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.

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