Tag Archives: Genetics

Recent research: Improved genetic markers for grain yield and quality

The genetic control of grain yield is very complex and involves many genes controlling processes such as growth and reproduction. Although introducing specific important agronomic traits has led to large advances in grain yield in the water-limited bread wheat production environment of southern Australia, recent yield improvements have been made through incremental genetic advances often without wheat breeders and researchers knowing the underlying physiological mechanisms. If the genetic/physiological basis was better understood, targeted breeding efforts could more rapidly improve traits driving grain yield in target environments. This study investigated the trait and genetic basis of grain yield and quality in a locally adapted wheat population.

The researchers used a doubled haploid population made from a cross between a relatively drought-tolerant breeders’ line and Kukri, a locally adapted variety less tolerant of drought. Experiments were performed in 16 environments over four seasons in southern Australia which fell into three distinctive rainfall patterns. Kernels per square metre was a large driver of grain yield and was further explained by kernels per spikelet, a measure of fertility, indicating these are key traits for improving yield in the target environment. The researchers found nine genetic loci for grain yield across the growing areas, individually accounting for between 3 and 18% of genetic variance within their respective growing areas. The gene variant (allele) from the relatively drought-tolerant breeders’ line increased grain yield, kernels per square metre and kernels per spikelet at most loci detected, particularly in the more heat stressed environments.

This work has provided a better understanding of the occurrences of these important loci in the local wheat breeding pool, helping wheat breeders maintain or improve these traits when designing cross-breeding programs. Three new loci associated with grain yield have potential for use in marker-assisted selection in breeding programs targeting improving grain yield in southern Australia and other similar climates.

Corresponding author: Dion Bennett
Organisations: Australian Centre for Plant Functional Genomics, Australian Grain Technologies
International Maize and Wheat Improvement Centre (CIMMYT)
Publication: Bennet, D., Izanloo, A., Reynolds, M., Kuchel, H., Langridge, P. And Schnurbusch, T. (2012) Genetic dissection of grain yield and physical grain quality in bread wheat (Triticum aestivum L.) under water-limited environments. Theoretical and applied genetics, 125:255-271.
Link: doi: 10.1007/s00122-012-1831-9

“Recent research” is a series of short, regular posts highlighting recent research papers from the Waite Campus.

Bob Symons Lecture

Professor Dieter SollThe inaugural Bob Symons Lecture was given by Professor Dieter Soll on the evolution of the genetic code: a work in progress, if you missed this interesting lecture you can listen to the podcast.

At the time of its elucidation the genetic code was suggested to be universal in all organisms, and the result of a ‘frozen accident’ unable to evolve further even if the current state were suboptimal. How do we see the genetic code today – 40 years after the familiar ‘alphabet’ with 20 amino acids was established? Of course, the ‘genetic code’ is the product of its interpretation by the translational machinery and it is only static as long as the components of this machinery do not evolve or are strictly conserved between organisms. Professor Soll, with over 470 scientific publications, has led the team which discovered selenocysteine and pyrrolysine, the 21st and 22nd amino acids which are directly inserted into growing polypeptides during translation. Based on the realization that protein plasticity is a feature of living cells, man-made expansion of the genetic code has begun by adding non-standard amino acids to the repertoire of the cell. Professor Soll will discuss these present evolutionary developments and how they underpin the creation of new organisms in the realm of synthetic biology.

The 3rd Bob Symons lecture is named in honour of the former Emeritus Professor in Plant Science at the Waite. Professor Symons had a long and distinguished career with the University of Adelaide, joining the University in 1962. The main research by Professor Symons between 1962 and 1990 in the Department of Biochemistry focused upon understanding the structure and function of viral nucleic acids in relation to infectivity and the development of plant disease. However, he also contributed significantly to the understanding of protein synthesis and ribozyme activity. Professor Symons was also responsible for commercial applications of his research leading to the establishment of the first Australian company to produce and market molecular biological for research. In 1991, Professor Symons moved his research to the Waite Campus where he focused upon viral diseases of grapevine and established Waite Diagnostics which still provides a service to grape growers in the diagnosis and control of grapevine pathogens. He retired in 2002 due to ill health and passed away in October 2006.

The Inaugural Keith W Finlay Lecture

The inaugural Keith W Finlay Lecture was given by CSIRO fellow Dr Liz Dennis on the Genetics and Epigenetics of Flowering, if you missed this facinating lecture you can listen to the podcast.

Dr Liz Dennis

Dr Dennis is internationally recognised as a leading plant molecular biologist. Her contributions include defining the molecular pathway for low oxygen response in plants, studying cotton fibre development and unlocking the secrets of the regulation of flowering. Flowering is one of the most critical stages in the life of a plant. Genes controlling flowering time have been identified in both Arabidopsis and cereals and their regulation in response to environmental cues studied. Epigenetic regulation of genes is emerging as a major player in controlling development and response to environmental conditions. One of the best studied examples of epigenetic regulation occurs during vernalisation – the promotion of flowering by cold. Research by Dr Dennis and her team in both Arabidopsis and cereals, has shown that epigenetic regulation of genes prevents vernalisation responsive plants from being triggered to flower by the long days of autumn and flowering. In recognition of her contribution to plant molecular biology, Dr Dennis has been asked to deliver the inaugural Keith W Finlay Lecture.

Keith Warren Finlay was employed as the Senior Plant Breeder and Crop Geneticist at the Waite Campus of the University of Adelaide in 1955. During his time at the Waite (1955-1969), Finlay was responsible for building the reputation and scale of the Waite’s cereal breeding programs through his mechanical innovations and collection of large numbers of barley and wheat cultivars. After leaving the University, Finlay was the Deputy-Director General of the International Centre for the Improvement of Wheat and Maize influencing the development of plant breeding internationally. He died in 1980.