Evaluation of Sorghum Genotypes Compatibility with Fusarium oxysporum under Striga Infestation

Abstract

ABSTRACTCombined use of host resistance and Fusarium oxysporum as a biocontrol agent may provide enhanced management of Striga hermonthica (Delile) Benth. in sorghum [Sorghum bicolor (L.) Moench]. The objective of this study was to identify sorghum genotypes compatible with F. oxysporum and to determine the potential of this biocontrol agent for controlling Striga. Fifty sorghum genotypes were evaluated in the greenhouse in Striga‐infested soils with and without inoculation by F. oxysporum. A supplementary laboratory study was conducted to investigate the growth and proliferation of F. oxysporum in the soil and sorghum roots. Data were recorded on crop growth parameters, Striga incidence and colonization, and the persistence of F. oxysporum in the soil and on plant roots, using samples taken at 45 and 60 d after planting. Inoculation with F. oxysporum significantly shortened days to maturity compared to noninoculated plants. Plant height, biomass, panicle length, and seed yield per plant were higher in F. oxysporum treated pots. Striga emergence was delayed and vigor and overall incidence of the parasite was significantly reduced in Fusarium‐treated pots. The number of Fusarium colony forming units obtained from soil and plant samples were significantly different between genotypes. Three principal components (PCs) contributed to 67.31% of the total variation among the genotypes. Principal component 1, PC2, and PC3 contributed 27, 23, and 18%, respectively, to the total variance. Days to Striga emergence and Striga count and height correlated with PC1 while sorghum panicle length and plant height with PC2 and days to sorghum flowering and maturity with PC3. Thus, 12 promising sorghum lines were identified with farmer‐preferred agronomic traits and with F. oxysporum compatibility. This result is valuable in the development of Striga control in sorghum through integration of host resistance and F. oxysporum inoculation.