Ogolla, James Arim (2005) Diversity of Plant Parasitic Nematodes Associated with Maize (Zea mays L.) and Integrated Control of Lesion Nematodes (Pratylenchus spp.). Masters thesis, Kenyatta University.
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Abstract
Up to 50% maize (Zea mays L.) yield losses in Kenya have been attributed to phytonematodes. Efforts to mitigate maize yield losses caused by nematodes have been hampered by inadequate knowledge on impact of nematodes on maize and lack of affordable nematode management strategies. The objectives of this study, therefore, was to determine diversity and density of phytonematodes associated with maize in smallholder farms in Kirinyaga and Embu districts, evaluate response of maize varieties (Pan5195, Pan5355, HB614, H627, H625, H513, Emapll and Phb) and legumes (Canavalia ensiformis L., Mucuna pruriens L., Lablab purpureus L. and Crotalaria ochroleuca G.) to lesion nematodes (Pratylenchus spp. Filipjev), to investigate the effect of inter-cropping maize with non-host legumes and the efficacy of organic soil amendments (C ensiformis, M pruriens and cattle-manure) against lesion nematodes. In addition, the study investigated the damage potential of varying lesion nematodes densities (1000, 2000 and 4000 nematodes per 2000 cnr' of soil) on the above maize varieties. All experiments on the above objectives except the later were inoculated at a rate of 1 nematode/g of soil. The nematode inoculum was obtained from farmers' field and multiplied on susceptible maize varieties in the greenhouse. In the greenhouse tests, maize and legume seeds were planted in pots containing autoclaved laterite soil, sandy loam mixed with 690 mg N kg' of soil. In addition, for efficacy test, amendments were applied at 135 g kg" of soil and 5.0 tonnes ha-1 for greenhouse and on-farm tests, respectively. Treatments were replicated 6 times and laid in Randomised Complete Block Design (RCBD). Twelve nematode genera (Pratylenchus, Paratylenchus, Meloidogyne, Tylenchus, Ditylenchus, Scutellonema, Tylenchorhynchus, Hemicycliophora, Tetylenchus, Heterodera, Trichotylenchus and Helicotylenchus) were found associated with maize in the study area. Pratylenchus was dominant genus both in soil and maize roots and caused up to 50% root necrosis (disease severity). Greenhouse test revealed that Pan5195 and H627 were tolerant to lesion nematodes. Conversely, the highest nematode inoculum density, 4000 significantly suppressed Phb, HB614, 513, Emapll, Pan5355 and H625 plant growth by up to 40%. The study indicated that C ensiformis and M pruriens were non-hosts while L. purpureus was tolerant to lesion nematodes. However, C ochroleuca was highly susceptible and its growth was suppressed by up to 36%. Intercropping maize with C ensiformis was more effective than M pruriens in suppressing nematodes and improving crop performance. Canavalia ensiformis significantly improved plant growth by up to 34%, reduced nematode soil infestation and disease severity by up to 70% and 26%, respectively. On-farm test revealed that inter-cropping Emapll, Pan5195 and H627 with C ensiformis significantly, increased maize grain yield by 190%, 29% and 22%, respectively. Mucuna pruriens significantly increased H627 grain yield by 12% but suppressed Pan5195 and Emapll grain yield by 79% and 40%, respectively. Efficacy test revealed that M pruriens and cattle-manure were equally effective against the nematodes. Results of greenhouse test, indicate that cattle-manure, C ensiformis and M pruriens significantly improved plant growth by up to 106%, 90% and 81%, respectively, and reduced nematode disease severity by up to 46%. In the onfarm experiment, cattle-manure and M pruriens significantly improved maize grain yield by up to 88% and 53%, respectively, and suppressed nematode population in soil by up to 68%. In addition, amending soil with cattle-manure, C ensiformis and M pruriens significantly reduced nematode disease severity by up to 70%.
| Item Type: | Thesis (Masters) |
|---|---|
| Subjects: | Q Science > Q Science (General) Q Science > QH Natural history > QH301 Biology Q Science > QR Microbiology |
| Divisions: | Africana |
| Depositing User: | Tim Khabala |
| Date Deposited: | 25 Jan 2018 12:53 |
| Last Modified: | 25 Jan 2018 12:53 |
| URI: | http://thesisbank.jhia.ac.ke/id/eprint/3198 |
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