April 2017 Additions
Bishaw, Z.; Alemu, D.
The paper presents smallholder farmers' perceptions on attributes of bread wheat varieties based on primary data collected from 524 households in four major wheat growing areas of Ethiopia. The results indicated high value of attainment indices for improved varieties compared to landraces, which shows how the demanded attributes are embodied more in improved ones. Grain yield and yellow and stem rust resistance are attributes that are desired most compared to others. However, there is high variability in attainment indices among improved varieties for the different attributes, which suggests the need to target varieties for the different environments including disease and drought tolerance. The results also showed inconsistency between the value of attainment indices of varieties and the amount of seed supplied by the formal sector, which resulted in mismatch between demand and supply leading to considerable carryover seed. The formal sector needs to consider diversifying its bread wheat varietal portfolio and increase its capacity for seed supply to respond to emerging challenges and effectively address farmers' preferences.
Kassa, M. T.; You, F. M.; Hiebert, C. W.; Pozniak, C. J.; Fobert, P. R.; Sharpe, A. G.; Menzies, J. G.; Humphreys, D. G.; Harrison, N. R.; Fellers, J. P.; McCallum, B. D.; McCartney, C. A.
Lr16 is a widely deployed leaf rust resistance gene in wheat (Triticum aestivum L.) that is highly effective against the North American Puccinia triticina population when pyramided with the gene Lr34. Lr16 is a seedling leaf rust resistance gene conditioning an incompatible interaction with a distinct necrotic ring surrounding the uredinium. Lr16 was previously mapped to the telomeric region of the short arm of wheat chromosome 2B. The goals of this study were to develop numerous single nucleotide polymorphism (SNP) markers for the Lr16 region and identify diagnostic gene-specific SNP marker assays for marker-assisted selection (MAS).
Genetic analysis and molecular mapping of resistance to Puccinia striiformis f. sp. pseudo-hordei in common wheat
Dracatos, P.M., Haghdoust, R., Singh, D., and Park, R.F.
This is the first genetic study reporting on the interaction and molecular mapping of resistance to the barley grass stripe rust pathogen (Puccinia striiformis f. sp. pseudo-hordei, Psph) in common wheat. Seedlings of 638 wheat accessions were tested and it was determined that wheat is a near-nonhost to Psph based on rare susceptibility observed in <2% of commercial cultivars and <5% of wheat landraces. As previously observed for P. striiformis f. sp. tritici (Pst), the Australian cultivar Teal was highly susceptible to Psph. In contrast, a selection of cv. Avocet carrying complementary resistance genes Yr73 and Yr74 (Avocet R; AvR) was resistant. The Teal × AvR (T/A) doubled haploid (DH) population was used to map resistance in AvR to Psph. Infection types on the T/A DH lines inoculated with Psph and Pst indicated that all DH lines carrying both Yr73 and Yr74 were also resistant to Psph; however, fewer DH lines were susceptible to Psph than expected, suggesting the resistance was more complex. QTL analysis using 9053 DArT-Seq markers determined that resistance to Psph was polygenically inherited and mapped to chromosomes 3A, 3D, 4A and 5B. The 3DL and 5BL markers co-located with Yr73 and Yr74, suggesting an overlap between host and non-host resistance mechanisms.