Assessment of the drought response of genetically diverse eggplant genotypes

Water is the leading environmental factor that affects crop productivity. Unexpected and prolonged drought adversely limit yield in the vegetable crops such as eggplant. Such an occurrence could affect the income of stakeholders in the vegetable industry. Improved varieties with drought tolerance are needed to reduce the impact brought by sudden water limitation in production areas. This study was conducted to identify genotypes with diverse drought responses that can be used as parental lines in a drought breeding program. One hundred eggplant genotypes from the collection of the National Plant Genetic Resources Laboratory in UPLB were screened in batches for drought tolerance. The eggplants originated from the Philippines, Taiwan, USSR, Africa, Iran, India, Laos, Fiji, China and Turkey. Sixty-seven genotypes were Solanum melongena, while the rest were S. linociera, S. nigrum, S. aculeatissima, S. sisymbriifolium, S. parkinsonii, S. stramonifolium, S. ferox, and S. nodiflorum. Wild accessions and commercial varieties (Dumaguete Long Purple and Mistisa), were also included in the screening. Six weeks after transplanting, the eggplant seedlings were seeded to 16-liter plastic pails, and drought was imposed by withholding water. The response to drought varied among the 100 entries. Root dry weights increased in 25% of the entries screened, while the root dry weights decreased in the rest of the entries evaluated. There was a general reduction in the total dry matter yield in 87% of the entries. However, some genotypes (13%) even increased their total dry matter yield under drought, which is a desirable trait. Sixty-seven of the entries increased the root biomass, indicating that these entries were able to adapt to drought stress. Twenty eggplant genotypes that were identified to exhibit drought tolerance were entered in a verification trial. Over-all the results indicate that there was diverse response to drought, and this diversity can be utilized in selecting parental lines.