Effects of host resistance on maturation of Leptosphaeria maculans and L. biglobosa (cause of phoma stem canker) in Brassica napus (oilseed rape)

Siti Nordahliawate Sidique, Yongju Huang, Avice Hall, Bruce Fitt

Research output: Contribution to conferenceAbstract


Phoma stem canker is an important disease in most countries growing
oilseed rape. The sexual spores of the pathogens (Leptosphaeria
maculans and L. biglobosa) produced in pseudothecia on infected winter
oilseed rape stubble in autumn are the most important inoculum for
infection of newly emerged crops. We investigated effects of cultivar
resistance and environmental conditions (precipitation and temperature)
on maturation of pseudothecia on stem debris. Stems of nine winter
oilseed rape cultivars with different combinations of resistance (R) genes
and quantitative resistance (QR), including a susceptible cultivar Drakkar
with no known resistance, were collected after harvest in 2011 and 2012
from Rothamsted. They were then incubated under natural conditions at
the Bayfordbury field station, University of Hertfordshire. The results
indicate that pseudothecial maturation of the susceptible cultivar
Drakkar and cultivars Adriana (Rlm 4 + QR), ES-Astrid (QR) and Excel (Rlm
7) differed between autumn 2011 and 2012. There were differences
between summer 2011 and 2012 in severity of phoma stem canker in
the field experiment at Rothamsted, which is probably a reflection of the
very low rainfall in September 2011. Previous work has shown that the
rate of pseudothecial development is dependent on rainfall. In 2011,
there were few differences between cultivars but maturity was delayed.
However in 2012, pseudothecia matured much earlier and faster on
Drakkar than on the other cultivars (P < 0.05). This has implications for
the subsequent severity of stem canker. The impact of cultivar resistance
on the maturation of pseudothecia and also the possibility that L.
maculans retards the development of pseudothecia from L. biglobosa
need further investigation.
Original languageEnglish
Publication statusPublished - 2013
EventBritish Society for Plant Pathology - UK, United Kingdom
Duration: 17 Dec 2013 → …


ConferenceBritish Society for Plant Pathology
Country/TerritoryUnited Kingdom
Period17/12/13 → …


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