A novel hydroponic approach for efficient screening and rapid phenotyping for identification of Fusarium wilt resistance in brinjal (Solanum melongena l.) and wild Solanum species

Abstract

Fusarium wilt, caused by Fusarium oxysporum f. sp. melongenae (Fomg), has emerged as a serious disease limiting brinjal productivity. Soil-borne nature of the pathogen, limited reproducibility and environmental variability complicate the use of the laborious traditional screening methods for resistance to Fusarium wilt in breeding programs. To facilitate reliable screening and rapid phenotyping, we resorted to a novel hydroponic approach. In this study, 90 brinjal genotypes, including diverse cultivated and wild accessions, were grown in Hoagland solution and inoculated with Fomg, isolated from a Fusarium wilt-endemic field at the host institute. Disease indices (DI), area under disease progress curve (AUDPC) and area under disease progress stairs (AUDPS) were used to identify resistant genotypes and study disease progression. Host phenotypic trait assessments and histopathological studies were also used to characterize resistant sources. Five genotypes, namely BR-40-7, Pink, Bouldar, S. sisymbriifolium, and S. torvum were found immune to Fusarium wilt, while fifteen genotypes each were found highly resistant and resistant to the disease. Genotypes immune to the disease were asymptomatic. Highly resistant genotypes were late-wilters, while the resistant genotypes were slow-wilters. Highly susceptible genotypes exhibited early, rapid and severe wilting. Resistant genotypes exhibited superior root and shoot development compared to susceptible genotypes. The broad applicability of the hydroponic screening method to diverse plant species and root pathogens underscores its potential to address critical challenges in agriculture. This study is the first to use Fusarium-specific screening of germplasm in hydroponic brinjal and wild Solanum cultures.