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SESSION 4: GENETICS OF HOSTS – PLANT RESISTANCE TO FUSARIUM,
VARIETY DEVELOPMENT
P110 - Identification and characterization of new
resistant accessions to Fusarium oxysporum f. sp.
pisi within a Pisum spp. germplasm collection.
M. Bani, D. Rubiales, N. Rispail.
Institute for sustainable agriculture – CSIC, Alameda del obispo, Avda. Menendez Pidal s/n,14080
Cordoba Spain.
E-mail: mustapha.bani@gmail.com
Fusarium oxysporum f. sp. pisi (Fop) is an important pathogen of field pea (Pisum
sativum). At present four races of Fop have been described, races 1, 2, 5 and 6.
Among them, Races 1 and 2 occur worldwide. The constant evolution of the
pathogen drives the necessity to broaden the genetic basis of resistance
to Fop. To achieve this, it is important to have a large germplasm collection
available and an accurate and efficient method for disease assessment. In this
study we searched for new sources of resistance to Fop races 1 and 2 in
a Pisum spp. germplam collection. Different methods of disease assessment
coupling disease incidence, disease rating over time and its related area under
the disease progression curve (AUDPC) were assessed to accurately evaluate
Fusarium wilt disease in a controlled environment. The results of this screening
revealed large variability in the response of the different accessions to Fop race 2
ranging from resistance to susceptible, indicating the quantitative nature of the
resistance to Fop race 2 in this Pisum spp. collection. On the other hand, the
response to Fop race 1 revealed a qualitative distribution, confirming the
monogenic resistance of our genotypes to Fop race 1. Two independent
repetitions of the inoculation experiments indicated that the scoring method was
robust and reproducible and confirmed the highly resistant phenotypes of nine
accessions to both races of Fop. The incorporation of these sources of resistance
to breeding programmes will contribute to improved Fop resistance in pea
cultivars. The characterization of resistance mechanisms acting within selected
resistant accessions by histological methods indicated that, in all resistant
characterized accessions, the progression of the pathogen is blocked in the basal
part of plant suggesting that the main resistance mechanisms act at the root and
crown level.
Keywords: Fusarium oxysporum, Pisum sativum, resistance mechanism, genetic
resistance
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