1a.Objectives (from AD-416):
Produce F3 populations of California-adapted barleys crossed with sources of genes for resistance to the Ug99 stem rust pathogen.
1b.Approach (from AD-416):
Make crosses between Ug99-resistant barley lines and various market types of barley adapted to California production. The Ug99 resistant lines will be from ICARDA/CIMMYT material previously tested by Brian Steffensen at University of Minnesota, hulless lines from UC Davis and spring 2-row barleys from Washington State University. The locally-adapted lines will include hulled spring barleys for malting. Conduct field evaluations of F2 populations for agronomic traits including cold tolerance and resistance to local diseases, then advance to the F3 generation for further testing. The materials resulting from this SCA will be available for further development and testing to select materials that are locally adapted and have resistance to Ug99. This SCA supports research conducted under National Program (NP) Number303, Plant Diseases. The research is conducted as part of ARS research project 5358-22000-035-00D, augmented by the FY2010 Program Increase for Research to Strengthen Grain Disease Research to Reduce World Hunger.
This research supports the national Ug99 barley breeding effort by evaluating Ug99-resistant feed barleys and other lines for agronomic adaptation to California conditions, and by producing derivative barley populations for further UG99 resistance assessment. This research relates to objective 1C of the in house project “Identify germplasm and increase seed for wheat and barley lines with resistance to stem rust Ug99”. The primary focus of the University of California, Davis (UCD), barley breeding program has been the incorporation of genes for resistance to Cereal Yellow Dwarf Virus (CYDV), and resistance to stem rust (Ug99) will be added to the CYDV material. We continued to advance previously mentioned segregating populations which used sources of resistance from other US programs as a long term solution. For the short term, the strategy is to identify sources of resistance that might already be available within the breeding program. Results from the 2012 Njoro screening for stem rust resistance show it is likely resistance will be deployed sooner from within already existing breeding lines. From within the mapping population (MP) of Butta 12 crossed to Madre Selva numerous lines were scored as resistant at Njoro. The CYDV resistant line MP179 was scored 1R/1R/5M in three observations whereas the USDA check ‘Bobs White’ Wheat was scored 100S on the third reading. MP 179 was used in several crosses. Our best malting line UC1322, resistant to CYDV, scored 1MRMS/5MRMS/5M compared to the nearby check which was 100S. Several new crosses were made to this line. Low scores were recorded for several malting lines which emerged from the 2010 and 2011 USDA Malt Lab with high malting scores. Additional low scores were recorded for our best six-rowed hulless advanced lines UC1317, UC1318, UC1319 and UC1321. A small number of our latest six-rowed feed barleys were tested and all had S pustules.