Effects of Interplanting on Fruit Yield and Dry Matter Production in Greenhouse-grown Tomato by Integrating Two Different Crop Periods

We investigated the effects of interplanting on fruit yield in greenhouse-grown tomato by integrating the first (short) and second (long) crop periods in the cooler northern area of Japan. The marketable fruit yield was similar regardless of interplanting in the first crop period, whereas it increased with earlier planting dates in the second and total crop periods. Therefore, planting immediately after the harvest of the first fruit trusses of the first crop period was effective in achieving a continuous harvest and substantial yield improvement upon conclusion of the harvest of six trusses; moreover, there were no incidences of stem lowering in the first crop period. The plant dry weight was also similar regardless of interplanting in the first crop period. However, the total dry weight and fruit dry weight increased with early interplanting in the second and total crop periods. The marketable fruit yield and total dry matter production of the whole crop period increased when cultivation started in March compared with that in April. The dry matter allocation to the fruit was similar among the treatments in all crop periods. The total fresh and dry fruit yields were significantly correlated with the cumulative light interception over the total crop period. Therefore, fruit yield was the highest when cultivation started in March with interplanting in the early-summer resulting in the highest light interception and dry matter production.