NITROGEN INFLUENCE AND FRUIT HARVESTING METHOD ON THE PERFORMANCE AND SEED QUALITY OF OKRA (Abelmoschus esculentus L. Moench) IN MINNA, NIGERIA

Abstract

The study was carried out both on the field at the Teaching and Research Farm and in the laboratory of the Department of Crop Production, Federal University of Technology, Minna, in the Southern Guinea Savanna Ecological Zone of Nigeria during the 2019 and 2020 cropping seasons. The treatments consisted of two okra varieties (NHAe47-4 and LD 88-1), five rates of nitrogen fertilizer (0, 30, 60, 90 and 120 kg N ha 1).The experimental design was a 2 x 5 factorial giving 10 treatments combinations fitted into a Randomized Complete Block Design (RCBD) replicated three times.Each plot measures 2×5.25 m (10.5m2 ) comprising of eight ridges with 3 replications. Parameters measured includesdays to first flower bud sight and opening, days to 50% flowering, plant height, number of leaves, stem girth and leaf area at days to flower bud sight and opening and days to 50% flowering, number of productive branches, flower abortion incidence, number of fresh fruits, fresh fruit diameter and fresh fruit length, fresh fruit weight/plot, dry fruit diameter, dry fruit length, number, weight of seeds per fruit and 100-seed weight. Seed qualityexperiment (I) consisted of three factors,two okra varieties (NHAe47-4 and LD 88-1), five nitrogen rates (0, 30, 60, 90, and 120 kg ha-1 ) and six fruit positions on the mother-plant (1, 2, 3, 4, 5 and 6th) which was a 2 x 5 x 6 factorial fitted into a Completely Randomized Design (CRD) with four replicates.Seed quality experiment (II) consisted of three factors of two okra varieties (NHAe47-4 and LD 88-1),five nitrogen rates (0, 30, 60, 90, and 120 kg N ha-1 ) and seven fruit harvesting stages (14, 21, 28, 35, 42, 49 and 56 days after anthesis) which was 2 x 5 x 7 factorial fitted into a Completely Randomized Design (CRD) and replicated four times.The seed quality tests were evaluated using fruit diameter, fruit length, number of seeds, seed weight, seed moisture content, germination test, germination rate index, electro-conductivity test after harvest. The data collected were subjected to analysis of variance (ANOVA) using SAS Statistical package 9.2 (2016) at 5% level of probability; means were separated using Least Significant Difference (LSD) Test.The results revealed thatapplication of 90-120 N kg/hais optimum for okra due to enhanced growth and yields in the study area. However, flowering was delayed when N was applied. Plants to which no fertilizer was applied performed poorly in respect of all parameters studied. Seeds of LD88-1 also stored better than seeds of NHAe47-4. Seeds harvested at 42 (DAA) maintainedsuperior longevity, irrespective of the cultivar used.With the result of this study, we could advise okra farmers in the zone toplant NHAe47-4 with the application of 90- 120 N kg/ha for its bigger fruits. Fruits harvested at 42 days after anthesis produced seeds which germinated and stored better than other harvesting stages. The fruits formed at the lower position 1-3 on the mother-plants at 42 DAA should be harvested for high quality seed and storage. The results also showed that significantly enhanced growth, fruit and seed yield was recorded at 90-120 N kg/ha in this agro-ecological zone