Published online 18 May 2006
Published in Crop Sci 46:1622-1629 (2006)
© 2006 Crop Science Society of America
677 S. Segoe Rd., Madison, WI 53711 USA
PLANT GENETIC RESOURCES
Geographic Distribution of Common and Dwarf Bunt Resistance in Landraces of Triticum aestivum subsp. aestivum
J. Michael Bonmana,*,
Harold E. Bockelmana,
Blair J. Goatesa,
Don E. Oberta,
Patrick E. McGuireb,
Calvin O. Qualsetb and
Robert J. Hijmansc
a USDA-ARS, Small Grains and Potato Germplasm Research Unit, 1691 South 2700 West, Aberdeen, ID 83210
b Genetic Resources Conservation Program, University of California, One Shields Avenue, Davis CA 95616
c International Rice Research Institute, DAPO Box 7777, Metro Manila, Philippines
* Corresponding author (mbonman{at}uidaho.edu)
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ABSTRACT
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Landrace accessions of wheat (Triticum aestivum L. subsp. aestivum) from the USDA-ARS National Small Grains Collection (NSGC) have been tested systematically for the past 25 yr for disease resistance. We analyzed the resistance of 10 759 common wheat accessions to common bunt (CB) caused by Tilletia tritici (Bjerk.) Wint. and T. laevis Kühn, and 8167 to dwarf bunt (DB) caused by T. controversa Kühn with respect to geographic origin, relationship to color of awn, glume, and kernel of accessions, and phenotypic variation within areas of high frequency of resistance. A clear center of concentration was evident for CB resistance extending from Serbia and Montenegro through Macedonia, Turkey, and Iran with the highest frequency of resistance occurring in Kosovo province in Serbia and Montenegro (36%) and Bakhtaran province in Iran (40.8%). Compared to CB resistance (5.5% of total tested), DB resistance was more rare (1.3% of total tested). DB resistance was concentrated in accessions from Iran, Turkey, and Serbia and Montenegro with the highest frequency (58%) occurring in Hakkari province in southeastern Turkey. CB resistance was positively associated with lightly pigmented kernels and negatively associated with lightly pigmented awns and glumes. Analysis of accessions from areas with unusually high frequency of resistance suggested that DB resistant accessions from Hakkari are genetically diverse, whereas CB resistant accessions from Bakhtaran may be much less so.
Abbreviations: CB, common bunt • DB, dwarf bunt • GRIN, Germplasm Resources Information Network • NSGC, National Small Grains Collection
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INTRODUCTION
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BUNT and other smut diseases have probably been associated with wheat cultivation since the crop's domestication (Fischer and Holton, 1957). Common bunt occurs on both spring and winter wheat worldwide and DB is found on winter wheat in regions with persistent snow cover (Goates and Peterson, 1999). Although chemical seed treatments can effectively control these diseases, especially CB, resistant cultivars remain desirable for bunt management in developing countries (Saari et al., 1996), for organic production of wheat, and as a lower-cost alternative to chemical treatment. The fungi causing DB and CB are closely related and resistance to both diseases is conferred by the same 15 major resistance genes (Goates, 1996).
During the past 100 yr the USDA has acquired more than 54 454 accessions of cultivated wheat and wild relatives of wheat, including 19 615 landrace accessions of common wheat. Systematic characterization of the collection began about 25 yr ago and some disease and insect resistance evaluations began even earlier. Also, many of the accessions have been characterized for various agronomic, spike, kernel, and quality traits. Since the evaluation program began, many of the common wheat accessions in the NSGC have been tested for resistance to CB and DB, including 97% of the landrace accessions present in the collection. This compilation represents one of the most complete sets of disease evaluation data collected by the NSGC. The data can be accessed through the USDA-ARS Germplasm Resources Information Network (GRIN) database at www.ars-grin.gov/npgs. The purposes of the present research were to (i) analyze the NSGC data for CB and DB resistance among common wheat landrace accessions to elucidate relationships between resistance and other characteristics, including geographic origin and awn, glume, and kernel color and (ii) generate information to guide future wheat acquisition, evaluation, and utilization.
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MATERIALS AND METHODS
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Disease Resistance Assessment
Landrace accessions of common wheat from the NSGC were tested for CB reaction at Pendleton, OR from 1981 to 1986 by R.J. Metzger and at Aberdeen, ID from 1992 to 2004 by B.J. Goates. A total of 4478 accessions were tested at Pendelton and 9177 were tested at Aberdeen. Several thousand accessions were tested in more than one experiment and for these the highest disease score was used, resulting in 10 759 accessions in the analysis of CB resistance. Seeds were heavily surface-inoculated with teliospores of the CB pathogens before planting 4 to 7 cm deep in single 1.5 m rows when soil temperatures were 5 to 10° C (Goates, 1996). In the tests in Pendleton during 1982 and 1984 specific accessions were inoculated with one of three pathogenic races, and in 1985 and 1986 specific accessions were inoculated with a single race or a race composite. In Aberdeen during 1992 to 2004 one of three different race composites were used separately in different years to represent a broad spectrum of virulence. Specific information on the pathogenic race, race composite, the virulence genes contained in each race, and the inoculum used in each experiment is available on GRIN.
For DB, 8167 landrace accessions were tested near Logan, UT, from 1978 to 2005. Seeds were sown about 2 cm deep in a furrow 8 to 10 cm deep, timed so that plants were at the 2- to 3-leaf stage before the onset of dormancy in late fall (Goates, 1996). Inoculum was applied onto the soil after planting as a water suspension at a rate of about 0.25 g of teliospores per row. The inoculum was prepared by suspending ground bunted spikes in water and filtering the resulting teliospores suspension through cheesecloth. The inoculum was a composite of all named T. controversa races and other isolates from throughout the western US. The composite is maintained by periodically adding races to inoculum for the nursery, and then harvesting smutted spikes from both resistant and susceptible genotypes.
For both diseases the number of bunted and healthy spikes per row was scored after physiologic maturity, growth stage 92 (Zadoks et al., 1974), then recorded in GRIN as a percentage relative to the susceptible checks, cultivars Red Bobs for CB, and Cheyenne for DB, which were sown every 20 rows throughout the nurseries. Trials where the susceptible checks showed less than 70% infection were not used. These data and other accession level data were extracted from the GRIN for this report.
Agronomic Descriptor Data
Nearly all of the landrace accessions in the NSGC have been scored for growth habit based on spring-sown evaluations at Aberdeen, ID (43°2' N, 112°49' W, 1331 m elevation). Accessions flowering normally were designated as having spring habit, those that did not flower as having winter habit, and those that flowered very late as facultative. Most of the accessions tested in the CB nurseries had spring habit and most of those tested in the DB nurseries were classified as winter habit. Using color charts and standard rating codes, about 6000 landrace accessions have been scored for awn and glume color and more than 8000 have been scored for kernel color. Landrace classification was determined by the NSGC curator (H.E. Bockelman) based on information available in the passport data and is somewhat subjective.
In addition to the information from the GRIN database, we used information for most of the Iranian accessions from field experiments done at the University of California Davis Agronomy Research Farm (38° 32' N, 121° 46' W, 16 m elevation) from 1991 to 1996. These accessions were received by C.O. Qualset from the University of Tehran from 1986 to 1989 and represent 90% of the Iranian landrace accessions within the NSGC. Plantings were made in November or December each year. Irrigation was applied when needed, usually two times each year during pre- and post-heading. Accessions were sown in single 2.5-m rows spaced 60 cm apart laid out 20 rows wide in a serpentine pattern with spring habit check cultivars Yecora Rojo and Anza repeated throughout the experiment. Data were obtained for: days to heading and maturity (expressed as days past 31 March); flag leaf blade length and width (cm, two leaves for each accession); mature plant height (cm); spike length (mm) measured as the distance from the tip of the apical spike to the collar; awn length (mm); number of spikelets per spike; and kernel weight (mg kernel–1) based on 50 kernels. Awn, glume, and kernel color were also recorded.
Data Analysis
Accessions were classified as resistant if 5% or less disease incidence relative to the susceptible check was recorded. Countries of origin were classified into regions based on the United Nations designations for World Macroregions (United Nations, 2000). Nonoverlap of the 95 or 99% binomial confidence intervals was used as a basis for determining significant differences between accessions from various geographic groupings.
Sites of collection for individual wheat accessions were georeferenced by one of the following methods based on the level of detail available in the locality data: (1) collector notes indicating geographic coordinates (latitude and longitude) based on maps or GPS instruments; (2) gazetteers either from the GEOnet Names Server (National Geospatial-Intelligence Agency, 2004) or the Getty Thesaurus of Geographic Names Online (J. Paul Getty Trust, 2000) when the collection site was named; or (3) ArcView 8.2 (ESRI, 2002) software when collector's notes indicated distance and direction from a city or village or other landmark. We obtained coordinates for a total of 7727 accessions tested for CB resistance and 6094 accessions tested for DB resistance. Accessions that lacked specific locality or coordinates were mapped either to state/province or to country level only and these data were used in analyses that did not require identification of the specific collection site. Elevation data were derived from either collector notes indicating elevation or the GTOPO30 dataset on the Global GIS Global Coverage DVD developed by the U.S. Geological Survey and the American Geological Society (Hearn et al., 2003). DIVA-GIS 5.2 was used to determine the fraction of the accessions that were resistant in 100- by 100-km grid cells (Hijmans et al., 2005b). DIVA-GIS was also used to extract climate data for all accessions from the WorldClim database (Hijmans et al., 2005a).
Not all disease resistance and other descriptor data were available in GRIN for each accession, so associations of CB or DB resistance to awn, glume, and kernel color were assessed on subsets where data for both traits were available. Because few NSGC descriptor data were available within GRIN for Iranian landraces, data collected from UC Davis were used to test for associations between disease resistance with awn, glume, and kernel color. To simplify the analysis color data were classified as either lightly pigmented (white, amber, or yellow) or pigmented (brown, bronze, tan, or red). Data from 1932 to 4797 accessions were available for analysis for each disease-trait combination. Fisher's Exact Test was used to ascertain if there was a relationship between pairs of variables (Langsrud, 2004).
Accessions from certain geographic locations showed unusually high frequencies of resistance. To compare the morphological variation among resistant accessions from these locations with that of other accessions, NSGC data were used for DB and 1991 UC Davis data were used for CB. The NSGC data consisted of images of spikes and kernels captured with a color flat-bed scanner and accessible via GRIN. The 1991 field planting at UC Davis included 248 accessions from Bakhtaran province in Iran and 1858 accessions from other areas of Iran. Values for the quantitative traits measured in the trial were adjusted with Agrobase software (Agronomix Software, 2004) using the quadratic method of moving means. This method adjusts entry values based on the check means and two adjacent rows on either side of the entry. In the case of unbordered end rows, the adjacent four rows on the existing side were used to adjust the entry value. A one-tailed F-test was used to compare variances for the measured traits of the CB-susceptible and resistant accessions from Bakhtaran and other common wheat accessions from throughout Iran that were included in the trial.
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RESULTS AND DISCUSSION
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Relationship to Geographic Origin
General Distribution
Three macroregions, Southern Europe, Western Asia, and South-central Asia, had a significantly higher (P < 0.01) frequency of both CB- and DB-resistant landrace accessions compared to the total for all other regions (Table 1). The frequencies of CB-resistant accessions from South-central Asia, Southern Europe, and Western Asia were 6.9, 6.7, and 7.9%, respectively. The frequency of CB-resistant accessions from elsewhere (0.4%, n = 2485) was significantly less (P < 0.01). Similarly, the frequencies of DB-resistant accessions from South-central Asia, Southern Europe, and Western Asia were 1.2, 0.7, and 5.3%, respectively. No DB-resistant accessions from elsewhere were found (n = 1472). Accessions from South-central Asia, Southern Europe, and Western Asia accounted for 97.8% of the CB-resistant accessions and all of the DB-resistant accessions identified within the collection. Table 2 shows that four of the 40 countries within these three regions (Serbia and Montenegro, Macedonia, Turkey, and Iran) accounted for 92% of the CB-resistant accessions identified, while Serbia and Montenegro, Turkey, and Iran accounted for all of the identified DB-resistant accessions. Serbia and Montenegro had the highest frequency of CB resistance and Turkey had the highest frequency of DB resistance.
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Table 1. Numbers of accessions of common wheat tested and resistant to common and dwarf bunt from nine geographic regions .
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Table 2. Numbers of accessions of common wheat tested and resistant to common and dwarf bunt from four countries and from all other countries.
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Common Bunt Resistance
There is a nearly contiguous geographic band with high frequency of CB resistance from southern Serbia and Montenegro through Iran (Fig. 1A) and this area represents a "center of concentration" sensu Ward (1962) for CB resistance. Most of Bulgaria and a small part of northeastern Greece lie between Macedonia and Turkey (Fig. 1B), but only 76 spring-habit landrace accessions from Bulgaria and Greece were available in the NSGC. Sixty-five of these accessions were tested for CB resistance, none were resistant and few of the accessions had sufficient information to map their origin to a specific geographic point (Fig. 1B). At least one landrace from Greece, PI 116301, is reported to have CB resistance gene Bt10 (Metzger and Silbaugh, 1971), but was susceptible to the races used in NSGC testing and to race X-1 from the Pacific Northwest of the USA (Metzger and Kendrick, 1967). Landrace accessions identified within the GRIN database are generally accessions from farmers' fields or markets collected either before the era of modern plant breeding or in less favorable environments where modern cultivars are not grown. The status of certain other accessions is ambiguous, because the passport data are limited. Seven of 49 such ambiguous accessions from Greece and five of 16 such accessions from Bulgaria were resistant to CB. This frequency of resistance is significantly higher (P < 0.01) than that found within the remainder of the 2167 common wheat accessions in the NSGC that have limited passport data (n = 2167, 1.9% resistant). Based on these observations and on the geographic distribution of resistant landrace accessions, we hypothesize that Bulgaria and northeastern Greece are likely within the center of concentration for CB resistance. The European Wheat Database lists 162 landraces of common wheat from Bulgaria and 137 from Greece (Faberova et al., 2005), and additional sources of CB resistance might be present among these accessions.
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Fig. 1. Specific geographic locations where CB resistant and susceptible wheat landrace accessions were collected: A) pattern of occurrence from Europe through Eastern Asia and B) number of resistant accessions and frequency of resistance per 100 km by 100 km grid cell in the four country region where the most resistant accessions were found.
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Over the four-country center of concentration for CB resistance the frequency of resistant accessions was approximately 11% and within this center there are regions where the frequency of CB resistant accessions is much higher than the average. In Iran the frequency of CB resistance among accessions originating from Bakhtaran province is 40.8% (n = 341) (Fig. 1B) and the adjacent province of Hamadan also has a high frequency of CB resistant accessions (25%, n = 100). In fact, there appears to be a gradient of CB resistant accessions centering on Bakhtaran province with lower frequency as distance from the province increased (Fig. 1B). In Turkey and Macedonia there do not appear to be any subcenters of concentration such as Bakhtaran in Iran. However, in Serbia and Montenegro, the province of Kosovo had a high frequency of CB resistant accessions (36%, n = 100) (Fig. 1B), and in one locality in the south of the province 15 of 19 accessions collected from three specific locations within approximately 16 km of one another were resistant.
Dwarf Bunt Resistance
Resistance to DB occurs in the same general area as CB resistance (Fig. 2A), but DB resistance is less common. Two centers of concentration for DB resistance are apparent, one in Serbia and Montenegro and the other in eastern Turkey and Iran (Fig. 2B). The highest frequency of DB resistance occurred among accessions from the province of Hakkari in southeastern Turkey where 58% of the 48 accessions tested were resistant. Resistant accessions from Hakkari represent 76% (28 of 37) of the resistant accessions identified from Turkey. DB resistance in accessions from eastern Turkey is known to bunt researchers (Bruehl, 1990), but neither the high frequency of resistance within accessions from Hakkari province nor the occurrence of DB resistance in accessions from Iran and Serbia and Montenegro has been described previously.
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Fig. 2. Specific geographic locations where DB resistant and susceptible wheat landrace accessions were collected: A) pattern of occurrence from Europe through Eastern Asia and B) number of resistant accessions and frequency of resistance per 100 km by 100 km grid cell in the four country region where the most resistant accessions were found.
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Of 132 landrace accessions from Hakkari present in the NSGC, 85 have either spring or facultative growth habit. Few of these accessions were tested for DB resistance, yet some were reported to be DB resistant by others (Bruehl, 1990). Currently, DB data are available for five accessions from Hakkari classified as spring habit and of these four were resistant. Thus, it is likely that more DB resistant accessions could be identified from Turkey within the materials classified as spring and facultative habit and these will be tested in the future.
Within Turkey, data from the WorldClim database showed the mean precipitation for the coldest quarter of the year was 237 mm for the locations where DB resistant accessions originated compared to 155 mm for locations where susceptible accessions originated. Similarly, DB resistance was related to elevation of origin of the accession. Across the three countries where DB resistance was found, elevation at origin was available for 3958 accessions. Within this sample the frequency of DB resistance is significantly lower (1.5 vs. 2.9%, P < 0.05) for accessions from less than 1250 m than for accessions from higher elevations. These differences in precipitation and elevation are likely correlated with long-lasting snow cover that is required for infection by the DB pathogen (Goates, 1996).
Relationship to Awn, Glume, and Kernel Pigmentation
In both sets of data examined the occurrence of lightly pigmented kernels was positively associated with the occurrence of CB resistance, whereas lightly pigmented awn and glumes were associated with CB susceptibility (Table 3). The positive association between lightly pigmented kernels and CB resistance in the NSGC data was not due to accessions with white/amber kernels being overrepresented and accessions with more darkly pigmented kernels being underrepresented in the four countries that had the high frequency of CB resistance. For example, within Turkey, Serbia and Montenegro, and Macedonia 1375 accessions were classified with respect to kernel color and among these there was a negative association between resistance and red kernels (P = 10–6) and a positive association between resistance and white/amber kernels (P = 10–6). There was a weak, but significant (P < 0.01), association of dark kernel color with DB resistance.
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Table 3. Associations and the frequencies of accessions with lightly pigmented awns, glumes, and kernels with the frequency of common bunt resistance in landrace accessions of Triticum aestivum subsp. aestivum from the USDA National Small Grains Collection (NSGC) in two data sets.
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Phenotypic Diversity within and among Accessions from Subcenters of Resistance
The subcenters where the frequency of resistant accessions was exceptionally high, such as Hakkari province in Turkey for DB and Bakhtaran province in Iran for CB, could be due to the consequence of highly disease-conducive environments resulting in farmer-selection for resistant landraces over time, or stochastically, because of recurrent mutations for resistance that remained in the landrace populations (Qualset, 1975). For these two locations we examined the phenotypic diversity among the resistant accessions using data from the NSGC for Hakkari and from the 1991 UC Davis trial for Bakhtaran.
Many of the resistant accessions from Hakkari were collected by C. Sperling, H. Gecit, and D. Eser in the mid 1980s and a few were collected by J. Harlan in 1948 and by J. Hoffmann, M. Kanbertay, R.J. Metzger, and H. Sencer in 1979. Little morphoagronomic data are available for the resistant accessions, but based on the seed and spike images available in GRIN it is clear that the materials are morphologically diverse. Furthermore, there appears to be diversity within the accessions as expected for landraces. The NSGC has attempted to maintain the diversity within landraces, but population size bottlenecks have rendered many of them as uniform as single-plant derivatives. Some marketplace grain collections, such as those collected from Hakkari province, show diversity within the NSGC accessions. For example, seven DB resistant genotypes were selected from within PI 560603 which are morphologically diverse with respect to spike type, glume and kernel color. These selections were recently given new PI designations (PI 636145–PI 636151), as were several other resistant accessions selected from Hakkari collections. The environmental conditions in the southeastern Turkey province of Hakkari are probably highly conducive to the DB disease, resulting in farmer-selection of disease resistant landraces over time.
The variability in quantitative traits among CB-resistant accessions from the Bakhtaran province, Iran, was lower than the variability among CB-susceptible accessions for six of the nine traits assessed (Table 4). Similarly, for the quantitative traits except spike and awn length, the resistant accessions from Bakhtaran were significantly less variable than the other common wheat accessions tested in the 1991 Davis planting. The differences in variance were small, but as expected if the resistant Bakhtaran accessions were derived from the same or closely related landraces. The high frequency of resistant accessions from this area may be the result of selection pressure for resistance induced in highly disease-conducive environments. Genes and phenotypes occurring at high frequencies would have been taken by collectors repeatedly by chance because the CB disease will not be apparent in most instances of field, farm stores, or market sources. Investigations with molecular markers (Driesigaker et al., 2004, 2005) may shed light on this unusual observation.
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Table 4. Mean ( ), variance (s2), coefficient of variation (cv), and ratio of variances (F-value) for quantitative traits in 106 accessions resistant to common bunt from Bakhtaran province, Iran compared to 142 susceptible accessions from the same province and to 1858 other accessions from Iran.
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In summary, we have identified geographic centers of concentration for both CB and DB in common wheat landrace accessions from the NSGC and have found that lightly pigmented kernels are associated with CB resistance. In addition, geographic subcenters of concentration were revealed in Kosovo province in Serbia and Montenegro and in Bakhtaran province in Iran for CB resistance, and in Hakkari province in Turkey for DB resistance. This information will be useful in guiding further exploration for sources of genes for bunt resistance and for the study of resistance gene diversity within the centers. Such information can also be used to target further collection efforts aimed at finding new resistance gene sources for these two diseases. Based on the analysis of variability of accessions from Bakhtaran province, where CB resistance was exceptionally frequent, genetic analyses would be useful to determine if these accessions were mono- or polymorphic for specific CB resistance genes.
Supplemental Table 1. Accesssions of Triticum aestivum var. aestivum from the National Small Grains Collection resistant to common bunt disease. Only data for the landrace accessions were included in the analysis presented in the paper.
Accession Prefix
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Accession number
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Name
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Status
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Origin
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| CItr |
4306 |
8 |
LANDRACE |
Iran |
| CItr |
7368 |
G 334 |
BREEDING |
United States |
| CItr |
11432 |
A-2–59–14 |
BREEDING |
United States |
| CItr |
11438 |
27461C-2–6-1 |
BREEDING |
United States |
| CItr |
11471 |
2421–7.19.32 |
BREEDING |
United States |
| CItr |
11473 |
McFadden 1280 |
BREEDING |
United States |
| CItr |
11491 |
White Russian |
CULTIVATED |
China |
| CItr |
11532 |
G2343-A-4–28 |
BREEDING |
United States |
| CItr |
11543 |
Utah Q231–17 |
BREEDING |
United States |
| CItr |
11576 |
TURKEY SELECTION |
BREEDING |
United States |
| CItr |
11617 |
|
BREEDING |
United States |
| CItr |
11635 |
RENOWN |
CULTIVAR |
Canada |
| CItr |
11650 |
RL 716 |
BREEDING |
Canada |
| CItr |
11713 |
Ns. 2594 |
BREEDING |
United States |
| CItr |
11721 |
RL 1114 |
BREEDING |
Canada |
| CItr |
11723 |
N 1264 |
BREEDING |
United States |
| CItr |
11775 |
Ns. 2590 |
BREEDING |
United States |
| CItr |
11779 |
Ns. 2687 |
BREEDING |
United States |
| CItr |
11786 |
N 1250 |
BREEDING |
United States |
| CItr |
11787 |
N 1249 |
BREEDING |
United States |
| CItr |
11789 |
II-28–16 |
BREEDING |
United States |
| CItr |
11790 |
II-28–68 |
BREEDING |
United States |
| CItr |
11869 |
REGENT |
CULTIVAR |
Canada |
| CItr |
11871 |
II-28–102 |
BREEDING |
United States |
| CItr |
11882 |
N 1349 |
BREEDING |
United States |
| CItr |
11884 |
N 1330 |
BREEDING |
United States |
| CItr |
11885 |
N 1098–28 |
BREEDING |
United States |
| CItr |
11891 |
II-29–53 |
BREEDING |
United States |
| CItr |
11892 |
II-28–27 |
BREEDING |
United States |
| CItr |
11898 |
II-29–60 |
BREEDING |
United States |
| CItr |
11931 |
N 1466 |
BREEDING |
United States |
| CItr |
11937 |
GREAT NORTHERN |
CULTIVAR |
Canada |
| CItr |
11940 |
PREMIER |
CULTIVAR |
United States |
| CItr |
11968 |
Nebr. Sel. 363452 |
BREEDING |
United States |
| CItr |
12005 |
Ns. No. 2747 |
BREEDING |
United States |
| CItr |
12006 |
Ns. 2800 |
BREEDING |
United States |
| CItr |
12012 |
RL 1333 |
BREEDING |
Canada |
| CItr |
12040 |
II-29–57 |
BREEDING |
United States |
| CItr |
12042 |
I-38–3 |
BREEDING |
United States |
| CItr |
12056 |
N 1637 |
BREEDING |
United States |
| CItr |
12058 |
SD 1463–26 |
BREEDING |
United States |
| CItr |
12187 |
KENYA 117C |
CULTIVAR |
Kenya |
| CItr |
12309 |
II-36–13 |
BREEDING |
United States |
| CItr |
12317 |
N 1753 |
BREEDING |
United States |
| CItr |
12318 |
NEWTHATCH |
CULTIVAR |
United States |
| CItr |
12324 |
N 1769 |
BREEDING |
United States |
| CItr |
12354 |
N 1609 |
BREEDING |
United States |
| CItr |
12358 |
Ns. 3111 |
BREEDING |
United States |
| CItr |
12360 |
Ns. 3096 |
BREEDING |
United States |
| CItr |
12367 |
N 1535 |
BREEDING |
United States |
| CItr |
12431 |
N. 1840 |
BREEDING |
United States |
| CItr |
12432 |
II-38–19 |
BREEDING |
United States |
| CItr |
12433 |
II-38–14 |
BREEDING |
United States |
| CItr |
12437 |
Ns. 3129 |
BREEDING |
United States |
| CItr |
12492 |
N 2035 |
BREEDING |
United States |
| CItr |
12493 |
N 2012 |
BREEDING |
United States |
| CItr |
12521 |
Huntley 4a |
BREEDING |
United States |
| CItr |
12542 |
N 1843–41 |
BREEDING |
United States |
| CItr |
12547 |
II-39–57 |
BREEDING |
United States |
| CItr |
12548 |
N 3264 |
BREEDING |
United States |
| CItr |
12549 |
N 2092 |
BREEDING |
United States |
| CItr |
12634 |
II-42–22 |
BREEDING |
United States |
| CItr |
12637 |
N 2232 |
BREEDING |
United States |
| CItr |
12642 |
Ns. 3269 |
BREEDING |
United States |
| CItr |
12643 |
Ns. 3274 |
BREEDING |
United States |
| CItr |
12644 |
Ns. 3282 |
BREEDING |
United States |
| CItr |
12645 |
Ns. 3284 |
BREEDING |
United States |
| CItr |
12680 |
BUNT RES ELGIN 1 |
BREEDING |
United States |
| CItr |
12724 |
Kansas No. 47B121 |
BREEDING |
United States |
| CItr |
12732 |
1416 A-1–8-3–2 |
BREEDING |
United States |
| CItr |
12735 |
1416 A-1–2-3–2 |
BREEDING |
United States |
| CItr |
12737 |
1465 A-1–5-4–1 |
BREEDING |
United States |
| CItr |
12738 |
1464 A-1–24–1-1 |
BREEDING |
United States |
| CItr |
12741 |
Ns. 3291 |
BREEDING |
United States |
| CItr |
12742 |
Ns. 3684 |
BREEDING |
United States |
| CItr |
12746 |
N. 1924.44 |
BREEDING |
United States |
| CItr |
12785 |
N. 2223 |
BREEDING |
United States |
| CItr |
12786 |
Ns. 3679 |
BREEDING |
United States |
| CItr |
12822 |
III-47–36 |
BREEDING |
United States |
| CItr |
12839 |
RL 2632 |
BREEDING |
Canada |
| CItr |
12849 |
RL 2667 |
BREEDING |
Canada |
| CItr |
12850 |
RL 2709 |
BREEDING |
Canada |
| CItr |
12851 |
Kansas No. 462666 |
BREEDING |
United States |
| CItr |
12852 |
Kansas No. 44767 |
BREEDING |
United States |
| CItr |
12853 |
Kansas No. 431413 |
BREEDING |
United States |
| CItr |
12867 |
Colo. F.C. 1197 |
BREEDING |
United States |
| CItr |
13043 |
Ns. 3880.227 |
BREEDING |
United States |
| CItr |
13092 |
II-40–107 |
BREEDING |
United States |
| CItr |
13100 |
SELKIRK |
CULTIVAR |
Canada |
| CItr |
13152 |
Ns. 3880.127 |
BREEDING |
United States |
| CItr |
13199 |
SD Sel. 56–45 |
BREEDING |
United States |
| CItr |
13266 |
AWNED ELGIN 2 |
BREEDING |
United States |
| CItr |
13332 |
PEMBINA |
CULTIVAR |
Canada |
| CItr |
13451 |
ND 152 |
BREEDING |
United States |
| CItr |
13691 |
Sel. 18–5 |
BREEDING |
United States |
| CItr |
13729 |
LUFT |
CULTIVAR |
United States |
| CItr |
13738 |
Sel. 6 |
BREEDING |
United States |
| CItr |
13824 |
II-58–14 |
BREEDING |
United States |
| CItr |
13837 |
Sel. C61–9 |
BREEDING |
United States |
| CItr |
13958 |
WALDRON |
CULTIVAR |
United States |
| CItr |
14107 |
SNOW MOLD TOLERANT SELECTION 2 |
BREEDING |
United States |
| CItr |
14127 |
NORDMAN |
CULTIVAR |
United States |
| CItr |
14128 |
PLAINSMAN |
CULTIVAR |
United States |
| CItr |
14267 |
DT 183 |
BREEDING |
Canada |
| CItr |
14275 |
Q 2331–34 |
BREEDING |
Canada |
| CItr |
14290 |
LA 1491 |
BREEDING |
Mexico |
| CItr |
15001 |
57–349 |
LANDRACE |
Nepal |
| CItr |
17576 |
6720–10 |
BREEDING |
United States |
| CItr |
17725 |
GREER |
CULTIVAR |
United States |
| CItr |
17730 |
ID 77–53–23-B |
BREEDING |
United States |
| CItr |
17731 |
ID 75–53–7 |
BREEDING |
United States |
| CItr |
17734 |
ID 75–55–19 |
BREEDING |
United States |
| CItr |
17755 |
RL 6043 |
BREEDING |
Canada |
| CItr |
17838 |
ID 72–5059 |
BREEDING |
United States |
| CItr |
17841 |
ID 74–53/18 |
BREEDING |
United States |
| CItr |
17842 |
ID 77–53/23-B |
BREEDING |
United States |
| PI |
8818 |
Koola |
LANDRACE |
Iraq |
| PI |
40946 |
Type No. 8A |
LANDRACE |
Pakistan |
| PI |
40956 |
Graecum |
LANDRACE |
Pakistan |
| PI |
41020 |
Kizil Bogara |
LANDRACE |
Uzbekistan |
| PI |
68096 |
BELOKOLOSKA |
CULTIVAR |
Russian Federation |
| PI |
68176 |
CItr 8523 |
CULTIVATED |
Russian Federation |
| PI |
71106 |
BELOKOLOSKA |
CULTIVAR |
Russian Federation |
| PI |
74084 |
BELOKOLOSKA |
CULTIVAR |
Russian Federation |
| PI |
74492 |
CItr 9319 |
BREEDING |
Russian Federation |
| PI |
78814 |
CItr 10112 |
LANDRACE |
Georgia |
| PI |
94359 |
52ASW |
LANDRACE |
Ukraine |
| PI |
94364 |
59BSW |
LANDRACE |
Armenia |
| PI |
94593 |
573 |
LANDRACE |
Russian Federation |
| PI |
106163 |
G 1–6-0 |
BREEDING |
Australia |
| PI |
106177 |
G 1–0 |
BREEDING |
Australia |
| PI |
106197 |
G 316–0-0 |
BREEDING |
Australia |
| PI |
106208 |
G 240–85–0 |
BREEDING |
Australia |
| PI |
106210 |
G 271–1-2 |
BREEDING |
Australia |
| PI |
106217 |
|
BREEDING |
Australia |
| PI |
117727 |
2716 |
BREEDING |
Australia |
| PI |
117762 |
2716 |
BREEDING |
Australia |
| PI |
124900 |
E-29-G-3-LO |
BREEDING |
Australia |
| PI |
131276 |
C 10535 |
BREEDING |
Australia |
| PI |
131376 |
|
BREEDING |
Australia |
| PI |
131384 |
C 10534 |
BREEDING |
Australia |
| PI |
131391 |
0–7-4–0 |
BREEDING |
Australia |
| PI |
131393 |
0–19–4-0 |
BREEDING |
Australia |
| PI |
133291 |
EUREKA 2 |
CULTIVAR |
Australia |
| PI |
133292 |
EUREKA |
CULTIVAR |
Australia |
| PI |
133293 |
3781 |
BREEDING |
Australia |
| PI |
133299 |
9010 |
BREEDING |
Australia |
| PI |
142222 |
QUADRAT |
CULTIVAR |
Australia |
| PI |
142379 |
364–5G-40 |
BREEDING |
Australia |
| PI |
142380 |
366–7-G-40 |
BREEDING |
Australia |
| PI |
142381 |
388–9-G-40 |
BREEDING |
Australia |
| PI |
142382 |
393–4-G-40 |
BREEDING |
Australia |
| PI |
142397 |
755-G-40 |
BREEDING |
Australia |
| PI |
164362 |
Kanak |
LANDRACE |
India |
| PI |
165141 |
Sivas |
LANDRACE |
Turkey |
| PI |
165163 |
Yumusak |
LANDRACE |
Turkey |
| PI |
165175 |
Ak |
LANDRACE |
Turkey |
| PI |
166219 |
Ak |
LANDRACE |
Turkey |
| PI |
166252 |
Yumusak |
LANDRACE |
Turkey |
| PI |
166258 |
Haci Yusuf |
LANDRACE |
Turkey |
| PI |
166260 |
Germir |
LANDRACE |
Turkey |
| PI |
166261 |
Zerun |
LANDRACE |
Turkey |
| PI |
166267 |
Zerin |
LANDRACE |
Turkey |
| PI |
166278 |
Guzluk Yillik |
LANDRACE |
Turkey |
| PI |
166282 |
Zeran |
LANDRACE |
Turkey |
| PI |
166283 |
Yillik |
LANDRACE |
Turkey |
| PI |
166293 |
Erik Kislik |
LANDRACE |
Turkey |
| PI |
166296 |
Saritopbas |
LANDRACE |
Turkey |
| PI |
166299 |
Ak |
LANDRACE |
Turkey |
| PI |
166310 |
Yumusak |
LANDRACE |
Turkey |
| PI |
166477 |
Cakirli |
LANDRACE |
Turkey |
| PI |
166481 |
Sumdar |
LANDRACE |
Turkey |
| PI |
166494 |
Ak |
LANDRACE |
Turkey |
| PI |
166562 |
Yumusak |
LANDRACE |
Turkey |
| PI |
166622 |
Sari Bursa |
LANDRACE |
Turkey |
| PI |
166703 |
Kurt |
LANDRACE |
Turkey |
| PI |
166748 |
Yazlik |
LANDRACE |
Turkey |
| PI |
166927 |
Sam |
LANDRACE |
Turkey |
| PI |
167508 |
2141 |
LANDRACE |
Turkey |
| PI |
167551 |
2721 |
LANDRACE |
Turkey |
| PI |
167694 |
3888 |
LANDRACE |
Turkey |
| PI |
167712 |
3944 |
LANDRACE |
Turkey |
| PI |
167731 |
3988 |
LANDRACE |
Turkey |
| PI |
167772 |
4091 |
LANDRACE |
Turkey |
| PI |
167773 |
4093 |
LANDRACE |
Turkey |
| PI |
167780 |
4104 |
LANDRACE |
Turkey |
| PI |
167814 |
4197 |
LANDRACE |
Turkey |
| PI |
167817 |
4204 |
LANDRACE |
Turkey |
| PI |
167818 |
4208 |
LANDRACE |
Turkey |
| PI |
167824 |
4219 |
LANDRACE |
Turkey |
| PI |
167857 |
4298 |
LANDRACE |
Turkey |
| PI |
167868 |
4318 |
LANDRACE |
Turkey |
| PI |
168486 |
9368a |
LANDRACE |
India |
| PI |
170996 |
6615 |
LANDRACE |
Turkey |
| PI |
171006 |
3918 |
LANDRACE |
Turkey |
| PI |
171007 |
3920 |
LANDRACE |
Turkey |
| PI |
171018 |
3935 |
LANDRACE |
Turkey |
| PI |
171023 |
4066 |
LANDRACE |
Turkey |
| PI |
171029 |
4076 |
LANDRACE |
Turkey |
| PI |
171033 |
4109 |
LANDRACE |
Turkey |
| PI |
171052 |
4263 |
LANDRACE |
Turkey |
| PI |
172201 |
186 |
BREEDING |
Australia |
| PI |
172533 |
7698 |
LANDRACE |
Turkey |
| PI |
172534 |
Kirik |
LANDRACE |
Turkey |
| PI |
172554 |
8355 |
LANDRACE |
Turkey |
| PI |
172561 |
Sertak |
LANDRACE |
Turkey |
| PI |
172565 |
Menceki |
LANDRACE |
Turkey |
| PI |
173384 |
6517 |
LANDRACE |
Turkey |
| PI |
173388 |
6535 |
LANDRACE |
Turkey |
| PI |
173395 |
6627 |
LANDRACE |
Turkey |
| PI |
173399 |
Sumeder Cakerlisi |
LANDRACE |
Turkey |
| PI |
173444 |
Kirik |
LANDRACE |
Turkey |
| PI |
173450 |
Kirik |
LANDRACE |
Turkey |
| PI |
173471 |
Kose |
LANDRACE |
Turkey |
| PI |
173474 |
Kose |
LANDRACE |
Turkey |
| PI |
173477 |
8032 |
LANDRACE |
Turkey |
| PI |
173478 |
8038 |
LANDRACE |
Turkey |
| PI |
177977 |
184/2 |
BREEDING |
Turkey |
| PI |
178000 |
165/5 |
BREEDING |
Turkey |
| PI |
178007 |
193/2 |
BREEDING |
Turkey |
| PI |
178101 |
Rus |
LANDRACE |
Turkey |
| PI |
178172 |
141/3 |
BREEDING |
Turkey |
| PI |
178175 |
144/10 |
BREEDING |
Turkey |
| PI |
178182 |
7607 |
LANDRACE |
Turkey |
| PI |
178193 |
8818 |
LANDRACE |
Turkey |
| PI |
178194 |
8820 |
LANDRACE |
Turkey |
| PI |
178206 |
Saribas |
LANDRACE |
Turkey |
| PI |
178210 |
YAYLA 305 |
CULTIVAR |
Turkey |
| PI |
178224 |
10227 |
LANDRACE |
Turkey |
| PI |
178687 |
Dimcuit |
LANDRACE |
Turkey |
| PI |
178689 |
184/5 |
BREEDING |
Turkey |
| PI |
178692 |
182/3 |
BREEDING |
Turkey |
| PI |
178694 |
146/6 |
BREEDING |
Turkey |
| PI |
178695 |
145/2 |
BREEDING |
Turkey |
| PI |
178697 |
140/3 |
BREEDING |
Turkey |
| PI |
178705 |
175/2 |
BREEDING |
Turkey |
| PI |
178713 |
142/5 |
BREEDING |
Turkey |
| PI |
178723 |
142/6 |
BREEDING |
Turkey |
| PI |
178726 |
193/5 |
BREEDING |
Turkey |
| PI |
178737 |
165/6 |
BREEDING |
Turkey |
| PI |
178748 |
6499 |
BREEDING |
Turkey |
| PI |
178750 |
9735 |
LANDRACE |
Syria |
| PI |
178767 |
62/2 |
LANDRACE |
Turkey |
| PI |
178776 |
YAYLA 305 |
CULTIVAR |
Turkey |
| PI |
178777 |
73/1 |
LANDRACE |
Turkey |
| PI |
178784 |
Ruto |
LANDRACE |
Turkey |
| PI |
178793 |
Beleke |
LANDRACE |
Turkey |
| PI |
178801 |
10325 |
LANDRACE |
Turkey |
| PI |
178804 |
10341 |
LANDRACE |
Turkey |
| PI |
180636 |
Strain No. 3524/38 |
BREEDING |
Germany |
| PI |
180638 |
Strain No. 1179/42 |
BREEDING |
Germany |
| PI |
181256 |
14 |
LANDRACE |
Afghanistan |
| PI |
185275 |
H912 SEL 47 933 |
BREEDING |
Argentina |
| PI |
185298 |
H 1092 47–683 |
BREEDING |
Argentina |
| PI |
185867 |
II-116–2C-5C-(1–3C)-16C |
BREEDING |
Mexico |
| PI |
189780 |
BLE DUR D 115 |
BREEDING |
Tunisia |
| PI |
189786 |
Sel. 49–4796 H544 |
BREEDING |
Argentina |
| PI |
189804 |
Sel. 49–4809 H653 |
BREEDING |
Argentina |
| PI |
189821 |
Sel. 49–4831 H1035 |
BREEDING |
Argentina |
| PI |
189840 |
Sel. 49–2854 H1168 |
BREEDING |
Argentina |
| PI |
190154 |
HOHENHEIMER BASTARD |
CULTIVAR |
Germany |
| PI |
190490 |
ELLA |
CULTIVAR |
Sweden |
| PI |
191122 |
Jeja de Barcelona |
LANDRACE |
Spain |
| PI |
191135 |
Marceno de Lerida |
LANDRACE |
Spain |
| PI |
191363 |
Russie 062 |
CULTIVATED |
Italy |
| PI |
191391 |
Tricoccum |
CULTIVATED |
Ethiopia |
| PI |
191496 |
H 2 B 13326 |
CULTIVATED |
Portugal |
| PI |
191559 |
H 15 N 13356 |
CULTIVATED |
Portugal |
| PI |
191584 |
HNAD 12228 |
CULTIVATED |
Portugal |
| PI |
191706 |
Bladette de Besplas |
LANDRACE |
France |
| PI |
191872 |
Arrancada |
CULTIVATED |
Portugal |
| PI |
192249 |
Bohom Vaxelv Seleta |
CULTIVATED |
Czech Republic |
| PI |
192393 |
SELECTY PRESIVKA |
CULTIVAR |
Czechoslovakia |
| PI |
192433 |
Egipcio |
CULTIVATED |
Portugal |
| PI |
192569 |
Forma Vinda de Varmland |
LANDRACE |
Sweden |
| PI |
192576 |
BON FERMIER |
CULTIVAR |
France |
| PI |
202786 |
|
BREEDING |
Peru |
| PI |
204035 |
Santa Marta |
LANDRACE |
Portugal |
| PI |
211645 |
220–39 |
CULTIVATED |
Turkey |
| PI |
211667 |
1467 |
CULTIVATED |
Turkey |
| PI |
212820 |
1 |
CULTIVATED |
Uruguay |
| PI |
213570 |
AQUILA |
CULTIVAR |
Italy |
| PI |
213572 |
Gzal. Mitre |
CULTIVATED |
Argentina |
| PI |
213582 |
D.I.V. 6703 |
BREEDING |
Argentina |
| PI |
213591 |
D.I.V. 6712 |
BREEDING |
Argentina |
| PI |
213594 |
D.I.V. 6715 |
BREEDING |
Argentina |
| PI |
213602 |
D.I.V. 6723 |
BREEDING |
Argentina |
| PI |
213682 |
BUCK 62/52 |
BREEDING |
Argentina |
| PI |
220433 |
Line 1167–68 |
BREEDING |
|
TOP
ABSTRACT
INTRODUCTION
