Section 5: Wheat Scab Research

Transcription

1 Section 5: Wheat Scab Research One of the primary research objectives of the Virginia Tech wheat breeding program is to identify and develop cultivars possessing resistance to Fusarium Head Blight (FHB) or scab. In 2017, all wheat entries in Virginia s Official State Variety Trials were evaluated for FHB resistance in an inoculated, irrigated nursery at the Virginia Crop Improvement Association (VCIA) test site in Mt. Holly, VA. Data from this test for the current crop year and two-year average for FHB incidence, FHB severity and FHB Index (incidence x severity / 100) are included in this bulletin (Table 32) to aid producers in selection of cultivars on the basis of FHB resistance. Cultivars possessing complete resistance or immunity to FHB have not been identified and resistance levels in currently available cultivars vary from moderately resistant to highly susceptible. A major goal of the breeding program is to identify and incorporate unique and complementary types of FHB resistance into cultivars to enhance the overall level of resistance. Genes controlling FHB resistance have been identified on more than six chromosomes in wheat and some of these genes are complementary in nature and effect different disease resistance components such as FHB incidence, severity, and DON toxin content. Incorporating such multiple resistance genes having additive effects on FHB resistance into cultivars will enhance the overall level of resistance. Because the individual resistance genes are located on different wheat chromosomes and each gene confers only partial resistance to FHB, identifying wheat lines having multiple resistance genes is difficult using traditional breeding techniques. To overcome this limitation, our program is currently identifying and using DNA markers located close to these resistance genes on the same chromosome as tags for selecting wheat lines possessing different combinations of these complementary resistance genes. In 2017, entries were inoculated by spreading scabby corn kernels (50g/4-rows) in plots at the booting stage. Among 139 lines and varieties tested in 2017, the FHB index varied from 2.8 to 51.6 with FHB incidence ranging from 25% to 75% and FHB severity ranging from 5.9% to 70.1% (Table 31). Seventy-eight lines and varieties had FHB index values lower than the mean (<15.3) and expressed moderate resistant to FHB in Based on two year mean data for 2016 and 2017 (Table 32), eight lines and 26 varieties had FHB index values lower than the test mean (<15.9). 87

2 Line (0-100) (Julian) Index USG MBX 17-P VA13W AgriMAXX MAS # AgriMAXX USG MDX #Bullet Dyna-Gro AgriMAXX PGX Dyna-Gro Dyna-Gro CROPLAN USG VA13W MAX VA12W SY Southern Harvest MDX MAX Dyna-Gro MAS # USG VA12W VA09MAS Armor Mayhem MAX CROPLAN Southern Harvest Dyna-Gro DH11SRW VA14FHB Progeny Massey PGX DH11SRW Pioneer XW15C SY

3 Line (0-100) (Julian) Index VA15W MAS # Pioneer Brand 26R VA09MAS L Armor ARW MBX 16-B MAS # USG MW VA11W MAX Dyna-Gro USG VA09MAS Dyna-Gro AgriMAXX #Turbo SY MAS # VA12FHB CROPLAN SRW MBX 14-S MDX GA E VA14W VA11W Armor ARW #BOSS Progeny DH12SRW Dyna-Gro VA15W VA09MAS VA07MAS NC VA14FHB AgriMAXX VA12W Pioneer Brand 26R WX

4 Line (0-100) (Julian) Index MAS # GAJT E USG AgriMAXX Oakes Pioneer Brand 26R Featherstone Hilliard CROPLAN SRW DH12SRW TN USG SH EXP AgriMAXX DH11SRW L MBX 17-M Pioneer Brand 26R MDX VA09MAS VA09MAS VA15W VA07MAS SY Harrison VA09MAS NC DH11SRW TX EL VA09MAS VA09MAS #Warrior VA11W-108PA VA07MAS VA14W Featherstone VA VA14FHB Armor ARW NC Progeny SH NC

5 Line (0-100) (Julian) Index Armor ARW SY Viper VA09MAS TN VA12W VA09MAS CROPLAN Pioneer Brand 26R Shirley L VA08MAS DH11SRW GA E Progeny VA14W Average LSD (O.05) C.V Released cultivars are shown in bold print. Varieties are ordered by ascending index averages. A plus or minus sign indicates a performance significantly above or below the average. Entries were planted in 2-row plots, 4 ft in length at Mt. Holly, VA and were inoculated at booting stage with scabby corn kernels (50g/4-rows). 1 Scab Incidence : Percentage of infected spikes among 20 randomly selected spikes. 2 Scab Severity : Percentage of infected spikelets among 20 infected spikes. 3 Scab Index = Incidence X Severity/100; it is an overall indicator of scab resistance/susceptibility level. 91

6 Table 32. Two year average summary of reaction of entries in the Virginia Tech State Wheat Tests to Fusarium head blight (scab), 2016 and 2017 harvests. Line FHB Incidence 1 FHB Severity 2 FHB Index 3 (0-100) Rank FHB Index VA13W USG Dyna-Gro MAS # Dyna-Gro AgriMAXX #Bullet VA13W MAS # CROPLAN CROPLAN Progeny MAS # VA12W Massey USG SY SY MBX 16-B L Southern Harvest MAS # Southern Harvest VA12W Dyna-Gro USG VA14FHB MAS # Pioneer Brand 26R VA09MAS VA11W MBX 14-S Dyna-Gro AgriMAXX VA12FHB MAS # Featherstone AgriMAXX VA11W Progeny

7 Table 32. Two year average summary of reaction of entries in the Virginia Tech State Wheat Tests to Fusarium head blight (scab), 2016 and 2017 harvests. Line FHB Incidence 1 FHB Severity 2 FHB Index 3 (0-100) Rank FHB Index VA07MAS Oakes Hilliard VA12W Dyna-Gro Pioneer Brand 26R Pioneer Brand 26R AgriMAXX USG Pioneer Brand 26R VA11W-108PA SY Harrison AgriMAXX DH11SRW SY Viper Featherstone VA VA09MAS VA12W L SH Pioneer Brand 26R VA08MAS Shirley CROPLAN VA14W Average LSD (O.05) C.V Released cultivars are shown in bold print. Varieties are ordered by ascending index averages. A plus or minus sign indicates a performance significantly above or below the average. In 2016, Entries were planted in 2-row plots, 4 ft in length at Blacksburg, VA and were inoculated at 50% and 100% heading stages with Fusarium graminearum spore suspension (50,000 spores/ml). In 2017, Entries were planted in 2-row plots, 4 ft in length at Mt. Holly, VA and were inoculated at booting stage with scabby corn kernels (50g/4-rows). 1 Scab Incidence : Percentage of infected spikes among 10 randomly selected spikes. 2 Scab Severity : Percentage of infected spikelets among 10 infected spikes. 3 Scab Index = Incidence X Severity/100; it is an overall indicator of scab resistance/susceptibility level. 93