AUTHOR=Crespo-Herrera Leonardo , Singh Ravi P. , Reynolds Matthew , Huerta-Espino Julio 

TITLE=Genetics of Greenbug Resistance in Synthetic Hexaploid Wheat Derived Germplasm

JOURNAL=Frontiers in Plant Science

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2019.00782

DOI=10.3389/fpls.2019.00782

ISSN=1664-462X

ABSTRACT=<p>The greenbug, <italic>Schizaphis graminum</italic> Rondani, significantly reduces wheat, <italic>Triticum aestivum</italic> L., grain yields if not controlled. Host plant resistance (HPR) can protect yield, is environmentally friendly and easy to use. Our objectives were to: (1) identify genomic regions associated with <italic>S. graminum</italic> resistance in a recombinant inbred line (RIL) population derived from a cross of “Sokoll” (resistant) and “Weebill1” (moderately susceptible), (2) evaluate Sokoll derived breeding germplasm for resistance, and (3) conduct allelism tests between Sokoll and sources carrying resistance genes <italic>Gba</italic>, <italic>Gbb</italic>, and <italic>Gbd</italic>. Resistance was measured quantitatively and qualitatively using a SPAD meter and visual assessments, respectively. We identified a large effect resistance gene on chromosome arm 7DL of Sokoll, herein referred as <italic>GbSkl</italic>, which contributed up to 24% of the phenotypic variation. Other minor QTL on chromosomes 2B, 3A, and 7B were also identified. The QTL on 2B and 3A originated from Weebill1. Of the Sokoll derived germplasm, 13% displayed resistance. Allelism tests indicated that <italic>GbSkl</italic> could be allelic or tightly linked to the temporarily designated genes <italic>Gba</italic>, <italic>Gbb</italic>, and <italic>Gbd</italic>. Utility of SPAD to determine quantitative variation in resistance phenotyping is demonstrated and breeding efforts are underway to transfer the resistance from Sokoll to new CIMMYT elite germplasm.</p>