Development of nematode resistance maize varieties by diallel mating in Owerri, rain-forest agro-ecology of Nigeria
The study was conducted in 2014 and 2015 cropping season at the Centre for agricultural research and extension (CARE) of Federal University of Technology, Owerri (FUTO) located at latitude 050 27‖ N and longitude 070 O2‖ E within the rain forest agro-ecology of Nigeria; to assess the tolerance level of maize accessions to natural field infection of root not nematode (Meloidogyne incognita), and develop F1 progeny from Diallel mating of superior lines for subsequent evaluation for nematode resistance. A randomized complete block design (RCBD) was used with three replications. The results of the experiment show significant variation at (p = 0.05) on number of days to maturity, leaf area, plant height, and nematode count. Based on nematode count and severity level, accessions, Amiacha, Iduma, Isiochi, Nwaba White Nkalagu, Egbuonwa, Mkpanmkpa, and Nwaba white Nwadakpo were tolerant to root – knot nematode. Four accessions, Iduma, Amiacha, Isiochi, and Nwaba White Nkalagu exhibited the best values of the nematode tolerance component and were selected and used in full diallel mating to produce 16. F1 hybrid. Correlation studies show that nematode count is positively and significantly correlated with days to 50% tasseling (r =0.464**) and plant height (r = 0.387**) but negatively correlated with days to maturity.
Key Words: Maize, Nematode, Diallel mating, Resistance and accessions