Integrated Harvesting Techniques for African Egg Plant (Solanum macrocarpon L., cv. Igbagba)

Aim: This study elucidated the influence of harvesting height and frequency on concurrent seed and
shoots production of the African Eggplant, Solanum macrocarpon L., cv. Igbagba/Igbo. The overall
aim was to use the outcome to make recommendations that would enable African resource poor
farmers secure the much needed increase in income for improved livelihoods.
Experimental Design: The experiment was a three (harvesting heights of 0.04 m, 0.08 m and 0.12
m) by five (harvesting frequencies of 1x per 1,2,3,4 and 5 weeks) factorial treatment arrangements
fitted into randomized complete block with 4 replications. There was a control treatment which was
harvested at ground level six weeks after planting for vegetative yield estimation and a check which
was left for seeding without cutting. Net plot size was 5 m x 5 m (25 m2).
Place and Duration of Study: The study was carried out between April to November 2004 on the
National Horticultural Research Institute (NIHORT) Ibadan, Nigeria commercial vegetable production
fields.
Methodology: Cumulative shoot fresh weight over the cutting period gave the shoot yield per plant.
S. macrocarpon fruits were harvested, processed for seed and the seed weighed at 12% moisture
content. Seed and shoot yield values were based on current NIHORT [National Horticultural Research
Institute, Nigeria] prices of N450.00 per kilogram seed and N10.00 per kilogram shoot (US$1 = N80 at
time of data collection, N is Nigerian Currency). Harvest index was calculated as seed weight/shoot
weight which indicates changes in the pattern of dry matter partitioning into seed and shoot. Cutting
Use Efficiency (CUE) was defined as the relative agronomic efficiency of using cutting over the
control. Data were subjected to analyses of variance by the procedure of the Statistical Analysis
System (SAS, 2005) using mean of 10 plants per treatment plot. Marginal revenue (MR) equals field
price per kilogram multiplied by average yield (kg/ha) where field price is the market value of one
kilogram of the crop. Marginal cost (MC) included those costs that are affected by the alternative
treatment being considered (costs such as planting, land purchase, land preparation and transport
that do not differ across treatments will be incurred regardless of which treatments is used). Data from
both seasons (long cropping season and short cropping season) for each treatment were combined
because there were no seasonal significant differences. Means were compared using Duncan's
Multiple Range Test (DMRT) at 5% significance.
Results: Shows that harvesting at 0.08 m above ground level was optimal and significantly highest for
leaf, stem, shoot, seed and total yields except at 0.12 m above ground level for seed production. The
result of financial profitability analysis shows that harvesting 0.08 m above ground level and fortnightly
was most profitable for leaf, shoot and total yields compared to all the treatment combinations.
Harvesting 0.12 m above ground level and monthly, however, was most profitable for seed production
when compared to all treatments combinations.
Conclusion: The study concluded noting that integrated harvesting techniques for shoot (leaf + stem)
and seed production proved economically viable and optimize resource use efficiency better than
growing S. macrocarpon sole either for shoot or seed.