Effects of inoculum density and temperature on three components of leaf rust resistance controlled by Lr34 in wheat

Pretorius, Z. A.; Kloppers, F. J.; Drijepondt, S. C.

doi:10.1007/bf00033772

Cited by 22 publications

(11 citation statements)

References 21 publications

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“…latent period and smaller uredinia, but not reflected by infection types, in the line T34-13-5/1 inoculated with UVPrt13. The reliability of the individual components as measures of resistance was discussed in several studies (Broers & Wallenburg, 1989;Drijepondt & Pretorius, 1989;Jacobs & Kiriswa 1993;Pretorius et al, 1994). In the present study, a longer latent period appeared related to smaller and fewer uredinia of UVPrt13 on T34-13-5/1.…”

Section: Infection Types and Disease Severitysupporting

confidence: 62%

“…No pathotypes of P. recondita with virulence for adult plants of lines possessing Lr37 have been reported from southern Africa (Pretorius et al, 1990;Kloppers & Pretorius, 1994). However, pathotype UVPrt2 possessed slightly greater virulence (;1 cn ) than UVPrt13 (; cn ) on T37.…”

Section: Discussionmentioning

confidence: 98%

“…In a study on the effect of postinfection temperature on wheat with partial resistance to leaf rust, Broers & Wallenburg (1989) also found that infection frequency was the most variable component between different experiments and was not affected by temperature. Drijepondt & Pretorius (1989) and Pretorius et al (1994) also reported that uredinium density on lines with Lr34 was not influenced to the same degree by temperature as were other components of resistance. Jacobs & Kiriswa (1993) ascribed the inconsistency associated with this component to both experimental variation and environmental effects.…”

Section: Infection Types and Disease Severitymentioning

confidence: 95%

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Effects of combinations amongst genes Lr13, Lr34 and Lr37 on components of resistance in wheat to leaf rust

Kloppers

Pretorius

1997

Plant Pathology

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Gene pyramiding is a breeding strategy whereby host resistance genes are combined together with the objective of prolonging their usefulness in crops such as wheat (Triticum aestivum) for resistance to leaf rust caused by Puccinia recondita f.sp. tritici. When genes are combined they often give reactions different from those given by each component gene alone. Effects of gene combinations in lines Lr13 + Lr34 (T34-13), Lr13 + Lr37 (T13-37) and Lr34 + Lr37 (T34-37) were compared with those of the single gene lines CT263 (Lr13)(T13), RL6058 (Lr34)(T34), RL6081 (Lr37)(T37) and the leaf rust susceptible control, Thatcher. Infection types on plants infected with pathotypes UVPrt2 or UVPrt13 in the glasshouse, and disease severity in the field, demonstrated higher levels of resistance in the combination lines T13-37 and T34-37 than in the lines with the individual genes. The absence of sporulating uredinia in these combination lines prevented quantitative measurements of components such as latent period. In the T34-13 line, no increased resistance to pathotype UVPrt13 was apparent from assessment of the infection types in the glasshouse. Precise measurements of its resistance components showed, however, that it had a longer latent period and smaller uredinia and its resistance was highly effective in the field. There was variation in leaf rust severity amongst sister lines containing both Lr13 and Lr34, suggesting that increased resistance in T13-34 may not be controlled solely by these two genes themselves. Development of fungal structures, and the incidence and area displaying a hypersensitive reaction, were assessed using UV-1A and B-2A fluorescence microscopy filter combinations. Significant restriction of fungal growth during early postinfection stages occurred in the gene combination lines T34-13, T13-37 and T34-37. Colony size in these lines was also significantly reduced compared with that in the single gene lines T13, T34, T37 and the leaf rust-susceptible Thatcher, when either or both pathotypes possessed avirulence for one of the Lr genes. In the compatible T13-34/ UVPrt13 interaction no clear histological evidence of resistance enhancement was observed. The hypersensitive reaction in Lr37 alone or in combination and with either pathotypes, and Lr13 alone or in combination and with UVPrt2 indicated that the major component of the resistance mechanism is posthaustorial. Lr34 had the lowest hypersensitive index and even less hypersensitivity was observed in the Lr34/Lr37 combination line than in Lr37 alone. There was more prehaustorial abortion of infection structures in the line T34-37 than in T34 and T37 with isolate UVPrt2 but not with UVPrt13. It did not appear that abortion of infection structures was a major component of the resistance studied.

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Section: Infection Types and Disease Severitysupporting

confidence: 62%

Section: Discussionmentioning

confidence: 98%

Section: Infection Types and Disease Severitymentioning

confidence: 95%

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Effects of combinations amongst genes Lr13, Lr34 and Lr37 on components of resistance in wheat to leaf rust

Kloppers

Pretorius

1997

Plant Pathology

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“…studied slow rusting components in bread wheat and found that temperature and growth stage had little effect on uredinium size. Pretorius et al (1994) did not find an effect of inoculum concentration on uredinium size. In addition, Das et al (1993) showed that the narrow sense heritability of uredinium size was higher than that for latent period and receptivity, meaning that breeding for slow rusting resistance in bread wheat would be more efficient if selection is based on this component rather than on the other two.…”

Section: Discussionmentioning

confidence: 69%

Evaluation of slow rusting resistance components to leaf rust in CIMMYT durum wheats

et al. 2007

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Information about slow rusting resistance to leaf rust (Puccinia triticina) in durum wheat (Triticum turgidum var. durum) is limited. Three slow rusting components, latent period, receptivity, and uredinium size, were determined at the adult plant stage for seven durums with slow rusting resistance to leaf rust and two susceptible durums in three greenhouse experiments. Additionally, area under the disease progress curve (AUDPC) and final disease severity (FDS) were determined in three field trials under artificial epidemics with the same P. triticina race BBG/BN. Compared to the most susceptible check, the AUDPC and FDS of slow rusting resistant durums were significantly lower and ranged from 13-47 to 22-59%, respectively. The latent period was significantly longer (8.5-10.3 days) and uredinium size significantly smaller (8.1-14.8 · 10 -2 mm 2 ) on slow rusting durums than on the susceptible checks (8.0 days and 17.3-23.8 · 10 -2 mm 2 , respectively). Uredinium size was the most stable slow rusting component across experiments.Correlations between uredinium size versus AUDPC and uredinium size versus FDS for each environment were high (r = 0.86-0.88). Correlations between latent period and field parameters were significant (r = -0.60 to -0.80). Correlations between receptivity and the field parameters were not significant. A multiple regression analysis showed that the variation in AUDPC and FDS was significantly explained only by uredinium size (P < 0.0001). The best slow rusting resistant lines can be used for developing high-yielding durums with more durable resistance to leaf rust.

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“…The Lr34/Yr18 gene for resistance to leaf and stripe rust has been shown to be very important in durable rust resistance in wheat (Lagudah et al, 2009). Some of the early work on the Lr34 phenotype, which showed that the gene is detectable in seedlings at low temperatures and that several resistance components interact in adult plants, was done in South Africa (Drijepondt & Pretorius, 1989;1991;Pretorius et al, 1994). In addition, Kloppers and Pretorius (1997) quantified the effect of gene combinations involving Lr13, Lr34 and Lr37 in reducing leaf rust infection in adult plants.…”

Section: Wheat Rustsmentioning

confidence: 99%

An overview of the context and scope of wheat (Triticum aestivum) research in South Africa from 1983 to 2008

Smit¹,

Tolmay²,

Barnard³

et al. 2010

South African Journal of Plant and Soil

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The domestic requirement for wheat in South Africa is approximately 2.8 million tons and annually the shortfall on local production is imported to meet the demand. During the past 25 years two distinct wheat marketing mechanisms characterised the wheat industry, impacting significantly on both research and industry. In 1996 the single channel marketing system through the Wheat Board made way for a liberal marketing environment in which market forces of supply and demand determine price. This refocused most research activities on factors to lower input costs and risks, while increasing the profitability of wheat production. Significant challenges were experienced with much stricter milling and baking quality requirements impacting on not only the development of adapted wheat cultivars for South African conditions, but also on fertiliser and cultivar recommendations, as well as production practices. Minimum tillage, preharvest sprouting, as well as the threat of Russian wheat aphid and stripe rust were some of the pertinent challenges faced during this time. Significant scientific breakthroughs of international importance were made with regard to the physiological and biochemical nature of insect resistance and plant defence as well as the transfer of resistance genes from alien species. This review provides an overview of the most pertinent wheat research undertaken from 1983 to 2008.

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Effects of inoculum density and temperature on three components of leaf rust resistance controlled by Lr34 in wheat

Cited by 22 publications

References 21 publications

Effects of combinations amongst genes Lr13, Lr34 and Lr37 on components of resistance in wheat to leaf rust

Effects of combinations amongst genes Lr13, Lr34 and Lr37 on components of resistance in wheat to leaf rust

Evaluation of slow rusting resistance components to leaf rust in CIMMYT durum wheats

An overview of the context and scope of wheat (Triticum aestivum) research in South Africa from 1983 to 2008

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