2013 Annual Report
1a.Objectives (from AD-416):
The objectives of this proposal are to deliver.
1)an understanding of how the pathogen is causing disease and why the local isolates are so much more virulent on locally planted barley cultivars including ‘Lacey’ and ‘Tradition’,.
2)Potentially durable sources of resistance in barley, and.
3)barley mapping populations that will be utilized to characterize the genetics of resistance for the eventual movement resistance into high yielding, high quality local barley varieties.
1b.Approach (from AD-416):
We will use a multiple approaches to begin to characterize the spot form net blotch population in eastern Montana and western ND. These approaches include collecting and characterizing natural Pyrenophora teres f. maculata populations collected in the from eastern MT and western ND, using bi-parental P. teres f. maculata populations that segregate for virulence, screening the barley core collection (BCC) for lines harboring high levels of resistance to spot form net blotch, and beginning the development of populations from these BCC lines to characterize the genetics of the resistance. Using this multi-dimensional approach we will gain insight into how to best control this important disease that is new to this region.
Net form net blotch has arguably been the most damaging foliar disease in the Northern Great Plains for at least the last decade. However, more recently spot form net blotch has gained a major foothold in the North Dakota and Montana barley growing regions. This increase in importance of SFNB is likely due to a shift in virulence of the pathogen, a change in resistance in barley, or a combination of the two, resulting in SFNB epidemics in recent years. We have begun to address this problem by evaluating the genetics of pathogen virulence and host resistance/susceptibility to gain an understanding of how the pathogen (Pyrenophora teres f. maculata) is inducing disease and what resistance is available to overcome the virulence of the pathogen.
On the pathogen side, we have developed several populations through sexual crosses. Populations have been successfully made using highly virulent isolates collected from the Sydney, Montana barley growing region crossed with either avirulent P. teres isolates or diverse isolates from other regions of the world that differ in virulence. We have begun to phenotype these populations in order to evaluate the genetics of virulence associated with several currently planted barley varieties, including Tradition, Pinnacle, AC Metcalfe, Conrad, and Conlon, as well as resistant barley lines identified in a screen of the barley core collection.
On the host (barley) side, several crosses have been made between the popular barley varieties mentioned above and the resistant lines identified in the barley core collection. These crosses will be used in developing recombinant inbred populations that will eventually be mapped with molecular markers in order to characterize the genetics of SFNB resistance. Characterization of this resistance will be useful in the introgression of SFNB resistance into local varieties.