Nitrogen Use Efficiency and Grain Yield in a Diallelic Cross of Maize Populations

Bello O B,Abdulmaliq S Y,Ige S A,Azeez M A,Mahmud J,Afolabi M S

doi:10.5923/j.plant.20120203.08

Abstract

The high cost of inorganic fertilizer in West and Central Africa has necessitated an investigation into the nitrogen optimum fertilizer rate for profitable maize production. The performance of ten early open pollinated varieties (OPVs) and their F1 hybrids for grain yield and nitrogen use efficiency (NUE) was assessed, and productive cultivars under low N fertilizer regimes were also quantified. The trials (ten OPVs and their F1 hybrids) were set up in a split plot arrangement with three N fertilizer levels (0, 45 and 90 kg N ha-1) as main plot and the genotypes as sub-plot. Each plot was four-row, laid out in a randomized complete block design (RCBD) of four replications. Field experiments were conducted at the teaching Research (T and R) farm of the University of Ilorin, in the southern Guinea savanna of Nigeria. Planting was carried out during the growing season on 20th July, 2005 and 2nd July, 2006. Ten open pollinated maize cultivars were crossed in a half diallel to generate 45 F1 hybrids during 2004 and 2005 growing seasons. Observed agronomic characteristics were grain yield, establishment plant count, days to 50% tasselling and silking as well as plant and ear heights. All observed characteristics amongst all the genotypes during growing season in 2005 were better than those in 2006. Expressions of all characteristics in the selected hybrids including the grain yield were relatively higher than the OPVs. The total increase in grain yield was 1.72 t ha-1 and 1.95 t ha-1 for OPVs and hybrids respectively on application of 90 kg N ha-1 over no N-application. However, nitrogen use efficiency (NUE) was optimum at 45 kg N ha-1 in both groups. Grain yield and NUE correlated positively with growth characters measured except for days to 50% silking. Higher genetic gains were recorded for plant and ear heights. The hybrids Acr 90 Pool 16-Dt Ã Ak 95 Dmr-Esrw, Tze Comp4 C2 Ã Ak 95 Dmr-Esrw and Tze Comp 4 C2 Ã Tze Comp 3 C2 had higher grain yield with superiority for NUE (P< 0.05). It suggested that the hybrid combinations can further be tested under commercial growing conditions or can be introgressed with other released cultivars to develop low N-tolerant varieties in the in the Nigeriaâs savanna ecologies.

Highlights

Maize (Zea mays L.) is an important staple food crops and provides bulk of raw materials for the livestock and many agro-allied industries in the world[1,2]
Importance of maize production has been widely publicized among farmers of Nigeria
Despite fertilizers recommendations (60 to 120 kg N ha-1) for resource poor farmers in the West Africa moist savannah[2,3], less than 20 kg N ha-1 used in Nigeria was considered grossly inadequate and 50 kg nutrient ha-1 fertilizer use was recommended across sub-Saharan Africa by African Heads of States at the Fertilizer Summit held in 2006 at Abuja, Nigeria

Summary

Introduction

Maize (Zea mays L.) is an important staple food crops and provides bulk of raw materials for the livestock and many agro-allied industries in the world[1,2]. The farmers have been indoctrinated with the belief that required amount of inorganic fertilizers need to be applied for maximum performance of hybrid maize and good economic returns. Development of early maturing maize cultivars that remain productive under low N fertilizer farming system, consistent with the farmers’ technologies is a prerequisite to improving adoption of new varieties without increasing production cost in this agro-ecology. This may eventually enhance economic returns of the resource-poor farmers with the proviso that the reductions in fertilizer expenditures are greater than the value of any reduction in saleable maize, resulting from reduced N fertilizer usage. Chemical characteristics Exchangeable Ca2+ (Cmol kg -1) Exchangeable Mg2+ (Cmol kg -1) Exchangeable Na+ (Cmol kg -1) Exchangeable K+ (Cmol kg -1) Total acidity H++ (Cmol kg -1) Cation exchange capacity (Cmol kg -1)

Materials and Methods

Soil Analysis

Conclusions