Richard E. Boyles, Brian K. Pfieffer, Elizabeth A. Cooper, Kelsey J. Zielinski, Matthew T. Myers, William L. Rooney and Stephen Kresovich (2017). Quantitative Trait Loci Mapping of Agronomic and Yield Traits in Two Grain Sorghum Biparental Families. Crop Science.
a Advanced Plant Technology Program, Clemson Univ., Clemson, South Carolina 29634
b Pee Dee Research and Education Center, Clemson Univ., 2200 Pocket Rd., Florence, SC, 29506
c Dep. of Soil and Crop Sciences, Texas A&M Univ., 2474 TAMU, College Station, TX 77843
d Plants for Human Health Institute, North Carolina State Univ., Kannapolis, NC, 28081
e Institute of Translational Genomics, Clemson Univ., Clemson, SC 29634
The animal industry is a major sector of agriculture in the southeastern United States, but a large deficit exists in regional feed grains needed to support the industry. An increase in production of sorghum [Sorghum bicolor (L.) Moench], a water- and nutrient-use-efficient cereal, on marginal lands could lead to an alternative crop option for growers and reduce the current grain deficit. Quantitative trait locus (QTL) mapping of grain yield components in two sorghum biparental recombinant inbred line (RIL) populations was performed to better understand the genetic basis of grain yield and characterize these traits in a marginal environment. A more robust knowledge of the genetics underlying these complex traits could provide insights into molecular breeding strategies that aim to increase genetic gain. Specific yield traits investigated were grain number per primary panicle (GNP), 1000-grain weight (TGW), and grain yield per primary panicle (YPP). Two-year phenotyping in the South Carolina coastal plain revealed greater than threefold variation for both GNP and YPP, whereas TGW variation was just above twofold in both RIL families. There were 16 total yield trait QTL identified across both populations. Of the 16, eight QTL colocated with previously published QTL for yield-related traits, including a QTL on chromosome 1 that was significant for all three grain yield components. A novel QTL for TGW was identified on chromosome 5 that explained >21% of the phenotypic variance observed in one RIL population. This QTL and the seven additional novel QTL identified in this study provide new targets for grain yield improvement in sorghum.