MINNESOTA

CEREAL RUST LABORATORY, USDA-ARS

University of Minnesota, 1551 Lindig, St. Paul, MN 55108, USA.

D.L. Long, K.J. Leonard, D.V. McVey, M.E. Hughes, D.H. Casper, and J.J. Roberts.

The rusts of wheat in the United States in 1996.

Stem rust (Puccinia graminis f. sp. tritici). During 1996, wheat stem rust overwintering sites were found in southern Texas, southern Louisiana, and southern Illinois. During the first week in April, traces of stem rust were found in winter wheat fields southwest of Houston and in southern Louisiana. Stem rust development in southern Texas and Louisiana in 1996 was less than in 1993, which was the last year with significant wheat stem rust in the U.S. The year 1993 and other recent years with greater than average stem rust generally had warmer late winter and early spring weather with more rainfall than occurred in 1996. Traces of wheat stem rust were observed on susceptible cultivars in southern and central Texas nurseries in late April.

In early June, traces of stem rust were found in plots and a field in east central Arkansas. During the second week in June, wheat stem rust severities ranged from trace to l % in fields of soft red winter wheat in southern Illinois and plots in central Indiana. Traces of stem rust were found on soft red winter wheat plants throughout southern Wisconsin and southern Michigan in late June. In early July, stem rust severities were light to moderate in south central Wisconsin fields. By late July, severely rusted fields of soft red winter wheat were observed in northwestern Illinois, northeastern Wisconsin and east central Michigan. Statewide, stem rust loss estimates were 3 % in Indiana, 3 % in Illinois, 2 % in Wisconsin, and 2 % in Michigan (Table 1, p. 301). The Indiana loss to stem rust was the most since 1986.

During the second week in June, traces of stem rust were observed in central and northeastern Kansas plots. The first stem rust observation was 2 weeks later than normal for the northeastern Kansas location. During late June, wheat stem rust was found at trace-40 % severities in plots and trace-l % severities in fields of susceptible cultivars in northern Kansas and southern Nebraska. The first stem rust infections in this area occurred when stem rust spore-laden rains fell in early June. The hot, dry weather in mid-June in this area was not conducive for rust increase.

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In mid-July, traces of wheat stem rust were found in plots and fields of winter wheat in southeastern South Dakota and east central North Dakota. At that time, traces of wheat stem rust also were found in plots of the susceptible spring wheat Baart in west central Minnesota, eastern South Dakota, and central North Dakota. A more severe case of wheat stem rust, 20 % severity, was observed on the susceptible spring wheat cultivar Max in a southeastern North Dakota plot. In mid-July, the durum cultivar Mindum, which was released over 50-years ago, had traces of stem rust in plots in east central North Dakota. In an east central South Dakota nursery, some of the late-planted, susceptible, spring wheat cultivars were destroyed by rust by mid-July.

Several factors delayed stem rust development in the central Great Plains. First, stem rust overwintering in the southern plains was less than normal. Second, cool, dry conditions in late winter in the southern plains and hot, dry weather in early June in the central plains were not conducive for rust increase. In spite of this, sufficient quantities of stem rust spores spread from the central Great Plains to initiate stem rust foci in susceptible spring wheat plots in the northern Great Plains. Stem rust from these foci developed normally. The stem rust resistance in the spring wheats remains highly effective in the northern plains. Spring wheats would have suffered significant losses throughout the northern plains without this highly developed stem rust resistance

By mid-July, hot spots (1-20 % stem rust severities) were reported in winter wheat plots in the Palouse area of Washington and a 0.1 % statewide loss was estimated (Table 1, p. 301). Traces of stem rust were found on winter wheat in plots in western New York in mid-July.

Ten Pgt- races were identified from 101 wheat collections made in the U.S. in 1996 (Table 3, p. 304) as compared to six Pgt- races identified from 69 collections in 1995. Race Pgt-TPMK was again the predominant race identified as it was from 1974-89 and 1992-95 and comprised 65 % of the isolates in 1996 compared to 40 % in 1995, 41 % in 1994, 74 % in 1993, 53 % in 1992, and 36 % in 1991. Pgt-QFCS comprised 26 % of the isolates in 1996, 17 % in 1995, 41 % in 1994, 16 % in 1993, 21 % in 1992, and 14 % in 1991. Pgt-QCCJ, the barley attacking race, comprised only 1% of the isolates identified from wheat in 1996 compared to 27 % in 1995, 26 % in 1994, 8 % in 1993, 21 % in 1992, and 14 % in 1991. In wheat in 1996, this race was identified only from collections made from nurseries in Texas and Minnesota.

Wheat leaf rust (Puccinia recondita f. sp. tritici). Southern Plains. Leaf rust overwintered in lesser amounts than normal throughout most of the southern U.S. in 1995-96. During the last week in March, 20 % leaf rust severities were observed on lower leaves of wheat plants in southern Texas fields, and traces were observed in central Texas nursery plots. By late March, leaf rust was generally severe in nursery plots throughout southern Texas and moderate in central Texas, but the cool, dry weather kept the rust in check. Leaf rust severities were lower than normal throughout the southern U.S. by mid-April. Rust was light in southern Texas fields and plots of susceptible cultivars; 40 % severities were observed, which is much less than normal. During the third week in April, no wheat leaf rust was observed in fields and plots in north central Texas. By the first week in May, 30 % rust severities were observed on susceptible cultivars in central Texas nursery plots, and traces were found in north central Texas fields (Fig. 1, p. 302). Traces of leaf rust were found in south central Kansas and north central Oklahoma during the third week in May. Leaf rust development in this area was minimal, because little or no rust overwintered and little rust inoculum arrived from areas farther south where drought conditions existed.

Central Plains. In contrast to the 1994-95 winter, when leaf rust overwintered throughout Kansas, very little rust overwintered in Kansas in 1995-96. In early June, traces of leaf rust were found in plots and fields of susceptible cultivars throughout Kansas (Fig. 1, p. 302). Most of the rust pustules were concentrated on upper leaves indicating that the rust developed from exogenous spore sources. During the third week in June, leaf rust was widespread throughout Kansas on wheat plants where there still was green tissue. Severities ranged from trace-5 % on cultivars in plots and traces in fields in northeastern Kansas. In 1996, the loss estimate in Kansas due to leaf rust was less than 0.1 %, significantly less than the 5 % loss in 1995. During the third week in June, 20-40 % severities were found on susceptible wheat cultivars in east central Nebraska plots. In late June, 40 % leaf rust severities were observed in a few fields and plots of susceptible cultivars in southern Nebraska. Losses varied with local conditions; the final estimated loss for the entire state was 0.5 %.

Northern Plains. On June 28, traces of wheat leaf rust were found in west central Minnesota; east central South Dakota, and Winnipeg, Canada, nurseries. This was 2 weeks later than the normal first date of observation of wheat leaf rust at these three locations. During early July, traces of leaf rust were found in spring wheat plots in central and east central North Dakota and in a winter wheat field in east central North Dakota. In mid-July, trace to 5 % severities were common on flag leaves in plots and fields of winter wheat in east central and eastern South Dakota and southeast North Dakota. Leaf rust severities in the northern plains in 1996 were much lower than normal, because movement of leaf rust from the southern and central plains was also much less than normal. Initial leaf rust infection in the northern plains comes mainly from windborne spores from the south that are deposited with rains on wheat fields. In mid-July, in susceptible spring wheat plots, trace-5 % severities were common, but no leaf rust was observed in the spring wheat fields in the northern Great Plains before August. By early August, in susceptible spring wheat plots, trace-10% severities were common. Due to resistance, only traces of leaf rust developed in commercial fields and, therefore, losses were minimal in spring wheats (Table 2, p. 303). No rust was reported on durum wheat.

Southeast. During late March, in the southeast U.S., leaf rust severities were generally light on susceptible southern soft red winter wheat in plots and fields. By mid-April, wheat leaf rust was severe in nursery plots in southeastern Louisiana and light in plots in the panhandle of Florida. By late April, leaf rust was severe on susceptible cultivars in nurseries and light in fields in central Louisiana and southern Georgia (Fig. 1, p. 302). The winter rainfall in the Florida panhandle and southern Georgia was normal, creating favorable conditions for rust infection. Cool temperatures in February and March slowed rust development, but warm temperatures and moist conditions in early April were favorable for rust buildup. These rust-infected plants provided leaf rust inoculum for wheats farther north. In late April, traces of leaf rust were found in an east central Arkansas field where leaf rust had survived the extremely cold winter. In mid-May, traces of leaf rust were reported in nurseries from east central North Carolina to east central Arkansas.

Midwest. In early June, light leaf rust was observed on soft red winter wheat from eastern Virginia to southern Illinois (Fig. 1, p. 302). In mid-June, trace to 15 % severities were observed in soft red winter wheat fields and nurseries at the soft-dough stage throughout Indiana and Illinois. In the third week in June, traces of leaf rust were observed in fields in the Thumb area and central Michigan. In Michigan, the leaf rust that developed was from spores that were deposited with rain from southern inoculum sources and not overwintering sources. Leaf rust was severe in susceptible cultivars growing throughout Michigan in early July.

California. During the last week in March, 15 % leaf rust severities were reported on fall-sown spring wheat cultivars growing in nurseries and fields in the San Joaquin Valley in California. By the last week in April, moderate to severe leaf rust was found on wheat cultivars growing in nurseries and fields in the San Joaquin Valley. By the first week in May, 60 % leaf rust severities were reported on wheat cultivars growing in nurseries and in some fields in the Sacramento Valley in California. Fields in the Sacramento Valley generally had moderate severities. Leaf rust losses on wheat occurred on the majority of the cultivars throughout the state except for Express and RSI 5, which displayed excellent resistance. The estimated loss due to wheat leaf rust in California was 12 % (Table 1, p. 301).

Northwest. During mid-May, leaf rust was found throughout the state of Washington and the Columbia basin, with 40 % severities being reported on susceptible cultivars in nurseries. This was more severe leaf rust than normal for mid-May. Wheat leaf rust increasied rapidly in early June in the Pacific Northwest. In central Washington, 90 % severities were reported on susceptible cultivars, and in the Palouse area of Washington, leaf rust was light to moderate. There was some spraying to control leaf rust on soft white wheat. An emergency label was obtained for the use of Folicur on wheat in Washington, because supplies of Bayleton ran low. Leaf rust development in eastern Oregon and Washington and northern Idaho was delayed by dry weather during early June, but rains in mid-June allowed for a rapid buildup of leaf rust in winter wheats in late June. Rains in eastern Washington and eastern Oregon during the last week in June created ideal conditions for rust increase, and in mid-July, leaf rust was light to moderate in spring wheat plots. Ideal moisture conditions for rust infection and endogenous rust inoculum created conditions for statewide losses of 1-2 % to leaf rust in the Pacific Northwest,

Northeast. Leaf rust severities ranged from trace to 10 % on winter wheats across the state of New York during the first week in July.

Races identified. In 1996, 31 wheat leaf rust races were identified (Tables 4 and 5, p. 308-309). Four races (MBTB, MBTL, MDJB, and TCRL) were identified for the first time. Race MBRL was the most predominant race identified in 1996 as it also was in 1995 and 1994. MBRL comprised 38 % of the isolates in 1996 compared to 28 % in 1995, 36 % in 1994, and 6 % in 1993. Race MBGL, the most frequently identified race from 1989-93 comprised 6 % of the isolates in 1996, 21 % in 1995, 16 % in 1994, and 20 % in 1993. Twenty-nine Prt-races comprised the other 56 % of the U.S. population in 1996.

Wheat stripe rust. (Puccinia striiformis). By the second week in April, moderate severities of wheat stripe rust were observed in the San Joaquin Valley and traces were found in the Sacramento Valley of California. Traces of wheat stripe rust were found in wheat fields in the Sacramento Valley during early May.

By early May, wheat stripe rust was found throughout the state of Washington where environmental conditions were ideal for rust development. Sixty percent severities were reported on susceptible cultivars in western Washington plots, and 10 % severities in eastern Washington plots. The earliest planted fields of HRWW in central Washington were sprayed in early May for stripe rust control. By the third week in May, stripe rust was widespread throughout the Pacific Northwest and increased to epidemic levels on susceptible cultivars. The moist, cool conditions this spring were ideal for rust development. By early June, wheat stripe rust was increasing. Stripe rust was found on spring wheats, but cultivars with adult plant resistance were not seriously damaged. Growers used large amounts of fungicide to control stripe rust on the susceptible hard red and club wheat cultivars. Dry weather during the first 2 weeks of June delayed stripe rust development in eastern Oregon and Washington and northern Idaho. During early July, rust buildup on the soft white wheats was light, because most of the major cultivars are resistant to stripe rust. In early July, stripe rust was severe in plots of susceptible winter wheat in the Palouse area of Washington, but stripe rust was not a problem in commercial fields with adult plant resistance. However, a 2 % stripe rust loss was estimated in the state of Washington. Stripe rust in the Pacific Northwest was severe this year, and losses were greater than last year.

In early July, light amounts of stripe rust were detected in the Gallatin Valley in Montana, but hot, dry weather prevented further increase. No wheat stripe rust was found in the central U.S. this year.

Losses due to rust. Acreage harvested and yield production records based on 1996 Crop Production Summary, Agricultural Statistics Board, USDA. Loss data are summaries of estimates made by personnel of the State Departments of Agriculture, University extension and research projects, Agricultural Research Service, USDA, and the Cereal Rust Laboratory.

Losses were calculated for each rust as follows:

Loss (specific rust) = (Production) X (Percent loss)

(100%) - (Percent loss due to rusts)

Losses were indicated as a trace when the disease was present but no fields were known to have suffered significant losses. When a few fields suffered measurable losses, this was reflected as a percent of the state's production. Zeros indicate that the disease was not reported in that state during the season. Blanks for stripe rust indicate that the disease was not reported and does not occur annually in that state. Trace amounts were not included in the calculation of totals and averages.

Table 4. Prt code and corresponding virulence formula for wheat

leaf rust collections made in 1996.

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Prt codea Virulence formulab

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LBBQ 1,10,18

MBBB 1,3

MBBL 1,3,10

MBDL 1,3,10,17

MBGL 1,3,10,11

MBGQ 1,3,10,11,18

MBRL 1,3,3ka,10,11,30

MBRQ 1,3,3ka,10,11,18,30

MBTB 1,3,3ka,11,17,30

MBTL 1,3,3ka,10,11,17,30

MCBL 1,3,10,26

MCDL 1,3,10,17,26

MCGL 1,3,10,11,26

MCRL 1,3,3ka,10,11,26,30

MDBL 1,3,10,24

MDGL 1,3,10,11,24

MDJB 1,3,11,17,24

MDRL 1,3,3ka,10,11,24,30

MFBL 1,3,10,24,26

MGBL 1,3,10,16

PBDL 1,2c,3,10,17

PBMQ 1,2c,3,3ka,10,18,30

PNMQ 1,2c,3,3ka,9,10,18,24,30

TBBL 1,2a,2c,3,10

TBGL 1,2a,2c,3,10,11

TCBG 1,2a,2c,3,18,26

TCRL 1,2a,2c,3,3ka,10,17,26,30

TDBL 1,2a,2c,3,10,24

TDGL 1,2a,2c,3,10,11,24

TFGL 1,2a,2c,3,10,11,24,26

TLGG 1,2a,2c,3,9,11,18

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a Prt code plus Lr10 and 18 near-isogenic supplementals, after

Long and Kolmer, Phytopathology 79:525-529.

b Resistances evaluated:

Lr1, 2a, 2c, 3, 9, 16, 24, 26, 3ka, 11, 17, 30, 10 and 18.

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USDA-ARS and Department of Agronomy and Plant Genetics.

University of Minnesota, St. Paul, MN 55108, USA.

Wheat production, breeding, and scab screening.

R.H. Busch, Charles Hu, and Ruth Dill-Macky.

Minnesota produced an estimated 101 million bushels (3.4 million metric tons) from 2.4 million acres (0.92 million hectares) in 1996. An average yield of spring wheat in 1996 was 42 bu/acre, compared to 32 bu/acre in 1995 and 28 bu/acre in 1994. FHB has been very severe in the 1990s, with severe attacks beginning in 1990 and 1991 and devastating attacks in 1993 and 1994. Severe FHB epidemics continued in 1995, but finally in 1996, a much smaller area was attacked. Many of the more popular and newer varieties were susceptible to FHB. Pioneer 2375 was the most tolerant variety to FHB and has remained our most popular variety. Most newly released varieties now have some tolerance and may outyield 2375, but it remains one of the most tolerant varieties.

The type of resistance is important for FHB, because there is no known immunity. If infected, all genotypes of wheat show the infection site. Those with high resistance to spread, Type 2 resistance, will restrict the spread to no more than that floret or spikelet. Type 1 resistance measures the ability of the fungus to infect the floret and is referred to as incidence (% of spikes infected). Type 3 is resistance of the kernel to effects of FHB infection. 2375, Sharp, and Butte 86 tend to display this type of resistance. Type 4 is detoxification of DON, whereas Type 5 was defined as resistance to yield loss. We are basically evaluating Types 1, 2, and 3. DON evaluation is too expensive at present. Type 5 is ability to maintain yield when infected still and is difficult to measure, but Dr. John Wiersma is attempting to develop a test at the Northwest Experiment Station at Crookston, MN.

Screening for FHB resistance takes several steps in our program for assessment. First, the new materials are tested in the greenhouse for resistance to spread (Type 2). We conduct three greenhouse screens per year. Lines that exhibit at least a moderately resistant reaction are then planted into a misted and inoculated FHB nursery at St. Paul, which is managed by J. Groth, plant pathologist. The materials are evaluated for both Type 1 and 2 resistances, and then we harvest and assess the grain for Type 3. `Genotype x environment' interactions have been observed, but if a line is susceptible, it is easily discarded. Those lines that exhibit moderate resistance give the most interaction. Lines with high spread resistance, primarily from Asian sources, seem to provide more stability to various environments, but the Asian sources do not appear to provide Type 3 resistance to the level of 2375 or Sharp. We have seen the Asian sources of resistance succumb to FHB and feel that incorporation of Type 3 resistance is important for stable production under disease epidemics.

Obviously, many potential sources of resistance to FHB have been screened. In 1994-95, we screened 80 Chinese winter wheats for Type 2 resistance (Table 1). A summary of their reactions to multiple screens in the greenhouse is provided and simplified into a rating system: R = resistant, MR = moderately resistant, MS = moderately susceptible and S = susceptible. The ratings are defined as: R = no spread 20 days after inoculation; MR = disease spread to the adjacent 1 to 2 spikelets in 20 days; MS = disease spread to one-half of the adjacent spikelets in 20 days; and S = spike was killed in 20 days or before. Three varieties were resistant, Yumai 7, Yanshi 9, and Ermai 9, all are marked in bold. However, Yanshi 9 and Ermai 9 appear to be the same variety. Their reaction was the same as that of Sumai #3, which is the most resistant variety in greenhouse testing. All greenhouse screening is conducted using four sources of inoculum collected from the field around the state of Minnesota. At least 30 isolates from these sources of Fusarium were mixed, and after preparing the inoculum using mung bean soup, plants were inoculated at anthesis using a micropipet with 2 [micro]l of inoculum. Plants were placed in a dew chamber at 20 C and 16 h daylight.

Table 1. Scab reaction of Chinese winter wheats, in greenhouse tests, USDA-ARS and University of

Minnesota.

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Cultivar Evaluation Cultivar Evaluation Cultivar Evaluation

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Annong 8903 S Linfen 7203 S Wannian 2 MR

Aiganzao S Longmai 8 S Wanxiu 8802 S

Bainong 62 S Lumai 1 S Xianyan 6 MS

Baiquan 3039 S Lumai 3 S Xuzhou 21 S

Baiquan 3217 S Lumai 5 S Xuzhou 174 S

Baofeng 7228 MR Lumai 7 S Xuzhou 319 S

Boai 7023 MS Lumai 8 S Xuzhou 504 MS

Beijing 10 S Machang 2 MR Xuzhou 8697 S

Beijing 837 MS Mazhamai S Xuzhou 8785 S

Beijing 411 S Mianyang 11 S Xuzhou 8876 MS

Beijing 841 S Neixiang 5 S Xuzhou 8913 S

EastChina 6 (W) S Neixiang 182 S Yangmai 3 MR

EastChina 6 (S) S Nongda 139 MS Yangmai 5 MS

Ermai 1 S Nongda 311 MS Yannong 15 S

Ermai 9 R Nongda 84015 S Yanshi 86(117) MS

Fan 6 MS Pimai 90 S Yanshi 9 R

Fengkong 8 MR Pingyang 27 S Yimai 7 S

Fengkong 13 MS Pingyuan 50 MS Yumai 2 S

Ganmai 8 S Qinmai 3 S Yumai 7 R

Huaiyin 894 S Shan 29 S Yuzhimai S

Ji 21 S Shan 167-6 MS Zhengyin 1 MR

Ji 30 S Shan 229 MS Zhengzhou 831 S

Ji 31 S Shan 757 S Zhengzhou 891 MS

Ji 37 S Shan 7859 S Zhengzhou 8329 MR

Jimai 2148 S Shandong 912649 S Zhengzhou 79201 S

Jinan 13 S Shandong 921842 S Zhong 4 MS

Jingan 908 S Shi 865144 MR Zhoumai 8 MS

Jingan 5042 MS Shi 90-4005 S Zhoumai 10 MS

Laizhou 1-8 S Sumai 3 R Zhongliang 12S

Laizhou 953 MS Taishan 1 S Wheaton (check) S

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Note: Tested in spring and summer, 1994. Evaluation of resistance by statistic analysis. Infection

scale based on conversion of numerical data to a R (resistance), MR (moderate resistance), MS (moderate

suscep tible), and S (susceptible). R indicates very low average spread.

A field screening nursery for FHB was initiated at Minnesota in 1986, and useful data were obtained to allow crossing of more resistant Asian varieties with adapted spring wheats beginning in 1988. Pioneer also made crosses beginning in 1988-89 for scab resistance. When Pioneer closed the spring wheat program, the germplasm was distributed to Minnesota and North and South Dakota. This distribution of germplasm has been quite valuable, and Pioneer is highly commended. Screening in the inoculated nursery of Pioneer material, germplasm from CIMMYT's Paraguayan program (Bekele), and Minnesota was initiated in 1992-93. Naturally occurring FHB had been used only in selection in the early generation, 1990-91. Greenhouse screening was not initiated until 1994, when Charles Hu began developing the many details needed to obtain adequate greenhouse testing for Type 2 resistance. The Minnesota Wheat Research and Promotion Council provided a small emergency grant to allow greenhouse testing to begin. The Council was made aware of FHB as a potential problem and began funding some FHB research in the mid-1980s.

Table 2. Scab reaction of Triticum tauschii-derived synthetic hexaploid lines from CIMMYT, in greenhouse tests, USDA-ARS and University of Minnesota. Evaluation of resistance by # of Resistant/Susceptible plants where

R = No susceptible plants, MR = 1 susceptible plant, MS = 2 susceptible plants, S = 3-5 susceptible plants, and

HS = susceptible, but dead in 20 days.

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Entry # R/S Evaluation Entry # R/S Evaluation Entry #R/S Evaluation

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TA2901.00 0/5 HS TA4066.03 3/2 MS TA4084.20 0/6 S

TA2902.00 0/5 HS TA4064.20 0/6 S TA4084.30 0/7 S

TA2903.00 2/3 S TA4065.10 3/3 S TA4084.40 0/2 S

TA2904.00 0/7 S TA4065.20 0/3 S TA4084.50 1/6 S

TA2906.00 1/4 S TA4066.01 5/2 MS TA4085.00 0/5 S

TA2907.00 0/3 HS TA4066.02 3/2 MS TA4086.00 2/2 MS

TA2970.00 0/4 S TA4066.03 3/2 MS TA4087.00 1/5 S

TA4041.00 4/1 MR TA4066.05 2/3 S TA4088.00 0/3 S

TA4042.00 1/5 S TA4066.06 1/3 S TA4089.00 2/4 S

TA4043.00 0/7 S TA4066.07 1/6 S TA4090.0 --

TA4044.00 3/3 S TA4066.08 -- TA4091.00 1/4 S

TA4045.00 0/5 S TA4066.09 0/5 S TA4094.10 3/2 S

TA4046.00 1/3 S TA4066.10 0/5 S TA4094.20 1/2 MS

TA4047.00 1/5 S TA4067.00 1/4 S TA4094.30 1/4 S

TA4048.00 0/6 S TA4068.00 0/6 S TA4095.01 0/5 S

TA4049.00 0/6 S TA4069.00 1/4 S TA4095.02 1/5 S

TA4051.00 2/1 MR TA4070.00 0/1 S TA4095.05 0/5 HS

TA4052.00 1/3 S TA4071.00 0/4 S TA4095.07 1/3 S

TA4053.10 3/4 S TA4072.00 0/5 S TA4095.08 2/3 S

TA4053.20 2/3 S TA4073.20 2/3 S TA4095.09 0/2 S

TA4054.10 2/1 MR TA4073.30 4/3 S TA4095.10 0/5 S

TA4054.20 3/2 MS TA4074.10 0/2 S TA4095.11 0/5 S

TA4055.00 2/2 MS TA4075.10 1/3 S TA4096.00 0/4 S

TA4056.10 3/2 MS TA4075.20 2/3 S TA4097.20 2/2 MS

TA4056.20 -- TA4075.30 1/4 S TA4097.30 0/3 S

TA4057.10 -- TA4075.40 0/3 S TA4098.00 0/5 S

TA4057.20 0/5 S TA4075.50 2/5 S TA4099.00 0/7 HS

TA4058.00 1/4 S TA4077.00 1/5 S TA4100.00 0/5 S

TA4059.00 2/5 S TA4078.00 0/3 S TA4101.00 0/3 S

TA4060.00 2/1 MR TA4080.01 0/2 S TA4102.00 1/5 S

TA4061.00 0/4 S TA4080.02 0/6 S TA4103.00 0/5 S

TA4062.00 0/5 S TA4080.03 0/9 S TA4104.00 0/6 S

TA4063.20 4/2 MS TA4080.04 5/1 MR TA4105.00 0/5 S

TA4063.30 2/2 MS TA4080.05 1/3 S TA4106.00 0/5 S

TA4063.40 0/5 S TA4080.06 0/7 S TA4107.00 0/5 S

TA4064.10 0/5 HS TA4080.10 0/4 HS TA4108.00 0/2 S

TA4064.20 0/6 S TA4081.00 0/2 S TA4109.00 0/3 S

TA4065.10 3/3 S TA4082.00 2/2 MS TA4110.00 0/3 S

TA4065.20 0/3 S TA4083.10 2/5 S TA4111.00 0/5 S

TA4066.01 5/2 MS TA4084.10 1/3 S TA4113.00 0/5 S

TA4066.02 3/2 MS

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BacUp (MN2535) was released in 1996 as an emergency special wheat with high tolerance to FHB. It has high tolerance to spread, low incidence, and good kernels under severe epidemics. Unfortunately, as the name implies, it has low yield with lodging potential, so we suggest that it not be planted on over 15-20 % of the acreage. BacUp has high grain volume weight, very high protein content (17 % average in 1996), and good mixing traits, but grain and texture of the baked loaf is somewhat open. BacUp is not shattering susceptible, which has been a major problem in using the Asian sources of FHB resistance.

Approximately 100 T. tauschii-derived synthetic hexaploid from CIMMYT were tested for Type 2 resistance to scab. These materials were shared with us by Mujeeb Kazi, CIMMYT, and John Raupp of Kansas State University. The test results are given in Table 2. None of the substitution lines had as high level of Type 2 resistance as Sumai #3 (R).

A large cooperative effort in the Upper Midwest to control FHB has been ongoing since 1994. A Uniform Scab Nursery was initiated in 1995 with inoculated and sites (most with misting) at St. Paul and Morris, MN; Prosper and Langdon, ND; Glen Lea, Manitoba, Canada; and Brookings, SD. A report is provided and is public information. Any seed of the Chinese winter wheats is also available on request. Contact Robert Busch, USDA-ARS, 411 Borlaug Hall, 1991 Buford Circle, Univ. of Minnesota, St. Paul, MN 55108, FAX: 612-625-1975; E-mail: busch005@maroon.tc.umn.edu.


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