AUTHOR=Kong Wenqian , Nabukalu Pheonah , Cox T. Stan , Goff Valorie H. , Pierce Gary J. , Lemke Cornelia , Robertson Jon S. , Compton Rosana , Tang Haibao , Paterson Andrew H. 

TITLE=Transmission Genetics of a Sorghum bicolor × S. halepense Backcross Populations

JOURNAL=Frontiers in Plant Science

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2020.00467

DOI=10.3389/fpls.2020.00467

ISSN=1664-462X

ABSTRACT=<p>Despite a “ploidy barrier,” interspecific crosses to wild and/or cultivated sorghum (<italic>Sorghum bicolor</italic>, 2n = 2x = 20) may have aided the spread across six continents of <italic>Sorghum halepense</italic>, also exemplifying risks of “transgene escape” from crops that could make weeds more difficult to control. Genetic maps of two BC<sub>1</sub>F<sub>1</sub> populations derived from crosses of <italic>S. bicolor</italic> (sorghum) and <italic>S. halepense</italic> with totals of 722 and 795 single nucleotide polymorphism (SNP) markers span 37 and 35 linkage groups, with 2–6 for each of the 10 basic sorghum chromosomes due to fragments covering different chromosomal portions or independent segregation from different <italic>S. halepense</italic> homologs. Segregation distortion favored <italic>S. halepense</italic> alleles on chromosomes 2 (1.06–4.68 Mb, near a fertility restoration gene), 7 (1.20–6.16 Mb), 8 (1.81–5.33 Mb, associated with gene conversion), and 9 (47.5–50.1 Mb); and <italic>S. bicolor</italic> alleles on chromosome 6 (0–40 Mb), which contains both a large heterochromatin block and the <italic>Ma1</italic> gene. Regions of the <italic>S. halepense</italic> genome that are recalcitrant to gene flow from sorghum might be exploited as part a multi-component system to reduce the likelihood of spread of transgenes or other modified genes. Its SNP profile suggests that chromosome segments from its respective progenitors <italic>S. bicolor</italic> and <italic>Sorghum propinquum</italic> have extensively recombined in <italic>S. halepense</italic>. This study reveals genomic regions that might discourage crop-to-weed gene escape, and provides a foundation for marker-trait association analysis to determine the genetic control of traits contributing to weediness, invasiveness, and perenniality of <italic>S. halepense</italic>.</p>