Shading effects of intercropping roselle (Hibiscus sabdariffa) genotypes on plant development, assimilate partitioning and leaf nutrient content

Mebelo Mataa ,B Makungu ,Inonge N Siziya

doi:10.3329/ijarit.v8i1.38223

Abstract

An experiment was conducted to determine the effects of shade on plant development, macronutrient and secondary metabolites in roselle (Hibiscus sabdariffa). Three roselle accessions (ZM 5729, ZM 5738 and ZM ZM5748) acquired from the Zambia National Plant Genetic Resource Centre were used and shade was imposed by intercropping roselle with maize (Zea mays). A Split plot design with shade as main plot and genotype as split- plot was used. Nutritional and development parameters were monitored. At 14 weeks shaded plants had about a three-fold decrease in branches numbers compared to unshaded ones. Plant height was higher in unshaded treatments (120 cm) compared to shaded (83 cm). Plant height of ZM 5738 was significantly higher than the other two accessions. Shading reduced dry matter accumulation by almost 75 % across genotypes with about 20 g per plant in shaded treatments and 73 g in unshaded treatments. Nutrient reductions were highest in fat (60.6 %), fibre (48.4 %), protein (37.8 %), and lowest in ash (27.3 %). In terms of strength of partitioning the pattern was: branches ˃ leaves ˃ roots ˃ squares ˃ flowers. The carbohydrate content increased with shading (10.6 %). Vitamin C content was higher in unshaded treatments in comparison with shaded conditions. ZM 5738 had the highest content followed by ZM 5748 and ZM 5729 had the least content. Oxalates which are an anti- nutrition factor increased with shade. The findings showed that there is significant variation among genotypes and in future selections can be made to choose the most productive genotypes.Int. J. Agril. Res. Innov. & Tech. 8 (1): 7-13, June, 2018

Highlights

The consumption of fresh fruits and vegetables in Zambia is low among the high income households (Hichaambwa et al, 2009)
In addition to having high protein, carbohydrates and fibre, work done in other countries has shown the vegetable to be rich in secondary metabolites (Obouayeba et al, 2015)
Differences in plant height emerged at 5 weeks after planting (Fig. 1A)

Summary

Introduction

The consumption of fresh fruits and vegetables in Zambia is low among the high income households (Hichaambwa et al, 2009). This low and declining consumption of fruits and vegetables is not unique to Zambia but a worldwide phenomenon (Casagrande et al, 2007; Pomerleau et al, 2004). Indigenous plants provide a cheaper and affordable source of nutrients and can play a critical role especially among the low income households (Hichaambwa et al, 2009). In Zambia one of the potentially important sources of nutrients and secondary metabolites is the indigenous vegetable, roselle (Hibiscus sabdariffa).

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