|Webster James A,|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 4, 1995
Publication Date: N/A
Interpretive Summary: The Russian wheat aphid (RWA) is a recent and serious pest of barley in the USA. All barley cultivars in production today are very susceptible to feeding damage caused by the RWA. Barley breeders are currently developing RWA-resistant cultivars as quickly as possible to combat the yield limiting effects of the RWA. Unfortunately, little information is available on the genetic control of RWA resistance. Withou this information, development of RWA-resistant barleys can be a very long and difficult process. To obtain the critical information needed for rapid cultivar development, a study was undertaken to determine the genetic control of RWA resistance in STARS-9301B, a RWA-resistant barley germplasm recently released by the USDA-ARS Plant Science Research Laboratory in Stillwater, Oklahoma. STARS-9301B was crossed with Morex, a susceptible malting barley cultivar. Genetic analysis was performed on the parents, F1, ,reciprocal F1, F2, backcross populations, and F2-derived F3 families. Results of this analysis indicate that RWA resistance is controlled by two genes. This crucial information will guide barley breeders in their development of RWA resistance breeding strategies for barley.
Technical Abstract: The Russian wheat aphid (RWA), Diuraphis noxia (Mordvilko), is a devastating pest of barley (Hordeum vulgare L.). An excellent source of RWA resistance (STARS-9301B) was recently released to the barley industry. This study was conducted to determine the genetic control of RWA resistance in STARS-9301B. Crosses were made between Morex, a susceptible malting barley cultivar, and STARS-9301B. Genetic analysis was performed on the parents, F1, reciprocal F1, F2, and BC populations, as well as 232 F2- derived F3 families. Segregation in the F2 and BC populations indicated multiple gene control. Thirteen F3 families were found to be homozygous resistant and 12 were homozygous susceptible, indicating that two genes control RWA resistance in STARS-9301B. Analysis of data from the F2 and BCs to both parents suggested recessive epistasis of the dominant gene on an incompletely dominant gene. The occurance of non-segregating (homozygous) F3 families with an intermediate reaction to RWA supports this hypothesis.