Variation 39 Calculus of variations 36 Genetics 36 Agronomy 25 Plant Breeding and Genetics 21 Plant Biotechnology 20 GENETICS : A Periodical Record Of Investigations Bearing On Heredity And Variation 19 Calculus of variation-- Analysis-- Mathematics 17 Agriculture 14 English language 13 Sociolinguistics 13 GENETICS: A PERIODICAL RECORD OF INVESTIGATIONS BEARING ON HEREDITY AND VARIATION 12 Calculus 10 Evolution 10 Human genetics 10 Linguistics 10 Mathematics 10 Agricultural Entomology 9 Differential equations 9 Dissertations, Academic (Ph.D) 9 GENETIC 9 Genetic Techniques 9 Genetic variation 9 Horticulture 9 Mathematical optimization 9 Plant Physiology 9 Plant physiology 9 Plantation Crops and Spices 9 Pomology and Floriculture 9 Soil Science and Agricultural Chemistry 9