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X. Genetics and Breeding of Malting Barley

X. Genetics and Breeding of Malting Barley

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MALTING BARLEY IN THE UNITED STATES



35 1



(1951) and Nilan (1964) have made excellent reviews of these studies.

The complexity of inheritance of agronomic characteristics ranges widely

from traits such as maturity and plant height, where individual F, plant

selection is effective, to grain yield, which requires extensive progeny testing in replicated trials. Most of the disease characteristics are relatively

simply inherited and can be manipulated in a breeding program if either

natural or artificial epiphytotics are available to obtain a selection differeential. A common experience encountered, however, is that the desired

disease resistance often is available only in exotic, unadapted material containing undesired genes. Several crosses with adapted malting barley varieties or the growing of extremely large populations of single crosses often

are required to break the linkages between the disease resistance gene or

genes and the undesired genes.

The genetics of malting quality characteristics are less understood than

most of the agronomic and disease characteristics handled by the barley

breeder. The unavailability of adequate testing procedures to most breeders

and the complexity of inheritance of quality characteristics have been contributing factors to the lack of understanding. The recognition of the relationship of kernel protein levels to malting quality caused the initation of

some of the first genetic studies of quality to be made on kernel protein.

Recent genetic studies have been concerned with enzymatic activity and

other quality characteristics. Reviews of these inheritance studies along

with application of the results to development of improvement of malting

quality have been made by Smith (1951 ), Nilan (1964), Bell and Lupton

(1962), and Meredith et al. (1962).

The development of “prediction tests” which involve chemical analyses

of the barley grain for percent protein, potential diastatic power, and percent extract has provided the barley breeder with a means for predicting

malting quality of lines in early generations. The prediction test frequently

is supplemented by kernel plumpness evaluations. Sisler and Banasik

(195 1 ) found that selection in the F, generation of a barley cross for kernel weight, percent nitrogen, diastatic power, and percent extract increased

the proportion of lines with acceptable quality. The effectiveness of selection for the individual characters was not presented. Bendelow and Meredith (1955) showed the prediction test was 79 % effective in selecting lines

which were favorable for quality, based on later malting quality tests. They

indicated that in some instances desirable lines would be discarded, but

knowledge of the parentage would be helpful in the selection of lines.

Some of the most useful information that can be used by the plant

breeder in selecting for malting quality characteristics is provided by recent

studies on estimates of heritabilities and genetic variances (Day et al.,

1955; Rasmusson and Glass, 1965, 1967; Rutger et al., 1966; Foster et al.,



352



0. A. PETERSON AND A. E. FOSTER



1967; Baker et ul., 1968). With the exception of results by Rutger

et al. (1966), these studies are based on tests on the barley grain rather

than on malt. Although heritability estimates from the various studies cannot be compared directly because of different methods of computation,

genetic variance of populations, and different generations involved, a

general evaluation of the effectiveness of selection in hybrid populations

can be made for the various malting quality characteristics. Quality measurements made on an individual F, plant basis appear unsatisfactory.

Selection for potential diastatic power, which is primarily a measure of

p-amylase in these studies, is effective using grain from a single F, plot.

Results from single plot data in the F, generation indicate that selection

would be advantageous for barley extract, kernel plumpness, and kernel

weight. Of course, delay of selection to the F, or F, generation would

improve chances of retaining desirable hybrid lines. Heritability estimates

for barley protein or nitrogen have been quite variable. Variable estimates

are expected because of the large influence of the environment on this

characteristic. However, selection in the F, generation for barley protein

or nitrogen appears to have merit if genetic variances are adequate. The

use of more than one replication, location, or year improves the selection

advantage, but the extra expense and time involved does not appear to

override the use of Fa selection for barley protein or nitrogen. Rutger et

al. (1966) evaluated several physical and chemical quality properties on

both barley and malt in the F, generation and found heritability estimates

exceeding 0.67 for all characteristics except barley nitrogen and wort nitrogen. Although heritability values may be satisfactory for the measurable

quality characteristics, the barley breeder must combine desirable levels

of the several traits into a single genotype which meets the standards of

the user of malt. These levels must be maintained under fluctuations in

the environment that occur in the area of production. Another problem

of great concern to the barley breeder is the inability to select for some

quality characteristics of importance to the brewer, because techniques to

evaluate these characteristics are not available to test hybrid progenies in

a breeding program. Flavor and filtration in the brewhouse are examples

of such characteristics.



B. HISTORY

OF ACCEPTABLE

MALTINGBARLEYVARIETIES

The classification of a barley variety as acceptable for malting and brewing involves much testing. The types of quality evaluations to which a barley line is subjected before achieving quality acceptance will be discussed

in a later section. Collaboration between agricultural experiment stations



MALTING BARLEY IN THE UNITED STATES



353



and the malting and brewing industry is involved in the classification of

a variety as acceptable for malting.

Several industrially sponsored organizations dating back to the 1930’s

have been concerned with the testing and classification of malting barley

varieties (P. E. Pawlisch, personal communication). Initially, the

United States Maltsters Association and the Barley Improvement Council

coordinated the industry effort to improve malting barley and assisted in

the establishment of the USDA National Barley and Malt Laboratory. The

Malt Research Institute was established in 1939, and one of its functions

was to evaluate varieties and submit their approval of those acceptable

for malting. The Midwest Barley Improvement Association was organized

in 1945 and renamed the Malting Barley Improvement Association in

1954. The Malt Research Institute merged with the Malting Barley Improvement Association in 1959 and since then the Malting Barley Improvement Association has been the sole organization sponsored by industry for the evaluation and approval of malting barley varieties. Members

of this organization consist of commercial maltsters, malting brewers, the

United States Brewer’s Association and Master Brewers Association of

America. In addition to the aforementioned functions, they have been involved in several other pursuits with malting barley including financial support to malting barley breeding programs at several state agricultural experiment stations.

A compIete list of varieties that have been approved as acceptable malting and brewing types in the United States is given in Table VI. Under

present-day standards, most of the older varieties on the list no longer are

acceptable. All the varieties have the spring growth habit. Several other

spring and winter types not on the list have been or are being used by

industry, but they occupy a relatively minor part of the total market.

Examples of some of these varieties are six-rowed varieties such as

ATLAS and WINTER TENNESSEE and the two-rowed types, MORAVIAN and

CARLSBURG 11. Although some of the acceptable malting varieties are more

widely adapted than others, all the varieties generally produce favorable

quality barley only when grown in those environments for which they were

specifically selected.

Malting barley varieties available to producers have been the result of

direct introductions from foreign countries, of selections by breeders or

farmers from introductions with mixtures of barley types, or of hybridization followed by one of several breeding methods. The older barley varieeties used by the malting and brewing industry primarily were introductions

or selections from introductions. Suitable quality in these types usually was

a matter of chance. More recently, varietal release has resulted from plan-



T A B U VI

Barley Varieties Classified as Acceptable Malting and Brewing Types in the United States



Variety



Year

introduced

or released

to producers



HANNCHEN

O.A.C. 91

ODESSA

ODERBRUCKER

MANCHURIA

38

WISCONSIN

KINDRED

BAY

MONTCALM

MOORE

HANNA



1908

1910

1914

1917

1990

1999

1949

1945

1945

1948



PARKLAND

TIUILL



1956

1956

1957

1961

1961

1964

1965

1965

1966

1971

1971

1973

1973



BETZES

LARKEH



TROPHY

DICKSON

CONQUEST



PIROLINE

FIRLBECKS

I11

SEABET

VANGUARD

BEACON

KLAGEB



?



Source

USDA

Ontario Agricultural College

South Dakota

Wisconsin

North Dakota

Wisconsin

North Dakota

Michigan

Macdonald College

Wisconsin

California

Brandon, Manitoba

North Dakota

Montana

North Dakota

North Dakota

North Dakota

Brandon, Manitoba

Idaho, Washington

California, Oregon

Montana

Washington

North Dakota

Idaho, USDA



CI

No.

531

1470

182

4666

2947

5105

6969

7113

7149

7951



8106

10001

9438

6998

10648

10647

10968

11638

9558

10088

13847

11868

15480

15478



Row

No.



e

6

6

6

6

6

6

6

6

6

9

6

6



a

6

6

6

6



a

a

e

e

6



a



Aleurone

color

Colorless

Blue

Blue or colorless

Colorless

Blue

Colorless

Colorless

Colorless

Blue

Colorless

Colorless

Blue

Colorless

Colorless

Colorless

Colorless

Colorless

Blue

Colorless

Colorless

Colorless

Colorless

Colorless

Colorless



w



v,

P



Origin

Introduction

Selection from introduction

Introduction

Selection from introduction

Selection from introduction

Hybrid selection

Farmer selection

Hybrid selection

Hybrid selection

Hybrid selection

Selection from introduction

Hybrid selection

Hybrid selection

Introduction

Hybrid selection

Hybrid selection

Hybrid selection

Hybrid selection

Introduction

Introduction

Hybrid selection

Hybrid selection

Hybrid selection

Hybrid selection



F

?

cd



B



1

B

gd



8Z

?

B



MALTING BARLEY IN THE UNITED STATES



355



ned crosses with specific quality objectives in mind. The breeding of malting barley varieties in the United States is relatively new. A concentrated

effort has been devoted to this objective only within the last three decades.

The history of malting barley breeding involving the six-rowed types of

barley is slightly older than for the two-rowed barleys. TRAILLwas the first

six-rowed barley released to producers in the United States in which a

primary breeding objective involved acceptability as a malting variety.

TRAILL

maintained the quality performance of KINDRED, a farmer’s selection

which fortunately contained the quality characteristics desired by the maltsters and brewers. KINDRED

raised the level of performance for quality

above any six-rowed barley previously available and became the standard

of quality for industry. The short history of two-rowed malting barley

breeding in the United States is attested to by the fact that until the recent

release of SHABET and VANGUARD,

all two-rowed varieties used by industry

were of foreign origin. SHABETand VANGUARD are varieties developed

through the use of hybridization.

Present malting barley breeding programs in the United States involve

planned crosses of selected parental varieties followed by one of several

selection and testing procedures. The majority of the malting barley varieties released in the last two decades in the United States have been

through the use of the pedigree method of breeding, or this method with

slight modifications. SHABETis the only variety in Table VI which was

developed using the backcross breeding method.



C. MALTINGBARLEYBREEDINGACCOMPLISHMENTS

The history of the development of malting barley varieties in the United

States contains some interesting trends. Most of the information for this

section will pertain to barley production in the principal six-rowed malting

barley growing areas of the midwestern United States, but similar patterns

exist for other areas of malting barley production in this country. The

acceptance of new barley varieties by producers has been more rapid in

recent years than that experienced 15 years ago. Rapid increases of seedstocks, improved methods of seed distribution, and an awareness of producers to advantages of using improved seedstocks are some of the reasons

for the accelerated rate of new variety acceptance. Varietal history also

shows that the length of time a variety stays in production has decreased

in recent years. One of the undesirable features noted in the varietal history

of barley has been the trend toward a one variety culture. A single variety

grown over a large area is vulnerable to attack by various crop hazards,

as clearly pointed out by Horsfall et al. (1972). Varieties with acceptable

malting quality have been the dominant barleys grown in the Midwest.



356



0. A. PETERSON AND A. E. FOSTER



These malting types also are suitable for feed purposes, and in most instances perform as well as the better feed varieties. Generally, new varietal

releases have been an improvement over the older varieties in production

and have tended to dominate the barley acreage. Much effort by state agricultural experiment stations is devoted to developing barley varieties having superior performance while maintaining a required level of genetic

diversity among varieties. This effort must continue in order to reduce the

risk of loss of malting barley supplies and to give both the producers and

users a varietal choice to fit their particular need. However, only the acceptance of a variety by producers and users over time determines its

success.

Peterson (1972) made an overall assessment of the progress in the development of improved barley varieties by studying changes in agronomic,

disease, and quality characteristics over the past four decades. Agronomic,

disease, and quality values for the most popular varieties grown in the

Midwest during this period are given in Table VII. Compared with varieties such as MANCHURIA and WISCONSIN 3 8, which are relatively undesirable by present day standards, grain yields were increased significantly with

TRAILL and were raised again with DICKSON. A new level of improved straw

strength was achieved with TRAILL and has been maintained since

that time. Further improvements in this characteristic are a critical need

for the more productive areas. Short, stiff-strawed types may help solve

the lodging problem.

Although present malting barley varieties are slightly earlier and shorter

than older ones, changes since KINDRED up until now in these characteristics have been slight. The variation in test weight also has been relatively

small in the popular varieties.

The most significant improvements in barley varieties have been in the

area of improved disease resistance. Stem rust (Puccinia graminis tritici

Eriks. and Henn.) resistance was found in KINDRED and has been introduced into every variety of six-rowed malting barley released since

KINDRED. Resistance to the prevalent leaf spotting diseases was not attained

was the first variety with field resisuntil DICKSON was released. DICKSON

tance to three prevalent leaf spotting diseases, spot blotch (Helminthosporium sativum Pam., King, and Bakke), net blotch (Helminthosporium teres

Sacc.), and Septoria leaf blotch (Septoria pusserinii Sacc.). DICKSON

has

been a significant factor in stabilizing production in certain parts of the

major midwestern malting barley producing areas since varying levels of

these leaf spotting diseases may occur either singly or in all combinations

each year. The new variety BEACON has resistance to loose smut [Ustilago

nudu (Jens.) Rostr.] added to the disease resistance levels present in

DICKSON. Loose smut resistance also is present in the blue aleuroned vari-



TABLE VII

Agronomic, Disease, and Quality Comparisons of Six-Rowed Barley Varieties Produced in the Midwestern United States

and Utilized for Malting and Brewing During the Past Four Decades0



Variety



Year

released to

producers



Grain yield

(bu/acre)



Straw

lodging



Plump

kernels



Kernel

protein



Malt

extract



(%)



Leaf spot

score

(1-10)b



(%I



(%)



(%I



66

64

79

44

43

41

41



5.0

6.0

6.7

6.7

6.0

6.5

3.5



29.0

46.0

31.5

a1 .o

40.6

55.9

34.6



14.6

15.3

14.6

14.0

14.1

14.6

13.8



72.8

69.6

73.0

73.8

74.3

74.8

74.9



F



F



=!

z



Diastatic

power

( V



0

W



9



P



r

m



.e

MANCHURIA

WI~CONSIN

38

KINDRED



TRAILL

TROPHY

LARKER

DICKSON



1990

1929

1942

1956

1961

1961

1964



51.3

47.8

50.8

59.8

61 . O

61.6

68.2



189

154

233

204

227

226

225



2

J



E

C



5J



m

U

[n



Data obtained from a period of years and locations summary of barley grown in North Dakota (Peterson, 1979).

b Combined disease score for spot blotch, net blotch, and Septoria leaf blotch. 1 = no symptoms, 10 = severe symptoms.

Degrees Lovibond, a unit of wort color.



Z

,



H



5



z



358



G. A. PETERSON AND A. E. FOSTER



eties, CONQUEST and BONANZA. Recent evidence indicates that introduction

of resistance to leaf rust (Pucciniu hordei Otth.) and (Septoria avenue

Frank f. sp. trilicea T. Johnson) into the six-rowed malting types may

be needed.

The changes in kernel plumpness due to shifts in predominant barley

varieties has shown a cyclic trend over the last four decades. With the

difficulty of obtaining simultaneous improvement of all important characteristics with each new varietal release, it appears that occasionally a sacrifice has been made in kernel plumpness in order to improve other traits.

Since all the varieties listed in Table VII which occupied substantial

acreages in the Midwest have been acceptable malting types, consideration

of the trends of quality characteristics is of interest. Although changes in

kernel protein percent, malt extract percent, and diastatic power have occurred as a result of shifts in varieties, none of these changes since the

KINDRED era were very drastic. In fact, differences among recent varieties

often have not been greater than that expected from year-to-year quality

variations within a variety. The deviations in quality characteristics of sixrowed, white aleurone types since KINDRED have not been nearly as great

as those for many of the agronomic and disease traits.



XI.



Hybrid Malting Barley



Cultivated barley is a highly self-fertilized crop in most environments.

The characteristics which inhibit cross-pollination make it difficult to obtain hybrids through natural crossing. Barley pollinates while the spike is

partially to completely enclosed in the flag leaf sheath in many areas of

the United States and Canada. Opening of the florets is inhibited by the

flag leaf sheath and only a limited amount of pollen escapes from the

flower into the air. Attempts are being made to increase cross-pollination

percentages by incorporating genes for head emergence prior to flowering,

anther extrusion from florets, and increased pollen load into adapted varieties (Foster and Schooler, 1971; Hockett and Eslick, 1971). Barleys from

the USDA world collection and interspecific crosses have served as sources

of germplasm.

Genetic male sterility first was reported in barley by Suneson (1940).

Since that time many other genetic male steriles have been found (Hockett

and Eslick, 1971) and 19 different loci have been identified. Male steriles

probably existed long before their first being reported because discovery

of at least one male sterile plant in a field of barley is not uncommon.

Hockett and Eslick (1969) reported a spontaneous mutation rate for

genetic male sterility of one in 40,000 plants. However, the genetic male



MALTING BARLEY IN THE UNITED STATES



359



sterility could not be used to produce hybrid barley seed in large quantities

because production of entire populations of male sterile plants was not

possible. Wiebe (1960) proposed use of the chemical DDT in combination

with genetic male sterility to produce populations of male sterile plants.

He proposed that a gene for susceptibility to DDT, Ddt, could be tightly

linked to a gene for male fertility, Ms. Spraying a population segregating

for Ms-Ddt ms-ddt with DDT would leave only male sterile plants. The

failure to find an ms gene linked close enough to the ddt gene to severely

restrict crossovers has prevented this scheme from becoming operational.

Ramage (1965) proposed the use of a balanced tertiary trisomic (BTT)

system for production of hybrids. He proposed that the extra chromosome

carry a M s gene close enough to the breakpoint of the translocation to

prevent crossovers. In addition, a mature plant character, such as kernel

size, kernel shape, or plant color, would be linked to Ms so that trisomic

plants could be identified easily. Several feed-type hybrid barleys are being

produced commercially and utilize the BTT system without benefit of the

mature plant character. More recently, Wiebe and Ramage (1971) proposed incorporating a gene for albinism into the system so that hand rogueing would not be necessary. Wiebe (1972) reported additional modifications of the BTT and other systems for production of hybrids. A basic

requirement for the BTT system to work properly is that the extra chromosome is not transmitted through the pollen. Matchett (1972) found that

rate of pollen transmission of the extra chromosome depended on varietal

background and varied from 4 to 17%. Transmission of the extra chromosome through the pollen results in fertile trisomics in the desired male sterile female block of a hybrid seed production field. If these fertiles are not

removed, they provide pollen to surrounding male sterile plants, and male

sterile plants will be present in a farmers F, hybrid field.

Eslick (1971) presented alternative.methods to the BTT system for production of hybrid barley. He proposed the use of balanced male steriles

in combination with dominant preflowering selective genes. The proposed

systems require close linkages between male sterility genes and dominant

preflowering genes, and the genetic stocks have not been established.

Schooler (1967) reported finding a cytoplasmic male sterile in the progeny of an interspecific cross with H . jubatum cytoplasm. However, undesirable plant types associated with the cytoplasm and fertility restoration have

prevented the use of these stocks in developing acceptable F, hybrids.

Pfeifer (1 972) reported that the variety “Pennrad” has a normal cytoplasm and nonrestorer genes and that many other varieties have sterile

cytoplasms and fertility restorer genes. He indicated that no undesirable

side effects were observed and that fertility restoration was complete in

the F, hybrids.



3 60



G. A. PETERSON AND A. E. FOSTER



The malting quality of F, barley hybrids is of concern to the industrial

processors and to the barley breeders. A number of quality tests on F,

hybrids have been made. Most of the tests have been on small amounts

of material because hybrid plants were the result of hand pollination and

often of hand emasculation. Lofgren and Peterson (1962) made prediction

tests on unmalted barley and found that percent extract and percent plump

kernels usually were similar to the mean of the high-parent. Diastatic

power and percent nitrogen, although variable, were most often intermediate to the parents and near the mean of the low-parent, respectively. These

results were substantiated by Rasmusson et al. (1966) when they performed malting tests on 28 F, hybrids involving 8 parents of diverse malt

quality. Average percent extract was intermediate between the mid- and

high-parent mean, and average percent malt nitrogen and percent plump

kernels were similar to the low-parent and high-parent averages, respectively. The average of all F,’s was not different from the mid-parent average for percent wort nitrogen, ratio of wort to malt nitrogen, diastatic

power, a-amylase, or p-amylase. The F, hybrids with the best quality usually had one parent with acceptable malting quality, and they suggested

that both parents of a hybrid should have good malting quality in order

to have the best chance of obtaining an F, hybrid with good quality. Foster

and Peterson (1967) evaluated a diallel cross among four barley varieties

for quality. They noted that F, hybrids were similar in kernel plumpness,

slightly lower in kernel protein, and slightly higher in percent extract and

diastatic power than the mid-parental means. Foster (1971) reported results of malting tests on hybrid barley produced in large plots. The F,

hybrids had parents with unsuitable malting quality, and the hybrids also

had unsuitable malting quality.

Grain yields of barley F, hybrids have not been outstanding (Armstrong

et al., 1970; Foster and Peterson, 1967; Foster, 1967, 1969, 1971; Grissom, 1969). The F, hybrids have performed better, relative to the parents,

under good environmental conditions than under unfavorable environmental conditions. Present barley varieties which can serve as potential

parents have intermediate straw strength. Improvement in straw strength

and reduction in plant height of the parents will be necessary for the.F,

hybrids to express their yield potential under high fertility conditions.



XII.



Quality Testing Procedures Used to Develop Acceptable Malting

Barley Varieties



Tests have been developed which aid in the evaluation of hybrid selections and introduced material for their potential as future malting barley



MALTING BARLEY IN THE UNITED STATES



361



varieties. In many barley breeding programs a series of tests for quality

are used. The complexity and number of determinations of the tests increases as the amount of grain available for testing and homozygosity of

lines increases with advancing generations. Also, the number of hybrid

selections which can be evaluated in later generations becomes less because

of the complexity of the tests and expense involved. Selection based on

the preliminary tests aids in reducing numbers of selections in advanced

generations.

The purpose of this section is not to give a detailed discussion of the

methods used in evaluating barley or malt, but to illustrate the steps a

barley breeding team usually follows from making the initial cross to final

naming and releasing of an acceptable malting variety.

Methods for barley quality evaluation were reviewed by Dickson and

Burkhart (1956) and Dickson (1965). Meredith et al. (1962) extensively

reviewed the methods of quality evaluation used for barley and malt in

several of the quality laboratories in Canada, the United States, and

Europe. Dickson (1969) discussed tests used for malting quality, and Anderson et al. (1943) extended such information to include an interpretation of analytical data on barleys and malts with this interpretation helpful

to plant breeders in their selection programs.

New methods of quality evaluation are constantly being investigated and

incorporated into testing procedures on hybrid selections as new basic biochemical and physiological information becomes available. Much effort by

quality laboratories involves improvement in the efficiency and speed with

which barley selections can be analyzed for quality. The success of a malting barley breeding program is closely related to the number of barley

selections which can 'be evaluated for quality along with agronomic and

disease characteristics. The ability of small-scale quality tests to aid the

barley breeder in selecting for quality characteristics can only be determined by their relationship to plant scale malting and brewing tests.

A.



PREDICTION

TEST



The prediction test involves the determination of protein content, potential diastatic power, and percent extract on the barley grain. Kernel size

assortment also is determined using the standard %4 inch X % inch and

the %;4 inch x % inch sieves. Although 60 g are submitted for the prediction tests, actual evaluations usually involve only 36 g of barley grain. The

prediction test is conducted on grain from individual plant progenies normally beginning in the F, generation and may continue until the F, or

as long as selections are carried as individual lines. Barley in any generation

can be analyzed by the prediction test. However, Foster et al. (1967) have



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