Effect of planting density on yield components of nightshade

Abstract

Nightshade species (Solanum L. section Solanum, e.g., S. scabrum, S. tarderomotum, S. villosum, S. americanum and S. grossidentatum) are widely cultivated in East and West Africa due to their potential nutritional and economic benefits. Constraints associated with the production of nightshade species include little information on their production practices. This study was conducted at AVRDC-The World Vegetable Center in Arusha, Tanzania to evaluate the yield response of nightshade to plant density. Eleven accessions collected from different countries in Africa representing a wide genetic diversity conserved at AVRDC were evaluated over two seasons in years 2004 and 2005. The experiment was conducted in the field in plots laid-out in 4×11 factorial randomized complete block design, with 3 replications. Four planting densities at 20×50 cm (10 plants/m2), 40×50 cm (5 plants/m2), 60×50 cm (3.3 plants/m2) and 80×50 cm (2.5 plants/m2) were used as treatments. Data on leaf, fruit and seed yields were collected. Results revealed differences in the response of various yield components to plant density as well as differences between lines. Leaf, fruit and seed yields per plant increased significantly (P≤0.05) with increasing spacing while fruit and seed yield per unit area (t/ha) were not affected by spacing treatments (P≤0.05). Leaf yield per unit area decreased significantly with a decrease in spacing from 27.4 to 11.76 and 9.03 t/ha, respectively (for Seasons 1 and 2). The highest leaf, fruit and seed yields per plant were observed at a spacing of 80×50 cm. In general, Solanum scabrum accessions gave the best overall yields compared with S. tarderomotum, S. villosum, S. americanum and S. grossidentatum species, with accession BG16 recording the highest yields and accession MW13-2 recording the lowest. A density of 10 plants/m2 is recommended for leaf production of nightshade while a density of 3.3 plants/m2 is recommended for fruit and seed production.