Inheritance of Early Leaf Spot Resistance in Different Generations of Groundnut (Arachis hypogaea L.) under Natural Epiphytotic Conditions
Kumar Sanu *
Department of Genetics & Plant Breeding, College of Agriculture, Gwalior, Rajmata Vijayaraje Scindia Krishi Vishvavidyalaya, Gwalior, Madhya Pradesh – 474002, India.
R. S. Sikarwar
Department of Genetics & Plant Breeding, College of Agriculture, Gwalior, Rajmata Vijayaraje Scindia Krishi Vishvavidyalaya, Gwalior, Madhya Pradesh – 474002, India.
Sanjeev Sharma
Department of Genetics & Plant Breeding, College of Agriculture, Gwalior, Rajmata Vijayaraje Scindia Krishi Vishvavidyalaya, Gwalior, Madhya Pradesh – 474002, India.
Supriya Singh
Department of Genetics & Plant Breeding, College of Agriculture, Gwalior, Rajmata Vijayaraje Scindia Krishi Vishvavidyalaya, Gwalior, Madhya Pradesh – 474002, India.
Sachin Shukla
Department of Genetics & Plant Breeding, College of Agriculture, Gwalior, Rajmata Vijayaraje Scindia Krishi Vishvavidyalaya, Gwalior, Madhya Pradesh – 474002, India.
Riya Mishra
Department of Genetics & Plant Breeding, College of Agriculture, Gwalior, Rajmata Vijayaraje Scindia Krishi Vishvavidyalaya, Gwalior, Madhya Pradesh – 474002, India.
Priya Giri
Department of Genetics & Plant Breeding, College of Agriculture, Gwalior, Rajmata Vijayaraje Scindia Krishi Vishvavidyalaya, Gwalior, Madhya Pradesh – 474002, India.
Diksha Khajuria
Division of Plant Breeding and Genetics, Sher-e-Kashmir University of Agricultural Sciences & Technology of Jammu, Jammu -180009, India.
Suraj Kumar
Regional Research Station, Madhopur, West Champaran, Dr. Rajendra Prasad Central Agricultural University, Pusa, Samastipur, Bihar – 848125, India.
*Author to whom correspondence should be addressed.
Abstract
Early leaf spot (ELS), caused by Cercospora arachidicola Hori, is a major foliar disease of groundnut that can cause considerable yield loss under favourable conditions. Understanding the inheritance of resistance is fundamental to developing resistant cultivars through conventional and molecular breeding approaches. The present investigation was undertaken to elucidate the inheritance pattern of early leaf spot resistance using six generations (P1, P2, F1, F2, BC1 and BC2) derived from contrasting resistant and susceptible parents at the Research Farm, Department of Genetics and Plant Breeding, RVSKVV, Gwalior, in a randomised block design (RBD) with three replications. Data were recorded from 20 plants per replication, i.e., 60 plants in total. Disease severity was assessed under natural epiphytotic conditions using the standard 1–9 disease rating scale at 30, 45 and 60 days after sowing. TG-86 and Nitya Harita maintained low disease scores throughout the assessment, whereas DH-245 and DH-257 showed a marked increase in disease severity and were susceptible at 60 DAS. Among the crosses, TG-86 × DH-245, TG-86 × DH-257 and Nitya Harita × DH-257 showed better resistance, with their F1 generations reflecting resistance. Their F2 generations also recorded low disease reactions, indicating the presence of resistant segregants. Nitya Harita × DH-245 showed a moderately resistant F1 response, while its F2 and BC1 generations recorded highly resistant reactions to ELS. TG-86 and Nitya Harita were identified as useful resistance sources, while promising crosses such as F2 by selfing (TG-86 × DH-257), BC1- (Nitya Harita × DH-245) × Nitya Harita and F2 by selfing (Nitya Harita × DH-245) may be utilised further in breeding programmes for the genetic improvement of groundnut for ELS resistance.
Keywords: Groundnut, early leaf spot, disease resistance, inheritance, segregating generations, natural epiphytotic conditions, resistant parents, backcross generations, disease severity, breeding populations