During the 1994-95 season, 23,232 wheat plots
were evaluated. This represents a 14 % increase in the size of
the wheat breeding effort at OARDC in 1995, even though our personnel
levels dropped from five to three full-time people between planting
and harvesting of the 1994-95 crop.
Cooperative nurseries included the Uniform Eastern
Soft Red Winter Wheat Nursery, the Uniform Soft Red Winter Wheat
Advanced and Preliminary 4-State Nurseries, the Uniform Winter
Barley Nursery, the Soft Wheat Quality Observation Nursery, and
the CYMMT International Winter Wheat Powdery Mildew and `Winter
x Spring' Screening Nurseries.
Our research goal is to use the techniques of molecular
plant breeding (mapping genes and marker-assisted selection)
in conjunction with classical statistical plant-breeding
methods to improve the quality and marketability of the wheat
crop in Ohio.
Disease reactions of commercial cultivars. We
evaluated many commercial cultivars for reaction to powdery mildew,
leaf rust, Septoria leaf and glume blotch, and wheat yellow mosaic
in 1995 (Table 1). We now have nearly complete information on
how most cultivars respond to various diseases. This has not
been possible over the past 7 to 10 years because of the low levels
of certain diseases, like yellow mosaic virus, in field plots.
A number of cultivars are now available with high yield potential
and good disease resistance to powdery mildew, Septoria nodorum,
and yellow mosaic. Most cultivars still lack acceptable levels
of resistance to leaf rust. `Freedom' is still rated
as moderately resistant to powdery mildew. We have seen a few
fields of Freedom with powdery mildew on the upper leaves of the
plants, but actual yield loss was minimal, and fungicide applications
were not needed. `Glory' and `Hopewell'
are moderately resistant to powdery mildew, resistant to wheat
yellow mosaic, moderately susceptible to Septoria glume blotch,
and susceptible to leaf rust.
Resistance to head scab. Head
scab was common in field plots at South Charleston and Wooster.
Thus, we were able to evaluate the reaction of a number of commercial
cultivars at both locations. Generally, comparing cultivars for
resistance to scab has been difficult because of the dominant
influence of flowering date (maturity) on disease infection.
This year, rain fell over a number of days during anthesis at
both locations, and disease was fairly uniform across plots.
To determine if a relationship existed between cultivar maturity
and scab level, a correlation analysis was conducted between heading
date and scab severity for both locations. The analysis indicated
that scab severity was correlated only weakly with heading date
(r = 0.21), thus, a comparison among the cultivars was possible.
Cultivars Freedom and AGRA GR876 had low percentages of spikelet
infection per head in both plots (Table 2). `Grant'
and `AGRA GR962' had high levels of scab at both locations.
Thus, cultivars vary in their reaction to scab in the field.
Last year, we conducted greenhouse inoculation tests
to determine the response of certain cultivars and breeding lines
to scab. This year we repeated these greenhouse tests using Freedom,
Glory, Hopewell, some Chinese lines known to have resistance (Sumai
3 and Ning 7840), and some unknown germ plasm lines (Table 3).
The data indicated that Freedom had a similar level of resistance
as the resistant lines from China. All of the lines prevented
spread of the disease from the inoculated spikelet to other spikelets
in the head. Sumai 3 and Ning 7840 are being used in breeding
programs in other states, but appearently, Freedom and AGRA GR876
already have resistance to scab at a level similar to that of
the resistant parents. We do not know if we can select cultivars
with a greater level of resistance than Freedom.
Table 2. Average percentage of scab infected heads in wheat varieties planted at OARDC near Wooster and OARDC Western Branch near South Charleston, OH, in 1995.
_____________________________________________________________________________________________
Scab (%) Scab (%)
__________________ __________________
Brand andVariety Wooster Western Branch Brand and Variety Wooster Western Branch
_____________________________________________________________________________________________
AGRA GR876 6 12 Nosco Classic RW151 35 27
GR933 37 25
GR942 47 32 Pioneer 2510 20 28
GR962 70 75 2545 37 55
2548 25 21
Agripro Clements 23 43 2552 23 22
Elkhart 40 58 2571 25 21
Pontiac 30 15
Sawyer 35 32 Rupp RS927 28 23
Beck 105 35 32 SurGrow SG1550 25 30
109 28 32 SG1540 38 27
Certified Caldwell 50 38 Steyer Hoppes 37 27
Cardinal 17 20 Kilne 42 40
Clark ó 50 McLane 28 27
Dynasty 28 28 Podach 32 27
Excel 45 43 Rowland 35 30
Freedom 18 9
Glory 31 20 Stine 501 40 40
Grant 62 57
Hopewell 43 50 Terra SR204 32 27
Jackson 33 37 SR205 35 27
Madison 35 47
Wakefield 35 32 Thompson TS4020 32 27
TS5020 33 42
Countrymark 544 35 33
558 23 28 Voris V8040 43 ó
568 35 25
Wellman W9350 25 27
Greenland GL9400 43 47 W9420 36 37
W9540 32 33
Hytest Succession 32 32
_____________________________________________________________________________________________
LSD (P = 0.05) = 12 % at Wooster and 11 %
at Western Branch.
Table 3. Reaction of wheat lines and cultivars to artificial
inoculation with Fusarium graminearum in greenhouse
tests, 1995.
_______________________________________________
Line or cultivar % Affected florets/head*
_______________________________________________
Freedom 4.4
Hopewell 24.5
Glory 66.6
OH436 22.2
OH448 19.0
OH542 27.5
Mo91-349 28.8
Fu 5114 1.3
Ning 7840 7.3
Ning 8331 14.3
Sumai 3 15.3
Sumai 49 0.7
Zm 7430 21.5
Zm 7482 3.3
Zm 8707 18.2
Zm 8725 19.3
Zm 10782 11.8
_______________________________________________
LSD (P=0.05) 14.3
_______________________________________________
*mean of from 9 to 22 heads per wheat line.
An inheritance study of genes conditioning partial
resistance to head scab is being conducted in the greenhouse in
1995-96 and in the field in 1996-97. Resistant
lines include Freedom, ZM10782, Ning 7840, and Sumai 49. Dimuth
Siritunga has assayed the Chinese and U.S. parents with RAPD and
STS markers to determine polymorphic markers and the degree of
genetic diversity among these lines.
We can use video image analysis to determine the
extent of kernel shrivelling in scab-infected heads. Some cultivars,
such as Cardinal and Freedom, seem to exhibit less shrivelling
at a given level of infection than others, like AGRA brands GR876
and GR915.
Genetic control of milling and baking traits in
a `hard x soft' wheat cross. We
are using molecular markers and field data to clarify the gene
numbers, locations, and interactions for both hard and soft wheat
quality traits in a recombinant inbred population derived from
a `Clark's cream/NY-6432-18' cross. This work is
being conducted in cooperation with the USDA-ARS Soft Wheat
Quality Lab at Wooster; North Dakota State University; Cornell
University; the USDA-ARS Grain Utilization Lab in Peoria,
IL; the USDA-ARS Western Wheat Quality Lab; the USDA-ARS
Hard Wheat Quality Lab; and the USDA-ARS Spring Wheat Quality
Lab. Field trials are being grown in 1996 at Wooster and Manhattan,
Kansas. Analysis of the first 3 years of data indicates
that soft wheat milling traits possess extremely high heritabilities
(above 90 %), whereas protein and alkaline water retention capacity
are somewhat less heritable. Genetic correlations between soft
wheat quality traits are generally low to moderate. Softness
equivalent seems to be determined by one major gene, but we have
not found molecular markers with which it is associated.
Breeding soft wheats with increased protein strength.
Dimuth Siritunga's research project
is to determine if an association exists among specific glutenin
alleles, mixograph traits, and soft wheat quality traits in the
1993 and 1994 Eastern Uniform nurseries. Extensive variation
is present for glutenin alleles among elite eastern soft wheat
germplasm. Approximately 45 % of the lines possessed gluD5x-10y,
which has been associated with dough mixing traits among hard
wheats. The presence of gluD5x-10y was correlated positively
with dough mixing time and with flour yield.
Further study of the relationships between glutenin
loci and quality traits in soft wheat will be conducted in four
F2 populations developed from Eastern Soft Wheat germplasm. Preliminary
work identifying glutenin loci in progeny of these populations
will be performed in the summer of 1996.
Multivariate analysis of old and new soft wheat
quality characteristics. In 1989, 1993,
1994, and 1995, the Soft Wheat Quality Lab performed a quality
analysis on historical and modern wheats grown at several locations
in the eastern and southeastern U.S. These nurseries were grown
by us; Mark Sorrells, Ithaca, NY; and Barry Cunfer and Jerry Johnson
Griffin, GA. The quality data are being analyzed using cluster
analysis and other multivariable methods to determine quality
relationships between sets of cultivars, changes in quality associated
with year of release, and patterns in quality that may be associated
with geographical location of a breeding program.
Development of doubled haploids in small grains.
Doubled haploid populations have uses in inheritance studies
and in introgression of exotic germplasm. We have pollinated
wheat with maize to produce haploid wheat embryos. Emily Stowe
of the College of Wooster conducted her Senior Independent Study
project to determine if different auxin treatments would increase
the percentage of embryos formed. She also analyzed DNA from
the doubled haploids developed to determine if any maize DNA had
been translocated to wheat chromosomes. She did not find an auxin
treatment better than the published technique, nor did she find
any maize DNA in the wheat DH lines. In 1996, we tested two embryo
rescue methods and again did not find an improvement over the
published technique. We have increased the percentage of embryos
formed by learning to manipulate environmental conditions.
Introgression of genes from T. tauschii
into soft wheat backgrounds. Triticum
tauschii is the contributor of the D genome
of wheat. The Wheat Genetics Resource Center at Kansas State
University has been introgressing genes from T. tauschii
into hard wheat backgrounds. We are introgressing genes into
soft wheat backgrounds (Ohio breeding lines). We have selected
T. tauschii accessions that exhibit resistance to powdery
mildew and Stagonospora nodorum. The WGRC reports influences
on wheat yields and quality as well. We have successfully made
about 20 hybridizations. Larry Herald is continuing to hybridize
wheat and T. tauschii with the goal of germplasm release.
Reaction of breeding lines to diseases. The
bulk of our resistance program deals with screening the breeding
lines for reaction to powdery mildew and Septoria nodorum.
This year we included head scab in our screening procedure and
established a nursery to look at the advanced materials in the
field. A diversity of material exists in these nurseries and,
as usual, we see a wide variation in the reaction to these diseases.
We test for powdery mildew in the greenhouse and in the fields.
The greenhouse inoculation allows us to select lines with certain
genes for resistance to powdery mildew. We feel that Pm1,
Pm3b, and Pm17 would give us the best protection
in the field, so we are looking for lines with these genes. The
field testing permits us to see how well the resistance is holding
up in a field situation, or if quantitative types of resistance
are present in the line. Among the advanced lines 1-16,
none showed a high degree of resistance to all diseases, but some
look promising. In the advanced rod row nurseries, a number of
lines had low disease severities for powdery mildew, but fewer
had low severities to Septoria. The reactions to head
scab indicate that finding a line with as good resistance to scab
as Freedom will be difficult.
Yield of powdery mildew-resistant and -susceptible
varieties. We have completed a 3-year
study to determine the value of planting powdery mildew-resistant
varieties. Wooster was chosen as the site for the study, because
powdery mildew is a problem nearly every year and growers in the
area choose to grow resistant varieties. Field plots, with from
eight to 10 varieties and four replications, were established
using similar conventional tillage, fertility and weed control
each year. All plots were planted within 2 to 5 days after the
Hessian fly-free date and spring topdress consisted of 300 lb
ammonium nitrate applied in late March. Powdery mildew was monitored
on the upper three leaves of 10 plants per plot on a weekly basis
from stem elongation through flowering. Disease assessments,
taken as the percentage leaf area affected on each date, were
used to calculate area under the disease progress curve, so that
the amount of disease on a particular leaf or variety could be
compared on a season-long basis. Fungicides were applied to half
of the plots so that yield could be compared between plots with
and without powdery mildew.
These data indicate that resistant varieties protect
growers from yield loss, and the amount of yield loss is dependent
on the severity of the disease and the yield potential of the
variety. Fungicide application increased yield of even the resistant
varieties, which could have been in response to control of some
other disease or to the fungicide acting as a growth regulator
that enhances yield. The data also indicate that varieties are
available that do not sacrifice yield potential for resistance.
Effect of planting date on disease and yield.
Delaying the planting of wheat until
after the Hessian fly-safe date is a standard production
practice. We wanted to document what effect delayed planting
would have on disease levels and yield. Field plots were planted
on six different dates starting about 11 days prior to the Hessian
fly-safe date at Wooster (27 September) through 21 October. `Becker'
was chosen as the test variety because of its susceptibility to
disease. The mild temperatures in autumn permitted sufficient
growth of plants from all planting dates, and powdery mildew was
present on plants from each planting date. Powdery mildew increased
rapidly on all plants in the spring, such that no difference could
be seen in disease severity among the planting dates by flag leaf
emergence. Fungicide applications increased yield of plots planted
at each date, and the yield increase was similar at each date.
Yield was greatest for the plots planted on 29 September and
7 October (2 to 10 days after the Hessian fly-safe date) and was
lowest in plots planted on the first and last dates (16 September
and 21 October). Planting date has an effect on yield regardless
of the presence of disease.
The cost of fungicide sprayer tracks in wheat.
We attempted to answer the question,
`How much do you loose by running over wheat with ground
equipment during fungicide application?' We planted a
replicated field trial at the OARDC Northwest Branch using the
susceptible cultivar Dynasty and the moderately resistant cultivar
AGRA GR863. This site was chosen because of the moderately low
level of disease nearly every year. Treatments were: fungicide
applied at flag leaf emergence, sprayer driven through plot but
no fungicide spray, and no treatment or tracks. Plots were 20
ft wide and 85 ft long. The tractor-drawn spray equipment was
driven lengthwise through the center of plots. The entire plot
was harvested for yield. No significant difference in yield occurred
among treatments for either variety. Disease levels were very
low, and no yield loss was demonstrated for fungicide application.
No yield loss was detected between plots that had the equipment
driven through them and those that were not disturbed. Thus, yield
loss from running down wheat at flag leaf emergence appears to
be minimal.
Foliar fungicide testing. We
have continued our fungicide screening program to evaluate various
fungicides and timing of applications. Fungicide efficacy was
evaluated against a number of diseases on the cultivars Cardinal,
Becker, AGRA GR863, and Clark. All fungicide treatments reduced
the severity of powdery mildew and leaf rust. RH-7592, Bayleton
plus Dithane DF, and Bayleton applied at heading (GS10.3) resulted
in significantly lower levels of Septoria leaf blotch than untreated
plots or plots treated with other fungicides. All fungicide treatments,
except Bayleton plus Benlate, reduced the level of head scab,
but the degree of control was probably not effective in reducing
yield losses from this disease. Most treatments were effective
in increasing yield as compared to the control, except the Bayleton
plus Benlate combination. Test weights were affected by the prevalence
of head scab in each treatment, but those treatments that were
effective in controlling leaf rust provided the greatest response
in improved test weight as compared to the untreated control.
Evaluation of seed treatments for disease control
and yield. A number of seed treatments
were evaluated for control of seedborne scab and late season powdery
mildew on Becker wheat at Wooster. Laboratory germination tests
indicated that seeds treated with RTU Vitavax-Thiram, FV58, EX13,
Agrosol FL plus Dividend, and Vitavax 200 had significantly lower
germination than untreated seeds. Twelve of the 19 seed treatments
tested reduced the amount of F. graminearum recovered from
seeds as compared to the untreated seeds. At stem elongation,
plots planted with seeds treated with RTU-Vitavax-Thiram plus
FA12 and WEO 115082 had lower powdery mildew severity than plots
planted with untreated seeds. However, by boot stage, no difference
in the severity of powdery mildew occurred among seed treatment
plots. No significant difference occurred among seed treatments
for test weight or grain yield. Two weeks prior to harvest nearly
25 % of the heads in all plots were affected by Fusarium head
scab. The lack of a yield response to seed treatments and the
lower than normal test weights probably were due to the prevalence
of head scab.
Development of value-added oat cultivars with
increased groat percentage. A rapid screening
technique has been developed that combines the use of Digital
Image Analysis with classification according to seed density and
size. This work is being conducted with assistance from the USDA
Soft Wheat Quality Lab and the Quaker Oats company. A yield trial
was planted in the spring of 1995, but was not harvested because
of poor, adverse environmental conditions at harvest. The nursery
will be planted again in 1997. We will assay the parents for
molecular marker polymorphism beginning this spring. Segregating
populations have been generated to determine the inheritance of
groat percentage and agronomic traits.
Personnel changes. Full-time
technicians Richard Minyo and Brenda Shult were lost to the program
because of downsizing resulting from budgetary constraints. Dimuth
Siritunga began work towards his Master's degree investigating
associations between specific glutenin alleles, mixograph trains,
and soft wheat quality traits. Emily Stow, a graduate of the
College of Wooster, has been hired on a part-time basis to conduct
digital image analysis, lab studies, and embryo rescue.
Publications.
Campbell KG, Herald LD, Minyo RJ, Hoover T, and Schult
B. 1994. Soft red winter wheat breeding and genetics. In:
Agronomy and Plant Pathology Dept `Soybean and small grains
varietal development'. OSU/OARDC.
Campbell KG and Lipps P. 1995. Rain brings wheat
scab epidemic. Ohio Farmer, Sept 1995. Pp. 24-27.
Gooding RW. 1993. Registration of `Armor'
oat. Crop Sci 33:876.
Gooding RW. 1993. Ohio performance trials of spring
oat cultirvars. Agron Dept Ser 200.
Gooding RW. 1994. Ohio performance trials of spring
oat cultirvars. Agron Dept Ser 200.
Gooding RW, Campbell KG, and Herald LD. 1995. Small
grains breeding and genetics. In: Agronomy and Plant
Pathology Dept `Soybean and small grains varietal development'.
OSU/OARDC.
Gooding RW, Campbell KG, Herald LD, Minyo RJ, and
Schult B. 1995. Ohio performance trials of spring oat cultivars.
Hort and Crop Sci Ser 200.
Gooding RW, Campbell KG, and Herald LD. 1996. Ohio
performance trials of spring oat cultivars. Hort and Crop Sci
Ser 200.
Jordan DM. 1993. Ohio soft red wheat performance
test. Agron Dept Ser 228.
Jordan DM. 1994. Ohio soft red wheat performance
test. Agron Dept Ser 228.
Jordan DM. 1995. Ohio soft red wheat performance
test. Hort and Crop Sci Ser 228.
Lipps PE and Johnston AL. 1993. Effects of fungicides,
row width, and seeding rate on powdery mildew severity and yield
of wheat. Phytopath 83:1387.
Lipps PE and Johnston AL. 1993. Efficacy of foliar
fungicides for control of powdery mildew and Septoria nodorum
on wheat in Ohio, 1992. Fungicide and Nematicide Tests 48:235.
Lipps PE and Johnston AL. 1993. Effect of wheat
seed treatments on powdery mildew control and on overwinter survival
of plants from Septoria nodorum infected seed in
Ohio, 1992. Fungicide and Nematicide Tests 48:332.
Lipps PE and Johnston AL. 1994. Evaluation of foliar
fungicides for control of powdery mildew and leaf rust on wheat
in Ohio, 1993. Fungicide and Nematicide Tests 49:224.
Lipps PE and Johnston AL. 1994. Effect of seed
treatments on control of powdery mildew and seed borne Stagonospora
nodorum on Becker wheat in Ohio, 1993. Fungicide and Nematicide
Tests 49:308.
Lipps, P. E. and Johnston, A. L. 1995. Evaluation
of foliar fungicides for control of powdery mildew and Stagonospora
leaf and glume blotch on wheat in Ohio, 1994. Fungicide and Nematicide
Tests 50:229.
Lipps PE and Johnston AL. 1995. Effect of seed
treatments on control of powdery mildew and ssed borne Stagonospora
nodorum on AGRA GR863 wheat in Ohio, 1994. Fungicide and
Nematicide Tests 50:317.
Lipps PE and Johnston AL. 1995. Effect of seed treatments
on control of mowdery mildew and seed borne Stagonsspora
nodorum in conventional and no-tillage wheat in Ohio,
1994. Fungicide and Nematicide Tests 50:318-319.
Lipps PE and Johnston AL. 1995. Head scab reaction of selected winter
wheat cultivars and breeding lines to Fusarium
graminearum, 1994. Biological and Cultural Tests 10:117.
Persaud RR and Lipps PE. 1993. Virulence of Blumeria
graminis f. sp. tritici in Ohio. Phytopath 83:1335.
Persaud RR and Lipps PE. 1994. Powdery mildew resistance
genes in selected winter wheat lines and cultivars. Phytopath
84:1116.
Persaud RR, Lipps PE, and Campbell KG. 1994. Identification
of powdery mildew resistance genes in soft red winter wheat cultivars
and ohio breeding lines. Plant Dis 78:1072-1075.
Persaud RR, Lipps PE, and Campbell KG. 1994. Powdery
mildew resistance genes in selected winter wheat lines and cultivars.
Phytopath 84:1116.
Persaud RR and Lipps PE. 1995 Virulence genes and
virulence gene frequencies of Blumeria graminis f. sp.
tritici in Ohio. Plant Dis 79:494-499.