Systematic error introduced into sorghum yield data: Does the multiseed (msd) trait increase sorghum seed yield?

Authors: Gitz, Dennis; Baker, Jeffrey; Xin, Zhanguo; Lascano, Robert; Stout, John

Submitted to: American Journal of Plant Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/6/2019
Publication Date: 9/9/2019
Citation: Gitz, D.C., Baker, J.T., Xin, Z., Lascano, R.J., Stout, J.E. 2019. Systematic error introduced into sorghum yield data: Does the multiseed (msd) trait increase sorghum seed yield? American Journal of Plant Sciences. 10:1503-1516. https://doi.org/10.4236/ajps.2019.109106.
DOI: https://doi.org/10.4236/ajps.2019.109106

Interpretive Summary: A multiseeded sorghum line was developed with more than double the numbers of seeds than in a conventional line. Breeders thought that simply increasing seed numbers would result in greater seed yields. But, when the yield of the multiseeded sorghum was tested, it was lower than conventional lines. ARS scientists in Lubbock, TX wondered if the smaller seeds might have been lost during mechanized threshing and cleaning. It was found that two types of errors occur when cleaning seeds having large size differences, shattering of large seeds during threshing and loss of small seeds during cleaning. This result is important because it clearly demonstrates that the question of yield potential of the multiseed lines has not been settled and needs to be systematically examined. This finding is also important because it suggests that other, earlier studies of yield components that showed decreased yield with larger seeds were probably flawed because of such errors.

Technical Abstract: Multiseeded (msd) mutant sorghum lines with greatly increased seed numbers were developed. It was originally thought that the msd trait could increase yield by up to three times in comparison with the wild type from which the mutant was derived. However, in a small plot trial, msd seed yield was decreased as compared to the parent line. Herein we report results that msd seed yield remained either unchanged or slightly increased when compared to the parent line. We suggest that attempts to measure msd sorghum yield were complicated by systematic errors associated with post harvest processing methods including threshing and pneumatic winnowing equipment. When evaluating sorghum yield of types with different seed sizes, threshing and seed cleaning should be optimized for each sorghum line.