Resistance to Penicillium hirsutum Dierckx in garlic accessions. Correlation with the bulb allicin content.

CAVAGNARO, P.F.; CAMARGO, A.; PICCOLO, R; GARCÍA LAMPASONA, S.; BURBA, J.L.; R.W. MASUELLI

EUROPEAN JOURNAL OF PLANT PATHOLOGY

Año: 2005 p. 195 - 199

0929-1873

Garlic is an important and widely distributed crop used as a spice and for medicinal purposes. Among the factors affecting its quality and yield, blue mold –caused by Penicillium spp.- is responsible for economical losses in many countries. While pre-plant clove treatment with fungicides is the primary means controlling this disease, there is a need to identify and introduce host plant resistance for crop improvement. Allicin, present in garlic bulbs, has been suggested to have antifungal activity against some Penicillium species. This study was conducted to evaluate the response of garlic accessions against Penicillium hirsutum infection and to correlate this response with bulb allicin content. Twelve garlic accessions were inoculated with P. hirsutum Dierckx, and assayed at greenhouse and growth chamber experiments. Plant growth parameters and the fungal production of conidia were evaluated. Significant differences were found among the accessions. Accessions Castaño and Morado were most resistant whereas AR-I-125 and Fuego were always severely affected by the disease. Low correlation was found (r = 0.17) between allicin content and tolerance, indicating that allicin is not the main factor involved in the resistance against P.  hirsutum. The synthesis of a red pigment surrounding the fungal colonies in cloves from Morado, was observed. The possible roles of this clone-dependent reaction as well as the production of a cork-like tissue are discussed as defense responses.