Screening for Resistance Sources in Local and Exotic Hot Pepper Genotypes to Fusarium Wilt (Fusarium oxysporium) and Associated Quality Traits in Ethiopia

Abstract

Fifty-four hot pepper germplasm (49 local accessions and 5 AVRDC genotypes) were evaluated for resistance to fusarium wilt in a greenhouse at Melkassa Agricultural Research Centre in Ethiopia. A completely randomized design with three replications was used. Each local accession was also analyzed for associated quality traits of capsaicin and oleoresin content. The overall results indicated that disease incidence ranged from 8 (PBC-731) to 100% for Acc-15. Most local collections exhibited higher disease incidences percent than AVRDC genotypes with an overall mean DI <25% of Fusarium wilt. Among the 49 local accessions, however, only two accessions were found resistant (1-10%) while three were moderately resistant (11-20%). Assessment of the same accessions for resistance to the disease using severity index (SI) showed that 11 accessions and genotypes were found resistant (<10% DSI) whereas nine genotypes moderately resistant (10-20% SI), 10 genotypes were moderately susceptible (21-40% SI), four accessions were found susceptible (41-60%) and the rest 20 accessions were highly susceptible >60%. Based on severity rating (1-5 scale), two accessions (Acc-39 and PBC-731) were highly resistant to wilt with severity ratings of 1 and 14 accessions were found resistant with severity rating scale of 2 whereas 38 accessions were susceptible with severity scale of >3. Capsaicin content percentage ranged from 0.16-0.55%, and heat unit ranged 26372 to 88775 SHU, for Acc-32 and Acc-24, respectively. Oleoresin content in international color unit and ASTA value ranged from 32,800 to 118,840 cu and 82-296 ASTA with an overall mean of 69,704 ICU and 172 ASTA value. The highest color quality colors of greater than 250 ASTA was exhibited by 10 accessions (Acc-4, Acc-5, Acc-6, Acc-7, Acc-24, Acc-27, Acc-33, Acc-34, Acc-39 and Acc-31). This study identified resistance accessions with desirable qualities among the 49 local accessions. These materials also had good wilt resistance potential and could be used as source parents in the future hybridization and for simultaneous selection for Fusarium wilt resistance and high processing quality traits in hot pepper improvement program.