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Resistance

Evaluation of Tolerance to Septoria Leaf Blotch in Spring Wheat. Oded Ziv, Division of Mycology and Plant Pathology, Department of Botany, Tel Aviv University, Israel; Zahir Eyal, Division of Mycology and Plant Pathology, Department of Botany, Tel Aviv University, Israel. Phytopathology 66:485-488. Accepted for publication 29 September 1975. DOI: 10.1094/Phyto-66-485.

Differential loss in yield components of five spring wheat cultivars to Septoria leaf blotch epidemics as compared to fungicide-protected plants served as the basis for evaluation of tolerance. Yield and kernel weight furnish better estimates of tolerance to leaf blotch than grain number per head. In vulnerable wheat cultivars, lateral tillers sustained greater yield reductions than did the central tiller. Enhanced tillering possibly had a negative effect on yield in severe leaf blotch epidemics. The dwarf cultivar Bet-Dagan 131 exhibited yield and kernel weight reductions of about 40%, whereas the semi-dwarf cultivars manifested lower losses. The tolerant wheat cultivar Miriam, under leaf blotch severity equivalent to that of the other semi-dwarf cultivars, maintained a low level yield reduction similar to those attained by the moderately resistant cultivar Yafit. Under severe leaf blotch epidemics, vulnerable wheat cultivars with low 1,000-kernel weight are at a distinct disadvantage over agronomically similar cultivars with large grains.