So far in this course we have dealt entirely with the evolution of characters that are controlled by simple Mendelian inheritance at a single locus. There are notes on the course website about gametic disequilibrium and how allele frequencies change at two loci simultaneously, but we didn’t discuss them. In every example we’ve considered we’ve imagined that we could understand something about evolution by examining the evolution of a single gene. That’s the domain of classical population genetics. For the next few weeks we’re going to be exploring a field that’s actually older than classical population genetics, although the approach we’ll be taking to it involves the use of population genetic machinery. If you know a little about the history of evolutionary biology, you may know that after the rediscovery of Mendel’s work in 1900 there was a heated debate between the “biometricians” (e.g., Galton and Pearson) and the “Mendelians” (e.g., de Vries, Correns, Bateson, and Morgan). Biometricians asserted that the really important variation in evolution didn’t follow Mendelian rules. Height, weight, skin color, and similar traits seemed to

Human biochemical genetics

Chapter 4 – SOLAR UV IRRADIATION AND THE GROWTH AND DEVELOPMENT OF HIGHER PLANTS

Many grazing animals in both terrestrial and aquatic ecosystems form dense herds that maintain the vegetation in their concentration areas at very low statures. Studies of the effects of large ungu...

Grazing Lawns: Animals in Herds, Plant Form, and Coevolution

Publisher Summary The chapter discusses the meaning and value of the biological yield and harvest index of cereals in agronomic studies and in cereal breeding. The relationship of biological yield, grain yield, and harvest index to each other and to other plant characteristics is discussed. Various models and actual relationships between biological yields and grain yields within a series of genotypes or agronomic treatments are described. The situation in which a number of varieties have precisely the same biological yield but different grain yields is graphically presented along with the genotypes that are ranked in order of increasing grain yield. Grain yield is proportional to harvest index and their correlation is 1.00, whereas biological yield and harvest index are unrelated. The chapter examines the interaction of biological yield, grain yield, and harvest index with plant density. Biological yield and harvest index are two valuable criteria for the assessment of the performance of cereals.

The Biological Yield and Harvest Index of Cereals as Agronomic and Plant Breeding Criteria

A procedure was developed for extraction of ‘free’ condensed tannins (CT) using a mixture of acetone/water/diethyl ether (4.7:2.0:3.3), followed by extraction of protein-bound and fibre-bound CT using boiling sodium dodecyl sulphate containing 2-mercaptoethanol (SDS). CT concentrations in all three fractions were determined by a modified butanol-HCI procedure. Separate standard curves using purified CT in water or SDS solution were utilised for analysis of extractable CT (water standards) and protein-bound and fibre-bound CT (SDS standards). The method accurately predicted the concentration of CT added to forage extracts. CT extractable in acetone/water/diethyl ether comprised, on average. 68% of total CT in a range of freeze dried forage legume samples, with most of the remainder being bound to protein. When total CT concentration was low (0.6-3.0% DM), a lower proportion was extractable (33-35%). In protein concentrate meals containing CT, the extractable, protein-bound and fibre-bound components comprised 15, 60 and 25% respectively of total CT. Total CT concentration in the forages Lotus corniculatus and Coronilla varia was considered appropriate for ruminant nutrition (2.1 and 3.0% DM). whilst CT concentration in the forage of Dorycnium spp (13–19% DM) was more suitable for soil conservation purposes. The substantial CT concentration in cottonseed meal (1.6% DM) may be involved in the high resistance of proteins in this product to ruminal degradation. CT concentration was indistinguishable from zero in perennial ryegrass forage, in barley and triticale grains and in soya bean meal (0.1% DM).

Determination of extractable and bound condensed tannin concentrations in forage plants, protein concentrate meals and cereal grains

Physiological aspects of crop yields.

https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1155&context=agronomyfacpub

Cytochromes and the succinic acid oxidase system of poky strains of Neurospora.

https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1156&context=agronomyfacpub

Studies on the respiratory system of the poky strain of Neurospora.

https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1172&context=agronomyfacpub

Francis A. Haskins

Papers

Physiological aspects of crop yields.

Cytochromes and the succinic acid oxidase system of poky strains of Neurospora.

Studies on the respiratory system of the poky strain of Neurospora.

Separation of enzymes on the filter paper chromatopile.

Changes in the Activities of Several Enzymes during Germination and Seedling Development in Corn (Zea mays L.).