ABSTRACT

A total of 19 Open pollinated maize (Zea mays L.) genotypes were used in two field experiments to evaluate their tolerance to acid Soil (Low pH) conditions of the humid rainforest agro-ecological zone of South eastern Nigeria in 1998 and 1999 seasons. Randomized complete block design (RCBD) was used as the layout in both years and Bende White — a Local tolerant variety was used as a check. Of the 19 genotypes screened in the field using 20 and 26 attributes in 1998 and 1999 seasons respectively seven of the maize genotypes performed better than the check in both years, based on grain yield, adaptive features and other yield attributes. The genotypes included; ILL Comp 4CL, TZL Comp 4DMRSR, TZL ComP 3X4, AK 96 DMR-LSRW, TZBR [Id. 3C2, DMR-LSRW, and TZPB —SRW. Heritability and variability studies revealed that environment factors asserted greater influence on some of the quantitative characters studied in 1998 and 1999. Most of the agronomic characters had low heritabilities in both years except days to 50% tasselling and silking, Cob length and ear diameter that had moderately h!gh values of 57.7, 55.5, 45.7 and 55.7%, respectively in 1998 season. Multiple regression studies revealed that five out of the Sixteen agronomic characters studied contributed significantly to grain yield with fresh ear weight and ear diameter being major yield determinants in both years. Partial Correlation studies, however indicated that two )f the traits contributed positively and significantly to grain yield in 1998 while four traits contributed to grain yield in 1999 season. Path co-efficient analysis made on selected yield related characters in 1998 and 1999 seasons revealed that fresh ear weight and shelling percentage were consistent in their direct and indirect contributions to yield in both years. These two traits are, therefore, very important components of grain yield and should be given high weightage in any selection process aimed at improving grain yield in maize.