Abstract

Ayodele Adesina Adegbite

Field trials were conducted in 2008 and 2009 to investigate the reaction of 13 varieties of maize (Zea mays L.) to natural infestation of root knot nematode, Meloidogyne incognita at the Institute of Agricultural Research and Training, Obafemi Awolowo University, Moor Plantation, Ibadan, Nigeria under field conditions. Used maize varieties were ART/98/SW6-0B, BR-9928 DMR, BR-9943 DMR, DMRESR-White, DMR-ESR-Yellow, DMR-LSR-White, DMR-LSR-Yellow, ILE-1-OB, Obatampa, Suwan-1-SR, TZSR-Y-1, TZPB-SRW and Western Yellow. They were obtained from IAR&T, IITA, Ibadan and Ghana. Ten weeks after planting, 15 randomly selected plants per variety were assessed for root galling. Data were also collected on plant height, ear height, stem girth, days to 50% silking, days to maturity and yield (kg/ha). According to study results, gall index and nematode reproduction factor varied significantly among the maize varieties; ART98 SW6-OB recorded the tallest height of 200 and 195 cm respectively in 2008 and 2009 while the least (170 cm) was recorded for TZPB-SRW in the two cropping seasons. Stem girth ranged from 6.3 to 5.0 cm in 2008 and 6.2 to 4.9 cm in 2009. Ear height ranged from 72.5 to 65.5 cm in 2008 and from 70.5 to 64.5 cm in 2009. Days to 50% silking ranged from 60 to 48 in 2008 and ranged 59 to 48 in 2009. Days to maturity ranged from 120 to 70 days in the two cropping seasons. Grain yields ranged from 3650 to 2025 kg/ha in 2008 and ranged from 4125 to 2625 kg/ha in 2009. Based on gall index ratings, ART98SW6-OB and ILE1-OB were resistant to M. incognita, BR-9928 DMR, BR-9943 DMR, DMR-ESR-W and DMR-ESR-Y, totally 4 varieties, were found as tolerant, DMR-LSRW and DMR-LSR-Y varieties were found as hypersusceptible while Obatampa, Suwan 1-SR, TZSR-Y-1, TZPB-SRW and Western Yellow were found as susceptible to M. incognita.