What's Changing from 55 Years of Sorghum Breeding?.

Estimating genetic gains in sorghum [Sorghum bicolor (L.) Moench] is necessary to review past and present research and to determine whether the current rates of improvement will meet future production demands. Defining the rate of yield gains has a profound impact on growers, land owners, input suppliers, scientists, investors, policy makers and others.

This study was conducted to determine the rate of genetic gain in yield and associated traits in grain sorghum over the past 50-60 years. A panel of sixty hybrids representing 50+ years of hybrid breeding and their respective parental lines from the Texas A&M AgriLife Research Sorghum Breeding Program and fourteen historical DuPont Pioneer hybrids were grown and evaluated across Texas in 2016.

Based on data from these trials, grain sorghum yields have increased .008 t ha^-1 annually in the both the Texas A&M and DuPont Pioneer sorghum breeding programs. Traits associated with yield including yield potential per plant, heterosis, test weight, panicle size, and grain number per panicle have also increased from long-term selection. Other traits such as leaf angle, days to maturity, plant height and yield stability had little to no change. The portion of yield gains in sorghum production attributed to plant breeding was 61%.

Compared to other field crops, the rate of genetic gain in sorghum has been slower.  Reasons to explain the slower gains include changes in production environments, shifts in trait priorities, reductions in research and development, and less than optimized heterotic groups. Despite a plurality of reasons for why the rate of genetic yield gains is slower in sorghum, emerging technologies in sorghum breeding (i.e., doubled haploids, genomic selection) could lead to future increases.