Mechanical conditioning of tomato seedlings improves transplant quality without deleterious effects on field performance

Excessive stem elongation reduces plant survival in the field and hinders m echanical transplanting. Mechanical conditioning is an effective method for reducing stem elongation during transplant production. This investigation examined the consequences of mechanical conditioning, using brushing and im pedance, on subsequent field performance of tomatoes (Lycopersicon esculent um Mill.). Mechanically conditioned transplants of processing tomatoes resu med growth after transplant shock as quickly as did untreated plants, and s ubsequent canopy development was also equal. in 4 years of field trials, yi eld was not reduced by mechanical conditioning, Transplants for fresh-marke t tomatoes may be more sensitive to injury than those for processing tomato es because they flower sooner after the conditioning treatments. Neverthele ss, neither earliness nor defects in the fruits of the first cluster were a ffected by mechanical conditioning. Early and total yields were equal in bo th gears that fresh-market crops were tested. Thus, there were no adverse e ffects on field performance of either processing or fresh-market tomatoes a s a result of reducing stem elongation by mechanical conditioning before tr ansplanting. Improved wind tolerance was tested both in a wind tunnel and i n the field. In wind-tunnel tests, brushed and impeded plants resisted stem bending at wind speeds 4 to 12 km.h(-1) higher than did untreated plants. A 70 km.h(-1) wind after transplanting killed 12% of untreated plants but o nly 2% of treated plants. Mechanical conditioning with brushing and impedan ce produced transplants with desirable qualities without adverse effects on field performance.