Eggplant (Solanum melongena L.) Plant Growth and Fruit Yield as Affected by Drip Irrigation Rate

The objective was to assess the effects of irrigation rate on plant growth and fruit yield in eggplant.  The study was conducted in Tifton, GA.  Eggplant (‘Santana’) plants were grown on raised beds (1.8 m centers) covered with white plastic film mulch. There was a single drip tape along the center of the bed. The design was a randomized complete block with five treatments and four replications.  Treatments consistent of irrigation rates based on crop evapotranspiration (33%, 67%, 100%, 133%, and 167% ETc).  Plant growth, chlorophyll index (SPAD) and volumetric soil water content (SWC) were monitored over the season.  As expected, SWC increased with increasing irrigation rates. Chlorophyll index decreased with irrigation rate, possibly as a result of a dilution effect on leaf N.  Additionally, increased irrigation rates possibly resulted in increased nitrate leaching.  Stem diameter, leaf dry weight and vegetative top dry weight increased with increasing irrigation rate. Fruit number and fruit yields (marketable and total) were lowest at 33% ETc and there were little yield differences among irrigation rates higher than 33% ETc.  Results suggest that eggplant may tolerate mild water stress, since plants irrigated at 67% ETc produced fruit yields similar to those of plants irrigated at 100% ETc or higher rates.  Thus, there is potential to reduce irrigation rates without negatively impacting fruit yields.