Heterosis Assessment for Stem Rot Resistant Hybrids in Indian Mustard (Brassica juncea L.)

Abstract

Brassica juncea (L.) is a key oilseed crop that is extensively grown worldwide for edible oil and animal feed. However, various biotic and abiotic stresses, together with a narrow genetic base, keep productivity below the desired level, underscoring the need to expand the genetic base and utilise heterosis to develop superior cultivars with resistance or tolerance to major diseases. The present investigation was undertaken to evaluate standard heterosis for seed yield and its attributing traits among 50 diverse cross combinations developed during Rabi, 2025 and evaluated during Rabi, 2026, along with the zonal (Rohini) and national (Kranti) checks at the Research Farm, Zonal Agricultural Research Station, Morena, RVSKVV, Gwalior, M.P., India, using putative donors for stem rot resistance. Significant variability existed for yield and its attributing characters, with seed yield per plant ranging from 11.2 g for the cross L-6 × BC1F5 of Pusa Jai Kisan × Brassica napus 114 to 42.0 g for the cross Pusa Bold × F3 of Pusa Jai Kisan × Brassica napus 114. Strong hybrid vigour was evident in cross combinations such as Varuna × BC1F5 of Pusa Jai Kisan × Brassica napus 114, Sej-2 × BC2F1 of Pusa Jai Kisan × Brassica napus 114, and Shraddha × BC2F1 of Pusa Jai Kisan × Brassica napus 114, which showed high positive heterosis for yield and its component traits, including number of siliquae per plant, number of seeds per siliqua, 1000-seed weight, and earliness. The yield potential of these crosses was further supported by architectural traits, including longer racemes and a higher number of branches per plant. These results highlight the potential of targeted hybridisation to overcome current yield constraints. These promising cross combinations indicate that heterosis breeding may be used to improve yield in Indian mustard while incorporating resistance to Sclerotinia stem rot disease.