Evolving gene banks: improving diverse populations of crop and exotic germplasm with optimal contribution selection.

We simulated pre-breeding in evolving gene banks - populations of exotic and crop types undergoing optimal contribution selection for long-term genetic gain and management of population genetic diversity. The founder population was based on crosses between elite crop varieties and exotic lines of field pea (Pisum sativum) from the primary genepool, and was subjected to 30 cycles of recurrent selection for an economic index composed of four traits with low heritability: black spot resistance, flowering time and stem strength (measured on single plants), and grain yield (measured on whole plots). We compared a small population with low selection pressure, a large population with high selection pressure, and a large population with moderate selection pressure. Single seed descent was compared with S0-derived recurrent selection. Optimal contribution selection achieved higher index and lower population coancestry than truncation selection, which reached a plateau in index improvement after 40 years in the large population with high selection pressure. With optimal contribution selection, index doubled in 38 years in the small population with low selection pressure and 27-28 years in the large population with moderate selection pressure. Single seed descent increased the rate of improvement in index per cycle but also increased cycle time.

Translating science into the next generation meat quality program for Australian lamb.

This paper introduces a series of papers in the form of a special edition that reports phenotypic analyses done in parallel with genotypic analyses for the Australian Sheep Industry Cooperative Research Centre (Sheep CRC) using data generated from the information nucleus flock (INF). This has allowed new knowledge to be gained of the genetic, environment and management factors that impact on the carcase and eating quality, visual appeal, odour and health attributes of Australian lamb meat. The research described involved close collaboration with commercial partners across the supply chain in the sire breeding as well as the meat processing industries. This approach has enabled timely delivery and adoption of research results to industry in an unprecedented way and provides a good model for future research.

Conservative posterior ceramic restorations: a literature review.

Conservative ceramic restorations have much to offer to improve appearance and strengthen posterior teeth. The advent of resin bonding makes possible many designs for inlays, onlays, and partial coverage crowns. This review discusses conventional porcelain, Optec HSP porcelain, Dicor, and Cerapearl with emphasis on strengthening mechanisms, principles of preparations, accuracy of fit, and indications.

A note on the formation of optimal composite populations.

Two recently proposed methods for predicting the optimal breed contributions to a new composite breed are discussed. It is shown that these can both lead to incorrect solutions, and a reliable method is proposed.

SUBMATRICES OF INTERASSOCIATIONS FOR SCORING INTERRELATEDNESS WITHIN MATRICES AS AN INDEX OF PSYCHOLOGICAL DISTURBANCE.

A method is given whereby a matrix of interassociations between individuals can be divided to yield a submatrix which can in turn be used to score the degree of interrelatedness of the parent matrix. The method can be appIied to determine the significance of .the difference between the inter- relatedness of two or more parent matrices. The method is applied to a small study of normal and distunbed subjects, and provides promising results.