Evaluation of eggplant (Solanum melongena L.) parental varieties against their hybrid progenies and responses to N-fertilizer doses and dosing options on well-drained humid tropical soil

Abstract

Assessment of phenotypic variability is crucial to progress in plant breeding. We evaluated 19 varieties of eggplant (Solanum melongena L.) comprising five parents and 14 hybrid progenies on a coarse-textured soil in southeastern Nigeria. All entries differed in the agronomic traits considered. Six weeks after transplanting (WAT), Kaduna3 and Iyoyo were the shortest and tallest varieties, respectively, with Kaduna3 also showing the lowest values of all other growth traits. Ogbojioroke (local variety), with the most branches/leaves and nodes/internodes, took the shortest time to 50% flowering/fruiting while Kaduna3 × Iyoyo (F₄) took the longest. Ogbojioroke had the most fruits (1,716) and Kaduna3 the fewest (1.30) per 3 m² plot. However, Kaduna3 × Iyoyo had the highest fruit weight (1205 g) per plot, similar to Ogbojioroke and two others. The hybrid with the highest mean-weight per fruit (Yalo × Kaduna3 (BC2P1) was selected for a N-fertilizer trial where responses to N-fertilizer (urea) doses (0, 50, 100 and 150 kg ha^–1) and dosing options (single or half-split) were evaluated in the same environment. At 6 WAT, the number of nodes differed thus: 150/100 > 50 > 0 kg ha^–1, with half-split > single dosing. Flowering/fruiting time decreased with dose peaking at 100 kg ha^–1. Fruiting trailed in the order 150/100 > 50 > 0 kg ha^–1 in single and half-split dosing at 1st and 2nd harvests, respectively. Half-split dosing 150 and 100 kg ha^–1 produced similar and highest fruit weights (mean = 3110 g) per 3-m²-plot while 0 kg ha^–1 gave the lowest (mean = 433.50 g). Ogbojioroke's traits need to be exploited in eggplant improvement programmes. Half-split dosing 100 kg urea ha^–1 is suggested for promising varieties of eggplant grown on well-drained humid tropical soils.