Increase of the Production Potential of Strobilanthes cusia (Nees) for Local Textile Dyeing in the Upper North of Thailand

Abstract

Strobilanthes cusia (Nees) (Kuntze) is a shrub that grows in the natural forests of the upper North. It has been widely and popularly used as raw material for dyeing the local textile products and is now in short supply. Phrae Agricultural Research and Development Center has been collecting, conducting cloning comparison and developing S. cusia production technology during 2012-2020. The objectives were to study suitable varieties and production technology in the upper northern region and transferred the information to farmers. Results showed that S. cusia could be classified into 2 groups; the large leaf (Strobilanthes cusia (Nees) Kuntze) and the small leaf (Strobilanthes sp.). The two groups had no different growth. But the large leaf group gave higher fresh yields and indigo substance than the small leaf group. The suitable plant spacing was 50x60 cm from which fresh yield of 1,266 kg/rai was obtained. Seventy percent shading increased fresh yield to 3,315 kg/rai. The harvesting index was 9 months after planting which gave fresh yield of 4,592 kg/rai. Optimal time to harvest was between 7.00-11.00 am which gave 421-463 kg/rai
of indigo plate. When testing the production technology of 10 farmers in Phrae province. It was found that using DOA technology farmers could harvest 4 times/year with fresh yield of 3,844 kg/rai, 769 kg of indigo paste with a unit cost of 7,063 baht, an income of 38,436 baht, and a return profit of 31,373 baht. Using the farmers’ technology the plant could be harvested 2 times, with fresh yield of 1,773 kg/ rai, 355 kg of fresh produce with production cost of 4,909 baht, an income of 17,728 baht, and a net profit of 12,819 baht. These
activities obviously increased farmers and communities income and helped maintain the wisdom into the future.