Inheritance of Russian Wheat Aphid Resistance in Spring Barley Germplasm Line STARS-9577B
- D. W. Mornhinweg *,
- D. R. Porter and
- J. A. Webster
The Russian wheat aphid (RWA), Diuraphis noxia (Mordvilko), has become a major pest of barley (Hordeum vulgare L.) in the western USA. STARS-9577B (PI 591617), a six-rowed, spring barley germplasm line with a high level of resistance to RWA, was recently released to barley breeders for barley improvement. Understanding the inheritance of RWA resistance in this germplasm line is necessary for breeders to develop an effective strategy for utilization of this germplasm in their breeding programs. This greenhouse study was conducted to determine the genetic control of RWA resistance in STARS-9577B. Crosses were made between ‘Morex’, a susceptible, six-rowed, malting barley cultivar, and STARS-9577B. Genetic analyses were performed on reaction to RWA of parents, F1, reciprocal F1, F2, backcrosses (BC1F1) to both parents, and F2-derived F3 families. Reaction was based on a visual rating scale of 1 to 9 (1 = no damage, 9 = dead plant). Segregation in the F2 and BC1F1 populations indicated multiple gene control. Seventy-seven F3 families were found to be homozygous resistant and 18 homozygous susceptible, indicating two gene control of RWA resistance in STARS-9577B. Analysis of data from F2 and BC1F1 populations suggested RWA resistance in STARS-9577B is controlled by dominant alleles at two loci, with alleles at one locus conferring a high level of resistance and alleles at the other locus conferring an intermediate level of resistance only when recessive alleles are present at the first locus.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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