Effects of shade on agronomic traits of doubled haploid lines of eggplant (Solanum melongena L.) obtained from anther culture

Low-light stress can inhibit plant growth and production. The selection of superior genotypes that are adaptive and tolerant to low light intensity needs to be performed. This study evaluated the agronomic responses of ten doubled haploid lines of eggplant and three varieties to various shade levels (0%, 25%, and 50%). This study used a split-plot design with three replicates. The results indicate that 25% shade is the optimal selection environment for shade tolerance. Genotypes grown under 25% shade exhibited varying responses, with two genotypes classified as shade-loving, seven as tolerant, three as moderately tolerant, and one as shade-sensitive. Shade levels of up to 50% significantly reduced yield, with production dropping to 58%–81% of the unshaded conditions. In general, growth characteristics such as plant height, leaf width, and leaf area were better under shaded conditions, whereas the yield was better under unshaded conditions. AM 23, AM 14, and AM 10 showed better tolerance responses and maintained better yields than the other lines under 25% shade. This study provides important insights into the development of shade-tolerant eggplant varieties. These findings can be used as a basis for recommendations for eggplant planting in shaded areas such as agroforestry systems.