Influence of Harvesting Date on Yield and Seed Quality of Indigo (Indigofera tinctoria L.)

Abstract

         Indigo (Indigofera tinctoria L.) is a member of the family Leguminosae. Indigo has traditionally been used for fabric dyeing of local handicrafts because it imparts beautiful shades and highly stable colors. One problem with indigo seed planting and cultivation is that seed maturation is not simultaneous, and thus many seeds have to be planted to ensure an economic yield. Moreover, the fact that there is a lot of variation in the planted seeds’ maturity times often produces a longer wait until harvest and a longer harvest time, factors which tend to negatively affect the quality and yield of the seeds. This research was therefore designed to determine the optimum harvesting date for the yield and seed quality of Indigo (Indigofera tinctoria L.). The research was conducted at the Plant Science Field, Sakon Nakhon Rajabhat University, during the rainy season of 2016. The experiment was of random complete block design (RCBD) with 4 replications and involved 7 harvesting dates: 140, 150, 160, 170, 180, 190 and 200 days after planting (DAP). The results showed that harvesting dates (DAP) had significant effects on pod fresh weight, pod dry weight, seed dry weight per plant, seed moisture and seed germination. The highest seed germination was found at 150 DAP (53.31%), but these plants harvested at 150 DAP had low seed dry weights per plant and lower total seed germinations per plant (1,270 seeds/plant) affected. The highest total seed germinations found were for 180 DAP (2,673 seeds/plant), followed by 200 and then 190 DAP. Therefore, it was concluded that the optimum harvesting dates were 180 DAP and higher, which were periods after planting that gave the highest yield and seed quality of Indigo.