Biographical Memoirs Volume 89 (2007) / Chapter Skim
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ROBERT WAYNE ALLARD
ROBERT WAYNE ALLARD
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Biographical Memoirs VOLUME 89
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His investigations ranged from elegant experiments to dissect the genetic factors responsible for quantitative genetic variation, to the study of gene-environment interactions, to the analysis of selection in long-term experimental barley populations. But his most significant work was encompassed in a series of papers on the genetics of inbreeding populations, where he overturned conventional dogma by showing that inbreeding plant populations have substantial levels of genetic variation.
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This turned out to be the formative experience of Bob's young life, because Mackie instilled in Bob a lifelong fascination with the causes of phenotypic variation. In an oral history interview, Bob much later recalled that Mackie introduced him to the new science of Mendelian genetics during this period, thereby contributing to his later choice of scientific career.
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The theory at the time was that bulk populations would both act as a reservoir for useful genetic variation while at the same time evolving toward greater adaptation under standard agricultural conditions. Years later Bob would use these composite cross populations as a powerful resource for studies in experimental population genetics.
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The search for disease resistance genes led to an extended field trip to Central and South America to collect wild relatives and primitive land race materials as genetic resources for future breeding efforts. He later published an article for the California Dry Bean Research Conference on plant exploring in Latin America.
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These were largely seed coat markers based on an amazing range of seed coat color patterns. Bob and his early students patiently dissected the inheritance of these discrete color polymorphisms and then employed them as markers to study adaptive change in the lima bean.
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It is clear from Bob's later recollections that he was anxious to move beyond lima bean breeding by mastering the skills of quantitative genetics. During the academic year 1954-1955, Bob found the opportunity to hone his skills in statistics and quantitative genetics by taking a year's sabbatical leave in Birmingham, England, to work with Ken
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The paper pushed the approaches of quantitative genetics to their experimental limits. By this time Bob's research had evolved beyond the lima bean to exploit other plant species more appropriate for investigating basic questions of quantitative genetics.
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The studies of inbreeding populations led Bob from quantitative genetics into population genetics. Bob quickly established the leading program on plant population genetics of the 1960s, and he and his students found novel ways of approaching the fundamental questions of this field.
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By the early 1960s the oldest populations had about a 30-year history and the youngest had a history of only five or six generations. Because of this scheme, the barley and wheat composite cross populations provided a unique resource to follow changes in phenotypic traits, gene frequencies, and disease resistance loci over 30 or more generations.
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Regardless of the experimental approach employed in studying the composite cross populations, substantial changes in 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 next natural question was, could selection be quantified at individual loci?
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Populations like the composite cross populations, with a relatively short history, would still retain statistical associations between loci from their initial composition. Bob and his students initiated the theoretical study of the behavior of linkage disequilibrium (the technical term for correlations between loci in allelic state)
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By the early 1960s he had launched a program to study natural populations of inbreeding plants, and this work included a broad variety of species, including Avena species (wild oats) , other grasses native to California, such as fescue, and annual native California dicots, such as Collinsia species.
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Thus Bob focused on the estimation of linkage disequilibria in experimental plant populations as a means of detecting interactions. It later became clear that the existence of linkage disequilibrium is neither necessary nor sufficient for the existence of interlocus interactions, especially in inbreed
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These contributions were later recognized through the DeKalb-Pfizer distinguished career award of the Crop Science Society and the Crop Science Award of the American Society of Agronomy. Bob was elected to the National Academy of Sciences in 1973, where he chose to affiliate with the genetics section and later with the section on population biology, evolution, and ecology after it was formed, rather than with the agricultural sections.
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He wrote a wonderful set of lecture notes on population genetics that were used in the introductory genetics course at Davis. During the late 1960s, I encountered his lecture notes as an undergraduate and immediately decided I wanted to study population genetics.
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He published a remarkable number of research papers during his retirement, along with the new edition of his classic plantbreeding book. During this period, Bob and Ann Allard spent much of their time at their home at Bodega Bay on the northern California coast.
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Jain. Population studies in predominantly self-pollinated species.
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Viability versus fecundity selection in the slender wild oat Avena barbata L Science 181:667-668.
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Perez de la Vega. Allelic and genotypic composition of ancestral Spanish and colonial Califor nian gene pools of Avena barbata : Evolutionary implications.
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