Wild species are sources and donors of many valuable traits for wheat improvement. We studied winter wheat introgression lines for productivity traits, disease resistance, and protein, globulin, gliadin and glutenin contents as well as grain mineral concentrations. Laboratory and field studies allowed selection in populations segregating for resistance to yellow rust and leaf rust. Lines 1718, 1721-9, 1721-4, 1675 and 1727 had the highest yields (6.2 t/ha) and stable leaf rust and stem rust resistances, but were still variable in response to stripe rust (30-80 S). Lines 1718 (Bezostaya 1 x Ae. cylindrica, genomes CCDD) and 1721 (Bezostaya 1 x T. militinae2 - 6, ABG) were resistant to stripe rust in trials at yield levels of 3.7-7.6 t/ha and from 5.7 to 8.2 t/ha, respectively. Line 1675 (Zhetisu x T. kiharae, ABGD) was resistant to all three rusts. Line 1676 (Steklovidnaya 24 x T. timopheevi, ABG) was resistant to LR and SR at a yield level of 8.3 t/ha, and 1671 (Zhetisu x T. militinae, ABG) was resistant to YR and SR at a yield level of 7.5 t/ha. Protein contents of the lines ranged from 13.6 to 18.4%, and grain mineral contents were above average.
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Landraces and wild relatives of wheat are rich repositories of new rust resistance genes. Landraces are preferred over wild relatives for the absence of deleterious effects associated with large alien segments. A common wheat landrace, AUS 27969 (ex Portugal), from the Watkins Collection was resistant under field conditions and produced seedling infection type (IT) 2C against the widely virulent Australian Puccinia striiformis f. sp. tritici (Pst) pathotype 134 E16 A+ Yr17+ Yr27+. AUS 27969 was crossed with the susceptible genotype Avocet S (AvS) and the distribution of F3 lines conformed to monogenic segregation [40 non-segregating resistant (NSR), 93 segregating (Seg), and 37 non-segregating susceptible (NSS); ?2 = 1.61, P2d.f. >0.05] when tested with the same pathotype at the seedling stage. The population is currently being selfed to F6. DNA from NSR and NSS lines will be sent for high throughput analysis to identify the genomic region carrying the resistance gene. Resistance-linked SNPs will be mapped on the F6 RIL population. The resistance gene will be backcrossed into modern Australian wheat backgrounds.
The International Winter Wheat Improvement Program (Turkey-CIMMYT-ICARDA) conducted a national inventory of wheat landraces in Turkey from 2009-2014. The material in this study were landraces from 10 provinces (Afyon, Aksaray, Burdur, Eskişehir, Karaman, Konya, Kütahya, Nevşehir, Niğde and Uşak) collected in 2009-2010, head-rowed and increased for evaluation in a yield trial in 2012-2013 in Konya province (200 entries, 2 replicates). Drought tolerant cultivars Karahan-99 and Gerek-79 served as checks, each repeated 8 times. The average yıeld of selections from the landraces was 2.95 t/ha compared to 3.7 t/ha for Karahan-99 and 2.8 t/ha for Gerek-79. The mean yıeld of the ten best landrace selections was 3.9 t/ha. In separate disease tests 5% and 11% of selections from the landraces were resistant and moderately resistant to stripe rust, respectively. Four landraces selections (Sahman-Aksaray, Kırmızı Buğday-Uşak, Kobak-Kütahya, Koca Buğday-Burdur) had higher grain yield than Karahan-99 and Gerek-79 and were resistant to stripe rust. There is some likelihood that this resistance is of a durable nature. The selected lines can be used in breeding programs targeting improved dryland performance while improving durability of stripe rust resistance in modern cultivars.
The wild relatives of wheat represent a vast resource of potentially useful genes for agriculture. The genus Aegilops has provided several rust resistance genes used in commercial cultivars. Here we report progress on mapping of potentially new stem and leaf rust resistance from Ae. caudata, Ae. searsii and Ae. mutica (Amblyopyrum muticum). Addition lines derived from the amphiploids Alcedo/ Ae. caudata, TA3368, CS/ Ae. mutica, TA8024 (both from Wheat Genetics Resource Center, Kansas State University, USA) and CS/ Ae. searsii TE10 (kindly provided by Dr Moshe Feldman, Weizmann Institute, Rehovot, Israel) were produced after backcrossing the amphiploids with Australian cv. Angas or Westonia. Backcrossed generations were screened for stem rust and leaf rust responses and both resistant and susceptible plants were sampled for DNA marker analysis. Stem rust resistant plants derived from the Ae. caudata amphiploid and leaf rust resistant plants derived from the Ae. searsii amphiploid showed the presence of non-wheat marker bands after hybridizing restricted genomic DNA with the Triticeae group 5 RFLP probe PSR128, and after PCR using EST-based primers specific for Triticeae group 5. Susceptible plants did not show those non-wheat molecular markers. Hence, stem rust resistance from Ae. caudata was allocated to chromosome 5C, and the resistance gene is temporarily named SrAec1t. Leaf rust resistance from Ae. searsii was allocated in a similar manner to chromosome 5Ss, and is temporarily named LrAesr1t. Leaf rust resistance transferred from Ae. mutica was traced to a 6T chromosome after associating resistance with the presence of Triticeae group 6 RFLP probes (including BCD001, BCD269, BCD276, BCD1426, CDO772, CDO1380, WG933) and that gene is temporarily named LrAmm1t. The addition lines involving the 5C, 5Ss and 6T chromosomes were crossed with Sears’ ph1b mutant to induce homoeologous recombination with related wheat chromosomes.