Section 5: Wheat Scab Research

Transcription

1 67 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 () or scab. Each year all wheat entries in Virginia s Official State Variety Trials are evaluated for resistance in an inoculated, irrigated nursery at the Blacksburg test site. Data from this test for the current crop year and two- and three-year averages for incidence, severity and (incidence x severity / 100) are included in this bulletin (Tables 38 40) to aid producers in selection of cultivars on the basis of resistance. Cultivars possessing complete resistance or immunity to 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 resistance into cultivars to enhance the overall level of resistance. Genes controlling 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 incidence, severity, and DON toxin content. Incorporating such multiple resistance genes having additive effects on 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, 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. Entries were inoculated by spraying a Fusarium graminearum spore suspension directly onto spikes at the 80% flowering stage. A normal infection level was obtained in Among 83 lines and varieties tested in 2010, the index varied from 1% to 27% with incidence ranging from 8% to 48% and severity ranging from 5% to 50% (Table 38). Twenty one lines and 35 varieties had index values lower than the mean (<5%) and expressed moderate resistant to in Based on two year mean data for 2009 and 2010 (Table 39), eight lines and 25 varieties had index values lower than the test mean (<9%). Five experimental lines and 15 varieties tested across three years ( ) had average index values lower than the test mean of 12% (Table 40). Varieties expressing resistance to based on three-year mean data are: Dominion, Progeny 166, USG3315, Massey, Coker 9553, Jamestown, USG 3665, Branson, Progeny 117, SS-MPV57, SS 8302, Coker9804, USG 3555, Progeny 185, SS 8309, Pioneer 26R15.

2 68 Table 38. Summary of reaction of entries in the Virginia Tech State Wheat Test to Fusarium head blight (scab) and glume blotch resistance, 2010 harvest. 3 VA07W USG Pioneer 25R VA08W USG VA07W VA06W VA06W SS SS VA06W USG VA08W Dominion VA08W VA05W VA08W SS SS VA07W VA07W Massey Progeny NC Dyna Gro SS-MPV SS SY Panola VA05W USG VA06W Branson W VA08W GA E USG SS GA E COKER Vigoro V Pioneer 26R Renwood USG

3 69 Table 38. Summary of reaction of entries in the Virginia Tech State Wheat Test to Fusarium head blight (scab) and glume blotch resistance, 2010 harvest, continued. 3 USG VA08W GA E Vigoro Shirley VA06W Pioneer 26R Coker NC-Cape Fear Jamestown VA05W Progeny VA07W SS Pioneer 26R VA06W VA08W Progeny VA06W VA05W VA05W USG Oakes VA08W SS MD00W VA06W VA06W VA08W NC-Yadkin VA08W VA05W SS Chesapeake Pioneer 26R VA05W

4 70 Table 38. Summary of reaction of entries in the Virginia Tech State Wheat Test to Fusarium head blight (scab) and glume blotch resistance, 2010 harvest, continued. 3 Pioneer 26R Merl Featherstone Average LSD (0.05) 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 Blacksburg, VA and were inoculated at 50% and 100% heading stages with Fusarium graminearum spore suspension (50,000 spores/ml). 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 = Incidence X Severity/100; it is an overall indicator of scab resistance/susceptibility level.

5 71 Table 39. Two year average summary of reaction of entries in the Virginia Tech State Wheat Tests to Fusarium head blight (scab) and glume blotch resistance, 2009 and 2010 harvests. 3 VA06W SS Pioneer 25R COKER Vigoro V Dominion Coker USG Progeny VA06W SS Jamestown Massey SS Oakes USG SS VA05W VA05W Branson VA06W VA05W NC-Cape Fear USG SS VA05W Progeny NC-Yadkin Progeny USG

6 72 Table 39. Two year average summary of reaction of entries in the Virginia Tech State Wheat Tests to Fusarium head blight (scab) and glume blotch resistance, 2009 and 2010 harvests, continued. 3 Vigoro VA07W Panola Pioneer 26R VA07W SS-MPV VA06W Renwood Pioneer 26R Pioneer 26R VA06W VA06W VA05W VA05W Shirley Pioneer 26R GA E Merl USG Chesapeake Featherstone Average LSD (0.05) 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 Blacksburg, VA and were inoculated at 50% and 100% heading stages with Fusarium graminearum spore suspension (50,000 spores/ml). 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 = Incidence X Severity/100; it is an overall indicator of scab resistance/susceptibility level.

7 73 Table 40. Three year average summary of reaction of entries in the Virginia Tech State Wheat Tests to Fusarium head blight (scab) and glume blotch resistance, harvests. 3 Dominion Progeny USG Massey COKER Jamestown USG VA05W VA06W VA06W Branson Progeny SS-MPV SS Coker USG Progeny SS VA05W Pioneer 26R VA05W VA05W VA06W SS Pioneer 26R Renwood SS VA05W Pioneer 26R Panola Shirley Merl

8 Table 40. Three year average summary of reaction of entries in the Virginia Tech State Wheat Tests to Fusarium head blight (scab) and glume blotch resistance, harvests, continued. 74 SS Featherstone Chesapeake USG Average LSD (0.05) 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 Blacksburg, VA and were inoculated at 50% and 100% heading stages with Fusarium graminearum spore suspension (50,000 spores/ml). 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 = Incidence X Severity/100; it is an overall indicator of scab resistance/susceptibility level.