Grain discoloration in different genotypes of durum wheat (Triticum durum L.) in Argentina: associated mycobiota and peroxidase activity

CIPOLLONE, MARÍA JOSEFINA; MOYA, PAULINA; MARTÍNEZ, IVÁN ; MARIO CARLOS NAZARENO SAPARRAT; SISTERNA, MARINA

Journal of Plant Protection Research

Polish Academy of Sciences, Committee of Plant Protection

Año: 2020 vol. 60 p. 14 - 20

1427-4345

Wheat grain discoloration, a worldwide disease that lowers grain quality and decreasesgrain yield, does not have a single etiology. It has been proposed that it is a consequence ofan abiotic mechanism, a response to environmental conditions or enzymatic activity. It hasalso been suggest that it is a biotic mechanism, a fungal infection principally by Alternariaspp. and Bipolaris sorokiniana. The present work was carried out to analyze the possibleetiology of this disease in nine durum wheat genotypes from two localities of southernBuenos Aires province (Argentina) on two sowing dates. Incidence (percentage of graindiscoloration) was recorded and mycobiota associated with this pathology was registeredfollowing ISTA rules. Peroxidase activity in an extract obtained from grains belonging togenotypes of the locality that showed the highest incidence was measured.The incidence among genotypes, localities and sowing dates varied, although the genotypeswith the higher and lower values of incidence were the same for all the variablestested. The fungus Alternaria spp. was isolated the most frequently followed by Fusariumspp., while Bipolaris sorokiniana was found the least frequently. Peroxidase activity showedthat all the treatments had similar levels of enzymatic activity, but there was no clear differentiationbetween controls either between genotypes with the lowest or the highestincidence values. This suggests that peroxidase activity did not have a clear relationshipwith grain discoloration. In this research, it is presumed that fungal infection is the maincause of this disease.