COMPARISON OF LATE BLIGHT RESISTANCE AND YIELD OF POTATO VARIETIES

Growing more resistant potato varieties is one of the most effective strategies to control late blight, to protect potato yield and to prevent harming the environment. The main aim of our study was to identify potato varieties with higher resistance to late blight and which were high yielding in Estonian conditions and suitable for organic farming. During the three-year trial, twelve potato varieties were tested at the J?geva Plant Breeding Institute (PBI) in 2010–2012. Foliage late blight (Phytophtora infestance (Mont) de Bary) and yield were estimated. First infection of late blight occurred in different times during the trial years. The three-year average infection level indicated that early varieties ‘Arielle’, ‘Impala’ and ‘Princess’ were more damaged than other varieties in the first estimation. Late varieties ‘Ando’, ‘Anti’, ‘Juku’ and ‘Sarme’ had higher late blight resistance. Their foliage damage remained less than 30% in the last estimation. The new medium variety ‘Teele’ had a lower infection rate than other medium varieties and did not significantly differ from late varieties. Based on these data, late varieties, early variety ‘Maret’ and medium variety ‘Teele’ can be considered suitable for organic farming. The new variety ‘Teele’ had the highest threeyear average tuber yield (52.8 t ha-1). Varieties ‘Impala’, ‘Princess’ and ‘Secura’ had significantly lower yield. Yield loss of these varieties might have been caused by higher late blight infection during trial years.