showed a high degree of
dominance for percent starch. Dosage effects were negligible
for starch content. No genic interaction occurred for
starch, the reduction in most genotypes resulting from the
action of su or su2 alone. Seed size, considerably reduced
in su genotypes, was strongly correlated with the amount of
carbohydrates present.
The su2 gene was most efficient in increasing amylose
content. A strong interaction was evident between su and
du for this fraction of the starch; su2 and du appear to
act additively in this respect. The trip le recessive,
susu2du, analyzed only 9% for starch, but 77% of this was
amylose. Comparable values for the normal genotype were
59% and 25% respectively. The normal alleles of au and du
were highly dominant for percent amylose, but Su2 was
incompletely dominant to su?. The effects of gene dosage
were somewhat more evident than for starch, but were s till
insignificant.
A highly significant negative correlation existed be
tween percent of starch and of amylose.
Water-soluble polysaccharides were associated with
the presence of the _su gene; the genotypes not homozygous
for th is gene had less than 1% of these constituents, with
five exceptions.
GENE DOSAGE EFFECTS ON CARBOHYDRATE
CONTENT OF CORN ENDOSPERM
INTRODUCTION
Within the past ten years increasing attention has
been given to the problem of developing crops which are
suitable for a specific industrial use. This has been
possible because of our increased knowledge concerning the
role of the gene in controlling chemical reactions, and be
cause of the development of more refined chemical techniques.
The work reported here concerns the problem of producing
a high amylose corn, with properties sim ilar to cellulose,
which would be of considerable value industrially because
of its ability to form strong films and fib ers. The project
was begun about five years ago, and is being carried out
cooperatively by the Departments of Agronomy and of Agricul
tural Chemistry of Purdue University. It has involved an
accumulation of most of the known endosperm genes, gnd the
genetic and chemical study of their action in affecting
development of the carbohydrates of the endosperm.
This phase of the study deals with the interaction of
the three endosperm genes sugary, su, sugary-2, su?,
and dull, du. Chemical determinations w ill be presented
for percent starch, amylose and water soluble polysaccharides
for most of the possible genotypes from the cross of two
non-isogenic lines, sugary dull x sugary-2.
