Studies on Variability Among Alternaria burnsii Uppal Patel and Kamat Isolates Causing Blight of Cumin in Rajasthan and its Management

Abstract

newline The studies on variability among Alternaria burnsii (Uppal, Patel and newlineKamat) isolates causing blight of cumin in Rajasthan and its management were newlinecarried out at the Department of Plant Pathology and Instructional Farm, Rajasthan newlineCollege of Agriculture, Udaipur during the Rabi seasons of 2022-23 and 2023-24. newlineCumin blight disease is highly destructive across all cumin-growing areas of Rajasthan. newlineThe research was aimed to assess the disease intensity, cultural and morphological newlinecharacteristics, pathogenic and molecular variability of the pathogen, host plant newlineresistance, impact of various environmental factors, and development of integrated newlinemanagement approach through the use of new generation fungicides, neem newlineformulations and bio-agents. newlineDistinct variations in symptoms of cumin blight were observed in diseased newlinesamples collected from major cumin-growing districts of Rajasthan during Rabi 2022- newline23 and 2023-24. Pure culture of different isolates of Alternaria burnsii were obtained newlinefrom diseased samples collected from cumin growing areas of Barmer, Jodhpur, Jaipur, newlineNagaur, Jaisalmer, Ajmer, Udaipur, Jalore, Pali and Sirohi districts. The blight disease newlineintensity was ranged from 20.16% to 52.33%, with the maximum (52.33%) from newlineBhinmal (Jalore) and minimum (20.16%) from Sheoganj (Sirohi). The fungus newlineAlternaria burnsii, was isolated, purified, and its pathogenicity was confirmed. newlineTen isolates of Alternaria burnsii showed distinct variations in their cultural, newlinemorphological, pathogenic and molecular characteristics. The isolates, AltJl1 and newlineAltPa1 exhibited maximum sporulation (13.66×103/mm2 and 13.17 ×103/mm2), with newline89.70 mm and 86.13 mm colony diameters, respectively. The isolate AltAj1 exhibited newlinethe longest spores, with a length of 50.40 and#956;m and width 17.67 and#956;m followed by AltPa1 newlinewith a length of 48.73 and#956;m and with a width of 17.36 and#956;m. The pathogenic nature of ten newlinedifferent isolates of Alternaria burnsii was tested on cumin variety GC-4. Among the isolates, AltJl1 (78.60 PDI) was f