Comparison between phytotron- and glasshouse-propagated fig (Ficus carica L.) trees grown under similar solution culture on subsequent fruiting, plant growth, and fruits quality

Abstract

Cuttings from one-year-old wood of fig cv. Masui-Dauphine were made on Dec. 1, and raised for 45 days in a glass house or phytotron under different light intensities. The rooted cuttings were planted on Jan. 15, in a non-circulating closed solution culture, using a capillary absorption system together with a irrigation tube. The effects of nursery treatments on subsequent fruiting, plant growth, and fruit quality were investigated in the current year. Light treatment of 8.5 klx under a 14-hr photoperiod in a phytotron increased total chlorophyll content and color value of the leaf at planting time. The number of fruits below the 5th node increased in trees when the color value of 3rd leaf from the base was above 25 at planting time. But, there was no difference in leaf color value and fruiting between the light treatment of 17 and 8.5 klx. The supplementary lighting of 0.2 klx after sunset to keep 14-hr of sunlight in the glass house had no effect on leaf color value; it approximated that of the control. Harvest started on May 27; by July 10,85% of the fruit was harvested. In trees raised in the phytotron, vegetative and fruit growth was promoted, contrary to those raised in the glass house. The Brix value was slightly lower in fruits from the phytotron-grown trees in early June. During the rainy season from the middle to the end of June, fruit growth did not decrease and the Brix decreased significantly because of the reduced photosynthetic rate, a high transpiration rate, and the large uptake of nutrient solution, irrespective of the treatment. Trees raised in the phytotron had higher photosynthetic rates than did trees raised in the glass house in July, but the fruits from the former had lower Brix values than had fruits from the latter.