Development of novel genotypes of peanut with resistance to stem rot, large pod and seed

Stem rot caused by Agroathelia rolfsii (syn. Sclerotium rolfsii ) is one of the major biotic constraints to peanut production in many countries, particularly under high temperature and humidity conditions. Developing disease-resistant cultivars represents a more sustainable strategy. To generate peanut germplasm integrating stem rot resistance and elite yield traits, this study utilized a recombinant inbred line (RIL) population, consisting of 242 lines, derived from a cross between Zhonghua 212 (medium-seeded, resistant parent), and Zhonghua 21 (large-seeded, susceptible parent). A multi-environment evaluation was conducted for disease resistance profiling in the fields with artificial inoculation, and for yield-related traits assessment. The results indicated that twenty-two RIL lines exhibited consistent moderate resistance across all tested locations. Fifty RILs consistently expressed large pod (100-pod weight >180 g) and large seed (100-seed weight > 80 g) phenotypes in two environments. Three elite RIL lines (BJF66, BJF119 and BJF137) combined moderate resistance with superior pod/seed traits, providing valuable genetic sources for breeding programs targeting both disease resistance and productivity. This study established a foundational germplasm pool for advancing stem rot resistant, high-yielding peanut varieties, aligning with sustainable agricultural practices to mitigate A. rolfsii threats.