ROBERT WAYNE ALLARD 1919–2003. research was on wheat cytogenetics, and aside from publishing his...

N A T I O N A L A C A D E M Y O F S C I E N C E S

R O B E R T W A Y N E A L L A R D1 9 1 9 – 2 0 0 3

A Biographical Memoir by

M I C H A E L T . C L E G G

Any opinions expressed in this memoir are those of the authorand do not necessarily reflect the views of the

National Academy of Sciences.

Biographical Memoirs

COPYRIGHT 2006NATIONAL ACADEMY OF SCIENCES

WASHINGTON, D.C.

ROBERT WAYNE ALLARD

September 3, 1919–March 25, 2003

B Y M I C H A E L T . C L E G G

ROBERT (“BOB”) WAYNE ALLARD made wide-ranging contributions to both basic and applied plant genetics. He be-

gan as a plant breeder and wrote one of the most successfulplant-breeding texts of his era, but his most important con-tributions were in evolutionary genetics. He was a founderof experimental plant population genetics and he infusedthe field with high standards of experimental and theoreti-cal rigor. His investigations ranged from elegant experi-ments to dissect the genetic factors responsible for quanti-tative genetic variation, to the study of gene-environmentinteractions, to the analysis of selection in long-term ex-perimental barley populations. But his most significant workwas encompassed in a series of papers on the genetics ofinbreeding populations, where he overturned conventionaldogma by showing that inbreeding plant populations havesubstantial levels of genetic variation. In the course of hiswork on inbreeding species, he turned to the characteriza-tion of the genetics of wild and naturalized species andcontributed to the origins of the field of plant ecologicalgenetics. He was also a teacher par excellence, training morethan 50 Ph.D. students and an even larger number ofpostdoctoral students over a career that spanned more than

4 B I O G R A P H I C A L M E M O I R S

50 years, and he led the University of California, Davis,Genetics Department to preeminence during the 1960s and1970s.

EARLY INFLUENCES

Bob Allard was born in the San Fernando Valley of Cali-fornia on September 3, 1919. In the years between the twoworld wars the San Fernando Valley was largely pastoraland Bob’s early years were spent on the family farm. Around1930 his father relocated his farming operation to the SanJoaquin Valley about 15 miles west of Modesto. Like manyfarmers of the era, Bob’s father cooperated with Universityof California agricultural researchers by dedicating a por-tion of his land to experimental trials. A UC Berkeley plantbreeder named W. W. Mackie maintained plots of lima andcommon beans on the Allard farm, and Bob was assignedthe task of assisting Mackie with the maintenance of theexperimental plots. This turned out to be the formativeexperience of Bob’s young life, because Mackie instilled inBob a lifelong fascination with the causes of phenotypicvariation. In an oral history interview, Bob much later re-called that Mackie introduced him to the new science ofMendelian genetics during this period, thereby contribut-ing to his later choice of scientific career.

In recounting these early experiences, Bob would pas-sionately describe the pleasure he took in listening to Mackieand in hearing his theories about genetic variation and itspractical exploitation. Bob was not a man to dwell on thepast; he strongly preferred to look toward the future. Hisoccasional recollections of Mackie were exceptional and re-flected the enduring impact of this period on his later sci-entific development. According to Bob’s much later memo-ries, Mackie was also interested in the ecological bases ofadaptation and he introduced Bob to other plant species

5R O B E R T W A Y N E A L L A R D

common in their Central Valley environment, including theslender wild oat (Avena barbata) that would later featureimportantly in some of Bob’s research.

It seems likely that Mackie influenced Bob’s decision toenter UC Davis as a student of agriculture in the fall of1937. During his undergraduate years Bob worked as a stu-dent assistant for Coit Suneson of the U.S. Department ofAgriculture, and this also had an enduring impact on Bob.Suneson, along with Harry Harlan and Gus Wiebe, was en-gaged in developing bulk populations of wheat and barley,known as composite cross populations. The theory at thetime was that bulk populations would both act as a reser-voir for useful genetic variation while at the same time evolv-ing toward greater adaptation under standard agriculturalconditions. Years later Bob would use these composite crosspopulations as a powerful resource for studies in experi-mental population genetics. These early experiences didmuch to define Bob’s approaches to plant genetics andthey serve to illustrate the powerful impact that scientificmentors can have on young minds.

After finishing his undergraduate training, Bob enteredthe graduate program at the University of Wisconsin, Madi-son. Certainly the biggest thing that happened to him atMadison was meeting and marrying Ann, his wife of 59years. On the rare occasions when Bob would talk about hisgraduate school days, his chief recollection was being calledinto World War II service just prior to the scheduled datefor his final dissertation defense. It seems that the univer-sity would not reschedule the defense, and Bob had to re-turn to Madison after the war to defend his thesis. Bob’sPh.D. research was on wheat cytogenetics, and aside frompublishing his dissertation work following the war, he neverreturned to this topic. There were strong influences at Madi-son, including Rubush G. Shands (his major professor),


Charles E. Allen, and R. A. Brink, but I always had thefeeling that Bob had a clear idea of his future researchdirections by the time he left Davis.

After entering World War II service, Bob was sent tothe Naval Supply School at Harvard. Later he was assignedto a research unit at Fort Detrick, Maryland, where he wasengaged in work on biowarfare, a subject he never discussed,except to say that he had been in a research unit for part ofthe war. Still, this provided Bob’s only postdoctoral train-ing and broadened his research experience.

In 1946 Bob returned to UC Davis as assistant professorof agronomy and assistant geneticist in the Agricultural Ex-periment Station, and he remained at Davis affiliated withthe Agronomy Department throughout his career. He washired as a bean breeder and his particular focus was on theimprovement of the lima bean. At that time Davis was abranch of the Berkeley College of Agriculture and had littleautonomy. It was also a very small school with fewer than800 students, most of whom were there for two-year termi-nal degrees in agriculture. Bob was an important player ina faculty generation that turned Davis from a small satelliteagriculture campus into a thriving and world-renowned uni-versity.

From the beginning Bob’s work blended both basic ge-netics and practical plant improvement. In the initial yearshe focused on both the identification of disease-resistancegenes and applications of the backcross method of breed-ing for the incorporation of disease resistance into elitelines of lima beans. The search for disease resistance genesled to an extended field trip to Central and South Americato collect wild relatives and primitive land race materials asgenetic resources for future breeding efforts. He later pub-lished an article for the California Dry Bean Research Con-ference on plant exploring in Latin America. The conserva-


tion of genetic resources remained an abiding interest, onethat was communicated to a number of Bob’s students.

At heart Bob was a geneticist, and along with his practi-cal work on lima bean improvement, he began to developgenetic markers in lima beans. These were largely seed coatmarkers based on an amazing range of seed coat color pat-terns. Bob and his early students patiently dissected theinheritance of these discrete color polymorphisms and thenemployed them as markers to study adaptive change in thelima bean. A particularly fascinating aspect of the colorpatterns was the interactions between different genetic fac-tors that lead to the mosaic patterns evident on the seedcoats. We learn and generalize from our empirical experi-ences, and these are based on the materials that we chooseto study. In Bob’s case the theme of gene interaction, basedin part on his observations of seed coat color patterns inthe lima bean, continued to dominate his thinking through-out his career.

The practical side of Bob’s program prospered in theseearly years. He released a number of new varieties of limabeans; one variety, “Mackie,” was named for his childhoodmentor. He also began work on a novel plant-breeding text.The book, Principles of Plant Breeding, published in 1960had an enormous impact and was ultimately translated into17 languages. It remained the premier plant-breeding textfor a generation. The book was novel because it empha-sized genetic principles rather than methods and this con-tributed to its great success. Bob was also a very fine writerand this, too, contributed to the wide acceptance of Prin-ciples of Plant Breeding. He took great pains with every-thing he wrote, and the result was always a model of clarityand precision. Bob would not put his name on a paperuntil he had worked through it carefully, reanalyzed thedata, and improved the exposition. He did not believe in


honorary authorships and he was very economical with cita-tions. His practice was to cite only essential supporting pa-pers.

For many years Bob’s plant-breeding colleagues urgedhim to write a second edition of Principles of Plant Breed-ing, and he promised to do so, but it was not until 1999,almost 15 years after Bob’s retirement and just four yearsbefore his death that a second edition was published. Bobadmitted that the second edition was really an entirely newbook that contained little carried over from the parent bookpublished 39 years earlier. The second book is really a plantpopulation genetics book that synthesizes a life’s study ofplant evolution. It is uniquely Bob, both in the lucidity ofthe writing and in the presentation and articulation of hisvision of evolutionary genetics.

QUANTITATIVE GENETICS

The field of quantitative genetics had a large impact onagricultural research in the 1940s and 1950s. The origins ofquantitative genetics derive from R. A. Fisher’s 1918 paperreconciling Mendelian genetics and Darwinian evolutionby natural selection. Quantitative, or biometrical, geneticsaims to partition phenotypic variation into genetic and en-vironmental components and it provides a scientific basisfor designing efficient schemes for selection. In later yearsBob recalled that while a student at Wisconsin, he had beeninfluenced by Sewall Wright, who along with R. A. Fisherwas the other great architect of the field of quantitativegenetics. It is clear from Bob’s later recollections that hewas anxious to move beyond lima bean breeding by master-ing the skills of quantitative genetics. During the academicyear 1954-1955, Bob found the opportunity to hone his skillsin statistics and quantitative genetics by taking a year’s sab-batical leave in Birmingham, England, to work with Ken-


neth Mather, one of the era’s leaders in quantitative genet-ics. A few years later, in 1960, he returned to England towork at Oxford with Norman J. T. Bailey, a leading statisti-cian in the field of mathematical genetics. These sabbati-cals had an enduring impact on Bob’s research directions.

In the middle 1950s Bob began to publish papers thatattacked various biometrical issues of the day. One paperwas devoted to maximum likelihood estimators for recom-bination, others focused on the analysis of various diallelecrosses, and still others concerned the problem of estimat-ing gene-environment interactions. He began publishingmore frequently in broadly based genetics journals ratherthan in agricultural journals so that his papers would reacha broader audience of geneticists. He also continued topublish on applied topics throughout his career. One pa-per of this period that deserves special mention is an el-egant dissection of the genetics of heading time in wheat(1965). In this paper Bob showed that a major gene con-trolled heading date, but he went beyond this to show howthe remaining phenotypic variation in heading date couldbe resolved into additional genetic components, revealingthe influence of multiple genetic factors of unequal effect.The paper pushed the approaches of quantitative geneticsto their experimental limits. By this time Bob’s researchhad evolved beyond the lima bean to exploit other plantspecies more appropriate for investigating basic questionsof quantitative genetics. By the early 1960s Bob’s lab wasregarded as a leading lab for the study of plant quantitativegenetics. Even as he achieved this goal, Bob was moving innew directions.

THE GENETICS OF INBREEDING POPULATIONS

Stimulated in part by his colleague G. Ledyard Stebbins,Bob began to investigate the genetics of inbreeding spe-


cies. In his classic 1950 book, Variation and Evolution inPlants, Stebbins had claimed that inbreeding plant popula-tions should be largely devoid of genetic variation. Theargument put forward by Stebbins was that inbreeding leadsto homozygosity and the superior inbred type should out-compete all other lines leading to a homogeneous popula-tion. Bob knew from his plant-breeding experiences thatinbreeding crops, such as lima beans, had large stores ofgenetic variation and showed rapid genetic responses toselection. Stebbins had repeated what was the conventionaldogma of the time, but this provided the stimulus for Bobto begin what became a classic series of experiments tocharacterize genetic variation in inbreeding plant species.Stebbins, for his part, encouraged this effort to look moredeeply at the genetics of inbreeding species. The quest ledBob into an entirely new field, ecological genetics, whichsought to combine population genetics with ecology, whereBob played a foundational role. It also began a series ofpapers on population studies in predominantly self-polli-nated species that spanned a period of more than 20 years.

The studies of inbreeding populations led Bob fromquantitative genetics into population genetics. Bob quicklyestablished the leading program on plant population ge-netics of the 1960s, and he and his students found novelways of approaching the fundamental questions of this field.One important innovation harked back to the compositecross populations of his early undergraduate days. At thetime, population genetics was dominated by Drosophila, partlybecause the short generation time of Drosophila permittedexperiments over many generations, thereby allowing thedirect observation of evolutionary changes in gene frequen-cies. Bob had become the custodian of the composite crosspopulations, and he quickly realized that the populationshe had helped synthesize in his youth would allow a mul-


tiple generation approach in longer-lived annual plant spe-cies as well. The basic reason rested on the fact that seedcould be stored over a number of years, allowing an investi-gator to analyze gene frequencies in past generations. Tosee how this worked it is necessary to describe the systemfor propagating the composite cross populations. The prac-tice was to advance the populations each year by growing anew generation under standard agricultural conditions atDavis, while also storing a portion of seed from each year’sharvest for several years. The saved seed would then berejuvenated by growing out a new generation every five yearsor so. This provided a parallel series of populations thatrepresented early, intermediate, and late generations. Bythe early 1960s the oldest populations had about a 30-yearhistory and the youngest had a history of only five or sixgenerations. Because of this scheme, the barley and wheatcomposite cross populations provided a unique resource tofollow changes in phenotypic traits, gene frequencies, anddisease resistance loci over 30 or more generations.

Bob used every tool available to study genetic change inthe composite cross populations, beginning with simplemorphological polymorphisms and quantitative charactersand moving on to isozymes and finally to restriction frag-ment length polymorphisms (RFLPs) near the end of hiscareer. Bob was among the first to adopt the isozyme methodwhen it appeared in the middle 1960s. Isozymes had anenormous impact, because for the first time they allowedthe investigator to sample a large number of genes thatcoded for various enzymatic proteins. Prior to this, studentsof population genetics were limited to morphological vari-ants, such as the seed coat color polymorphisms of limabean or to quantitative traits where the underlying geneswere impossible to resolve. Isozymes allowed one to samplemany individual gene products and to ask questions about


genome-wide levels of genetic variation. RFLPs offered theadvantages of isozymes while also permitting the investiga-tor to measure variation for portions of the genome that donot code for enzymatic proteins. Throughout his careerBob was always among the first to adopt new approaches toaddress scientific questions. He was undaunted by obstaclesor by the investment of effort associated with acquiring newtechnologies.

Regardless of the experimental approach employed instudying the composite cross populations, substantial changesin trait or gene frequencies were always observed over time,and these were too large to be ascribed to genetic drift,leaving selection as the only plausible explanation. The nextnatural question was, could selection be quantified at indi-vidual loci? Theodosius Dobzhansky and Sewall Wright haddeveloped approaches to the quantification of selection oninversion polymorphisms in Drosophila pseudoobscura, butthese depended on the assumption of random mating. Thebasic estimation technique was to derive transition equa-tions that predicted genotypic frequencies in one genera-tion based on their frequencies in previous generations af-ter accounting for the mating process. A set of weights thatmapped the predicted frequencies onto the observed fre-quencies quantified the strength of selection.

Barley is a predominantly self-fertilizing plant, so therandom mating assumption could not be employed. A quan-titative theory of mating and a method to estimate the pa-rameters of such a quantitative model was required. A quan-titative theory, known as the mixed-mating model, whichallowed for a mixture of self-fertilization and random out-crossing, had been published in 1951 by Fyfe and Bailey(the same Bailey that Bob had worked with on sabbatical inOxford, England). Bob and his students employed this modelto estimate the single outcrossing parameter that indexed


the mixed-mating model and to derive transition equationsto estimate selection in the composite cross and other popu-lations. The technique for estimating the proportion of out-crossing relied on another important property of plants;the fact that one can easily collect numerous progeny of asingle maternal plant as seed. With the use of marker genesit was possible to estimate the fraction of self-fertilizationand its complement—the fraction of outcrossing—from familystructured data.

Armed with a quantitative characterization of the mat-ing process one could quantify selection at individual markerloci. But self-fertilization has another important consequencethat rendered it impossible to attribute selection to the markerloci actually observed. Because self-fertilization leads tohomozygosity, effective recombination is greatly reduced andany statistical associations among different loci decay slowlyover time. Populations like the composite cross populations,with a relatively short history, would still retain statisticalassociations between loci from their initial composition. Boband his students initiated the theoretical study of the be-havior of linkage disequilibrium (the technical term forcorrelations between loci in allelic state) in mixed-matingsystems in the middle 1960s. At a time when computer simu-lations were just beginning to be applied to genetic prob-lems, they published an important simulation study describingthe complex behavior of linkage disequilibrium in predomi-nantly self-fertilizing populations. Later estimates of themagnitude of linkage disequilibrium in the composite crossand other populations showed that it was typically large.The conclusion was that chromosomal segments containingthe marker loci were subject to strong selection in virtuallyall observed cases, but that one could not resolve selectionto the level of individual loci.


Bob was not satisfied with the study of artificial popula-tions. The question he sought to answer was the broaderquestion concerning levels of genetic diversity in inbreed-ing populations of plants in nature. By the early 1960s hehad launched a program to study natural populations ofinbreeding plants, and this work included a broad varietyof species, including Avena species (wild oats), other grassesnative to California, such as fescue, and annual native Cali-fornia dicots, such as Collinsia species. These efforts beganan intensive period of ecological genetics research thatspanned nearly two decades. Avena barbata, the slenderwild oat, was a particular target of investigation during thisperiod. A. barbata is a naturalized component of the Cali-fornia oak savannah that was introduced into Californiaduring the Spanish Mission period from the Mediterraneanbasin (almost certainly from Spain). The time dimension isknown, and this meant that genetic changes over a two-hundred- to three-hundred-year period could be documented.

Near the end of his life Bob recalled having been in-troduced to Avena barbata by W. W. Mackie; once againthis powerful early influence determined a scientific direc-tion, and it was a fortunate choice, because A. barbata showedmarkedly different patterns of evolution in different regionsof California. As later shown by two of Bob’s Spanish stu-dents (Marcelino Perez de la Vega and Pedro Garcia Garcia),these changes were not replicated in Spain, so they musthave arisen since the introduction of A. barbata to Califor-nia. Particularly dramatic were contrasting patterns of isozymevariation between the foothills of the arid Central Valley ofCalifornia and the cooler and moister intermontane valleysof the costal strip. The arid regions were nearly monomor-phic for a single multilocus genotype, while populationsfrom the coastal regions exhibited substantial levels of vari-


ability. I was fortunate to play a role in these findings, andit was a wonderful way to start a research career.

INTERACTING GENETIC SYSTEMS

A pervasive theme of Bob’s research and writing was theimportance of interactions among genes, between genesand environments, and even among genotypes within popu-lations. Bob believed that context was essential and thatmarginal effects were less important. I recall Bob attribut-ing this belief in the importance of interactions to his earlymentor W. W. Mackie. Regardless of the source, it clearlydominated Bob’s thinking. This view went counter to con-ventional population genetics theory that is based on thenotion that complex systems can be characterized by mar-ginal gene frequency changes. It also went counter to quan-titative genetics theory where additive effects were thoughtto account for most variation. To this day the importanceof interaction remains an open question.

Beginning in the middle 1950s, Bob published experi-mental work on gene environmental interactions. In the1960s he turned to the problem of interactions among genesat different loci. His approach of measuring linkage dis-equilibrium as a surrogate for gene interactions was stimu-lated by the theoretical calculations of R. C. Lewontin andK. Kojima giving the precise relationship between selectionand recombination required for nonzero linkage disequi-libria. These highly simplified models showed that only non-additive selection over loci could retard recombination andmaintain permanent linkage disequilibrium. Thus Bob fo-cused on the estimation of linkage disequilibria in experi-mental plant populations as a means of detecting interac-tions. It later became clear that the existence of linkagedisequilibrium is neither necessary nor sufficient for theexistence of interlocus interactions, especially in inbreed-


ing systems. Despite this, Bob did show that correlationsamong loci could be pervasive in inbreeding plant popula-tions and that this would in turn affect their evolutionarypotential.

Together with his students, Bob studied the impact ofneighboring genotypes on the fitness of individual plants.This system of intergenotypic interactions creates a frequencydependent pattern of selection and widens the conditionsfor the maintenance of a genetic polymorphism. As withmuch of Bob’s work, theoretical calculations were supple-mented by direct measurements from experimental popu-lations to provide a predictive framework. Bob was also astrong proponent of the idea that genetic mixtures wouldperform better than single pure lines in an agriculturalcontext, although the evidence to support this view has beenmeager.

A LIFE’S ACCOMPLISHMENTS

As noted above, Bob worked in, and in some cases helpedfound, several distinct but related areas of plant genetics.He had an enduring impact on plant breeding, largelythrough his book but also through his early work in bio-metrical genetics. These contributions were later recognizedthrough the DeKalb-Pfizer distinguished career award ofthe Crop Science Society and the Crop Science Award ofthe American Society of Agronomy. Bob was elected to theNational Academy of Sciences in 1973, where he chose toaffiliate with the genetics section and later with the sectionon population biology, evolution, and ecology after it wasformed, rather than with the agricultural sections. This choiceillustrates that his first love was genetics, despite a lifelongdevotion to agriculture.

More than any other worker, Bob Allard is responsiblefor laying the rigorous experimental foundations for plant


population genetics, and he played a major role in meldingthe union of ecology and genetics that emerged as ecologi-cal genetics. Perhaps his most enduring scientific legacywas the series on population studies in predominantly self-pollinated species. This series illustrated one of Bob’s greateststrengths. He was first and foremost an empiricist who foundinnovative ways to test theory and to expand our empiricalunderstanding of genetic systems. His belief in interactionran counter to the dogma of his time and often led tointense arguments, but he never modified his views. He waspassionate about his scientific views and at times the strengthof his convictions seemed to overwhelm the available evi-dence. In retrospect, his intuition was excellent and hisviews have been largely vindicated.

Bob was a prolific teacher and mentor of graduate andpostdoctoral students. Altogether he trained 56 Ph.D.students, and he hosted numerous visiting scientists andpostdoctoral students; he also trained a host of M.S. stu-dents. He had a large number of international students,and many have become prominent figures in countriesaround the world. I recall students from all continents, andas a consequence he left a global intellectual legacy. Hetaught throughout his long tenure at UC Davis in both theDepartment of Agronomy and the Department of Genetics.He wrote a wonderful set of lecture notes on populationgenetics that were used in the introductory genetics courseat Davis. During the late 1960s, I encountered his lecturenotes as an undergraduate and immediately decided I wantedto study population genetics. He also taught in the intro-ductory genetics course for many years as well as a graduatecourse in quantitative genetics and an undergraduate coursein population genetics. He was not a classroom performer,but his lectures, like his writing, were clear and carefullyorganized to make a central point.


Around 1967 Bob became chair of the Department ofGenetics at UC Davis, where he served with energy andskill. He played a major role in bringing Th. Dobzhanskyand F. J. Ayala to Davis in the early 1970s and helped cata-pult the Department of Genetics to international preemi-nence. At its peak the department included among its fac-ulty five members of the National Academy of Sciences. Healso served on virtually every major committee of the uni-versity and for a period chaired the Davis division of theUC Academic Senate. Bob was an active member of theNational Academy Sciences, where he chaired Section 27for three years. He served on a number of National Re-search Council committees, including a committee that pro-duced several volumes on managing global genetic resources.He was unstintingly generous with his time, and he servedthe university and the academy he loved with great devo-tion.

Bob retired in 1986 but remained very active. He pub-lished a remarkable number of research papers during hisretirement, along with the new edition of his classic plant-breeding book. During this period, Bob and Ann Allardspent much of their time at their home at Bodega Bay onthe northern California coast. He loved walking on the sea-side cliffs examining plants, especially Avena barbata, andspeculating about their unique adaptations to the Califor-nia environment. He was always eager to entertain friendsand colleagues; evenings with the Allards at Bodega Baywere very special events. Bob loved wine and was an accom-plished student and collector of fine wines, so any dinnerwas resplendent with excellent wine. Bob finally had to leavehis Bodega Bay home about two years before his death,owing to the onset of Alzheimer’s disease and circulatorydifficulties. He died on March 25, 2003, in Davis at the ageof 83.


S E L E C T E D B I B L I O G R A P H Y

1946

With H. R. DeRose and R. J. Weaver. Some effects of plant growthregulators on seed germination and seedling development. Bot.Gaz. 107:575-583.

1954

With R. G. Shands. The inheritance of resistance to stem rust andpowdery mildew in cytologically stable wheats derived from Triti-cum timopheevi. Phytopathology 44:266-274

1956

The analysis of genic-environmental interactions by means of diallelecrosses. Genetics 41:305-318.

1960

Principles of Plant Breeding. New York: Wiley.With S. K. Jain. Population studies in predominantly self-pollinated

species. I. Evidence for heterozygote advantage in a closed popu-lation of barley. Proc. Natl. Acad. Sci. U. S. A. 46:1371-1377.

1963

With P. L. Workman. Population studies in predominantly self-pol-linated species. III. A matrix model for mixed selfing and ran-dom outcrossing. Proc. Natl. Acad. Sci. U. S. A. 48:1318-1325.

1964

With J. Weil. The mating system and genetic variability in naturalpopulations of Collinsia heterophylla. Evolution 18:515-525.

1965

With C. Wehrhahn. The detection and measurement of the effectsof individual genes involved in the inheritance of a quantitativecharacter in wheat. Genetics 51:109-119.


1966

With J. Harding and D. G. Smeltzer. Population studies in predomi-nantly self-pollinated species. IX. Frequency dependent selectionin Phaseolus lunatus. Proc. Natl. Acad. Sci. U. S. A. 56:99-104.

1967

With S. K. Jain and P. L. Workman. The genetics of inbreedingpopulations. Adv. Genet. 14:55-131.

1970

With A. H. D. Brown. Estimation of the mating system in openpollinated maize populations using isozyme polymorphisms. Ge-netics 66:133-145.

1972

With J. L. Hamrick. Microgeographical variation in allozyme fre-quencies in Avena barbata. Proc. Natl. Acad. Sci. U. S. A. 69:2000-2004.

With B. S. Weir and A. L. Kahler. Analysis of complex allozymepolymorphisms in a barley population. Genetics 72:505-523.

1973

With M. T. Clegg. Viability versus fecundity selection in the slenderwild oat Avena barbata L. Science 181:667-668.

1977

With W. T. Adams. The effect of polyploidy on phosphoglucoseisomerase diversity in Festuca microstachys. Proc. Natl. Acad. Sci.U. S. A. 74:1652-1656.

1981

With D. V. Shaw and A. L. Kahler. A multilocus estimator of matingsystem parameters in plant populations. Proc. Natl. Acad. Sci. U.S. A. 78:1298-1302.

1982

With O. Muona and R. K. Webster. Evolution of resistance toRhynchosporium secalis (Oud.) Davis in barley Composite CrossII. Theor. Appl. Genet. 61 209-214.


1984

With M. A. Saghai Maroof, R. A. Jorgensen, and K. Soliman. Riboso-mal DNA (rDNA) spacer-length (sl) variation in barley: Mende-lian inheritance, chromosomal location, and population dynam-ics. Proc. Natl. Acad. Sci. U. S. A. 81:8014-1018.

1987

With D. B. Wagner, G. K. Furnier, M. A. Saghai Maroof, S. M.Williams, and B. P. Dancik. Chloroplast DNA polymorphisms inlodgepole and jack pines and their hybrids. Proc. Natl. Acad. Sci.U. S. A. 84:2097-2100.

With Q. Zhang and R. K. Webster. Geographical distribution andassociations between resistance to four races of Rhynchosporiumsecalis. Phytopathology 77:352-357

1989

With B. K. Epperson. Spatial autocorrelation analysis of the distri-bution of genotypes within populations of lodgepole pine. Ge-netics 121:369-377.

With P. Garcia, F. J. Vences and M. Perez de la Vega. Allelic andgenotypic composition of ancestral Spanish and colonial Califor-nian gene pools of Avena barbata: Evolutionary implications.Genetics 122:687-694

1991

With D. B. Wagner. Pollen migration in predominantly self-fertiliz-ing plants: Barley. J. Hered. 32:302-304

1999

Principles of Plant Breeding. 2nd ed. New York: Wiley.

ROBERT WAYNE ALLARD 1919–2003. research was on wheat cytogenetics, and aside from publishing his...

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