Evaluation of pearl millet (Pennisetum glaucum l) genotypes for resistance to head smut disease (Tolyposporium penicillariae bref.) in dry areas of Kenya

Abstract

Head smut caused by Tolyposporium penicillariae Bref, is a devastating fungal disease that cause up to 30% yield losses in pearl millet Pennisetum glaucum (L.) R.Br.). Pearl millet is the most drought tolerant cereal grown mainly by small scale farmers who cannot afford fungicides. Development of resistant genotypes offers the most economical means of head smut control however this depends primarily on the availability of sources of resistance. The study evaluated host plant resistance among fifty advanced pearl millet genotypes in two selected dry land sites (Koibatek and Marigat) in Kenya. Three experiments were performed to determine pearl millet genotypes that are high yielding and resistant to head smut. Experiment I, was done in the field in the two sites while experiments II and III were both carried out in the laboratory and glass house. Results from the field experiment showed that yield and disease severity were highly significant among the genotype (Fpr <0.001) with yield ranging from 1172-4122kgha-1. The high yielding genotypes were SDMV 90031, IP 8783, Shibe, ICMV 96603, ICMV221-1, IP 6791 and ICMV 221 Bristled. Genotypes, Shibe, SDMV 90031, IP 94014, IP8783 and SDMV 96603 IP 6791 were both resistance with the best yields. In experiment II, three isolates of head smut from major pearl millet growing areas (Koibatek, Makueni and Mbeere) were cultured in PDA and inoculated to 20 selected genotypes in a glass house at Egerton University. Data on the severity indicated that Makueni isolate was the most virulent with an average AUDPC (Area under Disease Progress Curve) of 108 followed by Mbeere and Koibatek isolates with AUDPC of 68 and 45 respectively. Genotypes ICMV 93771, IP 6791, Tsholotsho, Shibe, SDMV 90031, ICMV 96603, and ICMV 91450 exhibited resistance with the most virulent isolate. In experiment III all the 50 genotypes were inoculated with the most virulent isolate from Makueni. In conclusion genotypes SDMV 90031, IP 6791, ICMV 91450 and ICMV96603 are resistant and high yieding. Other most resistant genotypes were IP 8783, IP9946, ICMV 221-3, ICMV 91450, ICMV 88908, ICMV 94151 and IP 8783. The Commercial resistant checks ICMV 221 and KAT PM1 were resistant to the most virulent isolate from Makueni. All the above genotypes are recommended for further research an evaluation for relese as commercial varieties in Kenya . Key Words Drought tolerant; Disease severity; Economically viable; Sources of resistance; Virulent isolate.