ISSN 1392-3196 / e-ISSN 2335-8947
Zemdirbyste-Agriculture, vol. 106, No. 4 (2019), p. 367–376
DOI 10.13080/z-a.2019.106.047

The evaluation of disease resistance of flax genotypes in relation to environmental factors



Fungal diseases are one of the limiting factors of flax (Linum usitatissimum L.) production in variable environmental conditions. The expansion of fungal diseases depends on the plant resistance, pathogen population’s ability to overcome this resistance and plant growth conditions. This study is aimed to estimate the flax resistance to fungal diseases in relation to environmental factors under the field conditions and identify the most promising accessions for plant breeding. A total of 24 fibre flax genotypes of local origin were investigated. The flax genotypes with different resistance to the most common diseases were identified using the area under the disease progress curve (AUDPC) for plants and resistance index (RI): in the growing season with high humidity there were identified the genotypes that were more susceptible to wilt (caused by Fusarium oxysporum f. sp. lini), pasmo (caused by Septoria linicola) and anthracnose (caused by Colletotrichum lini), and in the growing season with drier conditions there were identified the genotypes that were more susceptible to stem break, browning of flax (caused by Polyspora lini), powdery mildew (caused by Oidium lini) and fusarium browning (caused by Fusarium spp.). The highest incidence of the causal agents Fusarium spp. and Colletotrichum lini on the flax seeds was identified in high humidity conditions. The most valuable flax genotypes S13/5-7/5-93, S64-17-93, T11-13/3-1-94 and L11-11/11-97 exhibited relatively high complex resistance to diseases and high yield compared to the standard cultivar ‘Vega 2’. The genotype ‘Rezeknes’ exhibited higher resistance to the powdery mildew at the seedling stage and complete resistance at the adult plant stage compared to all accessions.

Key words: breeding, causal agents of diseases, Linum usitatissimum, susceptibility.

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