Genetic Analysis of the Latent Period of Stripe Rust in Wheat Seedlings

Abstract

Genetics of slow-rusting resistance to yellow rust (Puccinia striiformis f.sp. tritici) was studied by a half-diallel design using six wheat varieties, Tiritea (susceptible), Tancred, Kotare, Otane, Karamu, and Briscard. The parents and 15 F 1 progenies were evaluated in the greenhouse by three pathotypes 7E18A ) , 38E0A + , and 134E134A + . The latent period was measured as the number of days from inoculation to the appearance of the first pustule. For each pathotype a randomized complete block design was used and data were analysed by methods of Griffing and Hayman. The range of average degree of dominance was from complete dominance to over-dominance. Positive and negative degrees of dominance were observed for each pathotype that showed the reversal of dominance. Analysis of variance showed the importance of both additive and dominance effects in controlling the latent period. Broad-sense heritabilities were 0.99 and narrow-sense heritabilities ranged from 0.85 to 0.94. Briscard and Karamu for the pathotypes 38E0A + and 134E134A + , Kotare for the pathotype 7E18A ) and Tancred for the pathotype 38E0A + had significant and positive general combining ability (GCA) (more resistance) for latent period. The crosses of Kotare with Tancred, Briscard and Karamu indicated the highest and positive specific combining ability (SCA) for the pathotype 7E18A ) . Significant additive genetic component and moderate narrow-sense heritability indicate the possibility of improving for longer latent period of stripe rust in breeding programmes.U. S.

Effect of yellow rust on yield components of barley cultivars with race-specific and slow rusting resistance to yellow rust

“…Consequently, cultivars with low level CI and other slow rusting parameters most probably will have durable resistance genes, such as HTAP and slow rusting, and their resistance can be lasted for a long time. Because this kind of resistance is controlled by more than one gene, in other words is oligogenic or polygenic (Dehghani and Moghaddam 2004).…”

Application of Phenotypic and Molecular Markers to Combine Genes for Durable Resistance against Rust Virulences and High Yield Potential in Wheat

“…Cultivars possessing slow rusting illustrated lower AUDPC at adult plant stage have race-nonspecific resistance as also described by (Sandoval-Islas et al, 1998 andSingh et al, 2005). Because the durable resistance, like slow rusting and hightemperature adult plant resistance is polygenic (at least 2-3 controlling genes) as described elsewhere (Dehghani and Moghaddam, 2004), therefore, it remains successful for longer time, even if the pathogen under goes mutation. Hence, as per our findings, lines showing low frequency of disease severity with lower AUDPC values could be considered as slow rusting lines carrying durable rust resistance against Lr34, Lr46 and Sr2 virulences, which can be utilized in breeding programs.…”

Exploring Durable Genetic Resistance against Leaf Rust through Phenotypic Characterization and Lr34Linked STS Marker in Wheat Germplasm

“…Cultivars possessing slow rusting illustrated lower rAUDPC at adult stage have race-nonspecific resistance as also described by Sandoval-Islas et al (1998) and Singh et al (2005). Because the durable resistance, like slow rusting and High-Temperature Adult Plant resistance is polygenic (at least 2-3 controlling genes) as also described by Dehghani and Moghaddam (2004), therefore it remains successful for longer time, even if the pathogen under goes mutations. Hence, by our findings, lines showing low frequency of disease severity with lower AUDPC values could be considered as slow rusting lines carrying durable rust resistance against Puccinia triticina Eriks and could be utilized in breeding programs.…”