A chloride-deficient leaf spot syndrome of wheat

• Published in: Soil Science Society of America journal Vol. 61; no. 1; pp. 176 - 184
• Main Authors: Engel, R.E, Bruckner, P.L, Mathre, D.E, Brumfield, S.K.Z
• Format: Journal Article
• Language: English
• Published: Madison, WI Soil Science Society of America 01-01-1997; American Society of Agronomy
• Subjects: ABONOS; Agronomy. Soil science and plant productions; APPLICATION RATES; Biological and medical sciences; CARACTERISTICAS DEL SITIO; CARENCE MINERALE; CHLORE; CHLORIDES; CHLORINE; CHLORURE; CLORO; CLORUROS; CULTIVARS; CULTIVOS DE INVIERNO; CULTURE D'HIVER; DEFICIENCIA DE MINERALES; Deficiencies. Phytotoxicity of elements. Salinity; Disease; DOSE D'APPLICATION; DOSIS DE APLICACION; ENGRAIS; FACTEUR LIE AU SITE; FERTILIZERS; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; LEAF SPOTTING; MANCHAS; MINERAL DEFICIENCIES; MONTANA; NUTRICION DE LAS PLANTAS; NUTRITION DES PLANTES; Physiological diseases. Varia; Phytopathology. Animal pests. Plant and forest protection; PLANT NUTRITION; PROPICONAZOL; PROPICONAZOLE; SINTOMAS; SITE FACTORS; Soil-plant relationships. Soil fertility. Fertilization. Amendments; SPOTS; SYMPTOME; SYMPTOMS; TACHE; TRITICUM; TRITICUM AESTIVUM; VARIEDADES; VARIETAL SUSCEPTIBILITY; VARIETE; VARIETIES; Wheat; WINTER CROPS; Montana; United States; North America; America; Pacific Northwest; Monocotyledones; Deficiency; Nutrition disorder; Etiopathogenesis; Plant leaf; Leaf spotting; Bioinorganic chemistry; Inorganic element; Cereal crop; Syndrome; Necrosis; Inorganic anion; Sensitivity resistance; Gramineae; Mineral fertilization; Chlorides; Winter crops; Angiospermae; Spermatophyta; Lesion; Soil plant relation; Triticum aestivum; Physiological disorder; Cultivar
• ISSN: 0361-5995; 1435-0661
• DOI: 10.2136/sssaj1997.03615995006100010026x

A leaf spot complex that results in tissue necrosis and whose origin is unknown frequently damages selected winter wheat (Triticum aestivum L.) cultivars in Montana and neighboring regions. This study was undertaken to determine leaf spot origin (physiologic or pathogenic), cultivar susceptibility, and response to Cl nutrition. Winter wheat studies at seven sites (1993-1995) compared cultivars (Redwin, Tiber, CDC Kestrel, Manning, Stephens, Sierra, and Promontory), propiconazole (1-[[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl]methy l]-1H -1,2,4-triazole) fungicide treatments, and multiple Cl fertilizer rates (0-90 kg ha-1). Chlorotic or necrotic lesions developed at all sites, but not all cultivars were affected similarly. CDC Kestrel was the most susceptible cultivar. Flag leaf spot severity (portion of tissue area affected) was as great as 40% in this cultivar. Redwin, Sierra, and Promontory were the next most susceptible cultivars, followed by Stephens and Manning. Tiber, a variant line row selection of Redwin, was leaf spot tolerant. Multiple propiconazole applications had no effect on leaf spot severity, and infectious organism(s) could not be isolated from symptomatic tissue. Thus, leaf spot origin was probably physiologic and not infectious. Chloride fertilization (11-22 kg ha-1) greatly suppressed or eliminated leaf spotting, and increased yield in one or more cultivars at six of seven sites (up to 998 kg ha-1). Physiologic leaf spot occurrence and severity in affected cultivars was linked to inadequate Cl nutrition, and a possible osmotic imbalance in leaf mesophyll cells. Damage was usually minor when whole-plant Cl at head emergence was greater than or equal to 1.0 g kg-1. Leaf spot damage increased exponentially as plant Cl dropped below this concentration. The name Cl-deficient leaf spot syndrome is proposed to describe this phenomenon in wheat