Improved sources of resistance to ascochyta blight in chickpea

2009 ◽  
Vol 89 (1) ◽  
pp. 107-118 ◽  
Author(s):  
Rajamohan Chandirasekaran ◽  
Thomas D Warkentin ◽  
Yantai Gan ◽  
Steven Shirtliffe ◽  
Bruce D Gossen ◽  
...  

Successful chickpea production in western Canada typically requires multiple applications of fungicides to minimize the severity of ascochyta blight (AB) caused by Ascochyta rabiei (Pass.) Lab. Although planting resistant cultivars could be economical and environmentally safer than fungicide use, varieties with a high level of resistance are not available. The objective of this research was to identify potentially useful parents for breeding programs aimed at the northern Great Plains by assessing the AB reaction of 12 desi and 12 kabuli chickpea varieties for their AB reaction on leaves, stems and pods under two fungicide regimes. The experiment was conducted at Swift Current and Shaunavon, Saskatchewan, in 2004 and 2005. Differences in AB severity on leaves, stems and pods, seed yield and 1000-seed weight occurred among varieties at all site-years tested. The variation was greater among kabuli varieties than desi varieties. Ascochyta blight severity was generally lower under the high fungicide regime. A positive correlation in AB severity on leaves, stems and pods was observed, suggesting a lack of organ-specific reaction. Several promising varieties that combined improved levels of AB resistance, high yield, and large seed size were identified. Key words: Didymella rabiei, Ascochyta rabiei, Cicer arietinum, fungicide efficacy

Plant Disease ◽  
2009 ◽  
Vol 93 (5) ◽  
pp. 528-536 ◽  
Author(s):  
K. A. Wise ◽  
C. A. Bradley ◽  
J. S. Pasche ◽  
N. C. Gudmestad

Ascochyta blight, caused by Ascochyta rabiei (teleomorph: Didymella rabiei), is an important fungal disease of chickpea (Cicer arietinum). A monitoring program was established in 2005 to determine the sensitivity of A. rabiei isolates to the QoI (strobilurin) fungicides azoxystrobin and pyraclostrobin. A total of 403 isolates of A. rabiei from the Northern Great Plains and the Pacific Northwest were tested. Ninety-eight isolates collected between 2005 and 2007 were tested using an in vitro spore germination assay to determine the effective fungicide concentration at which 50% of conidial germination was inhibited (EC50) for each isolate–fungicide combination. A discriminatory dose of 1 μg/ml azoxystrobin was established and used to test 305 isolates from 2006 and 2007 for in vitro QoI fungicide sensitivity. Sixty-five percent of isolates collected from North Dakota in 2005, 2006, and 2007 and from Montana in 2007 were found to exhibit a mean 100-fold decrease in sensitivity to both azoxystrobin and pyraclostrobin when compared to sensitive isolates, and were considered to be resistant to azoxystrobin and pyraclostrobin. Under greenhouse conditions, QoI-resistant isolates of A. rabiei caused significantly higher amounts of disease than sensitive isolates on azoxystrobin- or pyraclostrobin-amended plants. These results suggest that disease control may be inadequate at locations where resistant isolates are present.


Author(s):  
Toby E. Newman ◽  
Silke Jacques ◽  
Christy Grime ◽  
Fiona L. Kamphuis ◽  
Robert C. Lee ◽  
...  

Chickpea production is constrained worldwide by the necrotrophic fungal pathogen Ascochyta rabiei, the causal agent of ascochyta blight (AB). In order to reduce the impact of this disease, novel sources of resistance are required in chickpea cultivars. Here, we screened a new collection of wild Cicer accessions for AB resistance and identified accessions resistant to multiple, highly pathogenic isolates. In addition to this, analyses demonstrated that some collection sites of Cicer echinospermum harbour predominantly resistant accessions, knowledge that can inform future collection missions. Furthermore, a genome-wide association study identified regions of the Cicer reticulatum genome associated with AB resistance and investigation of these regions identified candidate resistance genes. Taken together, these results can be utilised to enhance the resistance of chickpea cultivars to this globally yield-limiting disease.


2009 ◽  
Vol 89 (3) ◽  
pp. 515-516 ◽  
Author(s):  
B. Taran ◽  
T. Warkentin ◽  
S. Banniza ◽  
A. Vandenberg

CDC Corinne, a desi chickpea (Cicer arietinum L.) cultivar, was released in 2008 by the Crop Development Centre, University of Saskatchewan, for distribution to Select seed growers in western Canada through the Variety Release Program of the Saskatchewan Pulse Growers. CDC Corinne has a pinnate leaf type, fair resistance to ascochyta blight [Ascochyta rabiei (Pass.) Lab.], medium maturity, medium seed size and higher yield potential than Myles in the Brown and Dark Brown soil zones of the Canadian prairies. Key words: Chickpea, Cicer arietinum L., cultivar description, ascochyta blight


2005 ◽  
Vol 137 (2) ◽  
pp. 202-214 ◽  
Author(s):  
Christian Nansen ◽  
David K. Weaver ◽  
Sharlene E. Sing ◽  
Justin B. Runyon ◽  
Wendell L. Morrill ◽  
...  

AbstractThe wheat stem sawfly, Cephus cinctus Norton, is a major insect pest in dryland wheat (Triticum L. spp.; Poaceae) fields in the northern Great Plains of the United States and in southern regions of the prairie provinces of Canada. Field infestations by this pest commonly show a distinct “edge effect”, with infestation levels highest at the field edge and declining inwards. In this study, we characterized the edge effect of C. cinctus infested wheat fields in Montana at four locations in two separate years. "Infestation level" refers to the average proportion of wheat stems infested with C. cinctus in samples collected in a given wheat field. The gradual decrease in C. cinctus infestation towards the centre of wheat fields is referred to as the “infestation slope”, and it was presented as a proportion of infestation level at field edges. We showed that (i) for most of the fields bordering grassland or fallow wheat, a simple exponential decline curve provided a significant fit to the infestation slope; (ii) the infestation slopes in different fields and in different directions within fields were similar and appeared to be independent of the overall infestation level; and (iii) the relationship between infestation level and the proportion of samples infested followed an asymptotic curve, which indicates a high level of dispersal of ovipositing C. cinctus females. The general perception has been that the edge effect of C. cinctus infestation is a result of ovipositing C. cinctus females being both weak flyers and short-lived, but our results do not fully corroborate this perception. Currently, the only reliable way to detect C. cinctus infestations is to dissect individual stems and look for developing instars. However, this type of sampling is extremely time consuming and labor intensive and therefore impractical for wheat growers. Increasing the understanding of the spatial patterns in C. cinctus infestations is a first step towards development of an optimal sampling plan for this important field pest. Thus, the results presented are relevant for researchers involved in sampling designs and integrated pest management procedures for field pests. We discuss behavioral and evolutionary factors that may contribute to the edge effect of C. cinctus infestations.


2018 ◽  
Vol 10 (3) ◽  
pp. 195-198
Author(s):  
M. Koleva ◽  
Y. Stanoeva ◽  
I. Kiryakov ◽  
A. Ivanova

2005 ◽  
Vol 45 (10) ◽  
pp. 1291 ◽  
Author(s):  
T. T. Nguyen ◽  
P. W. J. Taylor ◽  
R. J. Redden ◽  
R. Ford

Cultivated chickpea germplasm collections contain a low frequency of ascochyta blight resistant accessions. This might lead to limitations on the future progress of chickpea breeding worldwide. In an effort to identify novel sources of resistance to ascochyta blight, 56 unique accessions, comprising 8 annual wild Cicer species, were evaluated under a controlled environment that was optimal for infection with an aggressive Australian isolate of Ascochyta rabiei (Pass.) Labrousse. The majority of wild Cicer accessions were either susceptible or highly susceptible to A. rabiei 21 days after inoculation; however, 11 accessions, of which 7 were Cicer judaicum, were resistant. The most resistant accession detected in this study, ATC 46934, together with accessions ATC 46892 and ATC 46935, which were resistant in this and another study, should be targeted for use in future interspecific resistance breeding programs.


1977 ◽  
Vol 57 (2) ◽  
pp. 389-395 ◽  
Author(s):  
A. TEKAUZ ◽  
K. W. BUCHANNON

The distribution in western Canada of three biotypes of Pyrenophora teres, the cause of net blotch of barley, was determined. Two of these produced typical net blotch symptoms but differed in virulence and were found throughout the prairies in 1974. The third, which produces spot-like symptoms, was found only in Manitoba and comprised half the total isolates. The incidence of net blotch was higher in fields of two-rowed than in six-rowed barley. Resistance to the three biotypes of P. teres was found in several barley lines when symptom expression and rate of conidial development on infected host tissue were compared. CI 9214 was superior to CI 5791, the resistance source used in some barley breeding programs.


2008 ◽  
Vol 70 (2) ◽  
pp. 188-197 ◽  
Author(s):  
Thomas W.D. Edwards ◽  
S. Jean Birks ◽  
Brian H. Luckman ◽  
Glen M. MacDonald

AbstractModelling of tree-ring δ13C and δ18O data from the Columbia Icefield area in the eastern Rocky Mountains of western Canada provides fuller understanding of climatic and hydrologic variability over the past 1000 yr in this region, based on reconstruction of changes in growth season atmospheric relative humidity (RHgrs), winter temperature (Twin) and the precipitation δ18O–Twin relation. The Little Ice Age (~ AD 1530s–1890s) is marked by low RHgrs and Twin and a δ18O–Twin relation offset from that of the present, reflecting enhanced meridional circulation and persistent influence of Arctic air masses. Independent proxy hydrologic evidence suggests that snowmelt sustained relatively abundant streamflow at this time in rivers draining the eastern Rockies. In contrast, the early millennium was marked by higher RHgrs and Twin and a δ18O–Twin relation like that of the 20th century, consistent with pervasive influence of Pacific air masses because of strong zonal circulation. Especially mild conditions prevailed during the “Medieval Climate Anomaly” ~ AD 1100–1250, corresponding with evidence for reduced discharge in rivers draining the eastern Rockies and extensive hydrological drought in neighbouring western USA.


2000 ◽  
Vol 53 ◽  
pp. 97-102 ◽  
Author(s):  
G. Ye ◽  
D.L. McNeil ◽  
G.D. Hill

This paper summarises existing studies of the genetics of resistance of lentils to Ascochyta blight and the genetic variation among pathogen populations with particular emphasis on the results from our programme Breeding methods are discussed Six pathotypes have been identified Resistance is mainly under the control of major genes but minor genes also play a role Current breeding programs are based on crossing resistant cultivars with high yield cultivars and multilocation testing Gene pyramiding exploring slow blighting and partial resistance and the use of genes from wild relatives will be the methods used in future


Sign in / Sign up

Export Citation Format

Share Document