Evaluation of Mustard (Brassica juncea L.) Hybrids against Alternaria Blight Incited by Alternaria brassicae under Artificial Inoculation Conditions
Manish Dhakar
Department of Plant Pathology, Rajmata Vijayaraje Scindia Agricultural University, Gwalior, 474002, India.
Rajni Singh Sasode
Department of Plant Pathology, Rajmata Vijayaraje Scindia Agricultural University, Gwalior, 474002, India.
Ravi Yadav
Zonal Agricultural Research Station, Rajmata Vijayaraje Scindia Agricultural University, Morena, 476001, India.
M K Tripathi
*
Zonal Agricultural Research Station, Rajmata Vijayaraje Scindia Agricultural University, Morena, 476001, India.
S S Tomar
Zonal Agricultural Research Station, Rajmata Vijayaraje Scindia Agricultural University, Morena, 476001, India.
Swati Singh Tomar
Zonal Agricultural Research Station, Rajmata Vijayaraje Scindia Agricultural University, Morena, 476001, India.
Jagendra Singh
Zonal Agricultural Research Station, Rajmata Vijayaraje Scindia Agricultural University, Morena, 476001, India.
Rajbabbar Jatav
Department of Plant Pathology, Rajmata Vijayaraje Scindia Agricultural University, Gwalior, 474002, India.
*Author to whom correspondence should be addressed.
Abstract
Alternaria blight is a destructive disease of Indian mustard caused principally by Alternaria brassicae. The present investigation evaluated 50 mustard hybrids for their reactions to the disease under artificial inoculation conditions during the 2025–26 Rabi season. The experiment was conducted in a randomised block design with two replications. Disease severity was assessed using a modified 0–9 rating scale, and percent disease intensity (PDI) was calculated for each hybrid. Disease reactions were classified according to the corresponding PDI ranges. None of the tested hybrids was immune or highly resistant. PDI ranged from 8.65% to 51.15%. Rohini × PAB-2017-22 recorded the lowest PDI (8.65%), whereas Krishna × PAB-2014-4, JM-1 × PAB-2014-7, and Bio-Y-SR × PAB-2014-4 recorded the highest PDI (51.15%). Five hybrids were classified as resistant, 21 as moderately resistant, 18 as susceptible, and six as highly susceptible. The resistant group comprised Rohini × PAB-2017-22, Vasundhara × PAB-2017-1, RVM-1 × PAB-2017-22, GM-1 × PAB-2017-18, and Rajat (PCR-7) × PAB-2014-18. The observed variation indicates that the evaluated hybrid combinations differ in their responses to Alternaria blight under uniform disease pressure. The resistant and moderately resistant hybrids provide preliminary material for further validation under controlled conditions and across seasons and locations before their use in resistance-breeding programmes.
Keywords: Alternaria blight, artificial inoculation, Brassica juncea, disease intensity, disease resistance, genotype screening, Indian mustard, percent disease intensity, resistant hybrids, susceptible hybrids