Testing of Ethylene Stimulation to Enhance Latex Yield of Hevea Brasiliensis Clone RRIM 600 in Southern Thailand

Recently, latex price has continuously increased, This motivates rubber smallholders in southern Thailand to increase latex productivity. Then, ethylene stimulation has been introduced in tapping systems. Therefore, it needs to be tested before recommendation to the smallholder. An experiment was established at Thepa Research Station, Songkhla province. Rubber clone RRIM 600 (20 year-old) was used in the experiment. The experiment was designed as one-tree-plot design with 20 replicates. There was 6 treatments: 1) 1/3S­ 2d/3 (C), 2) 1/8S­ 1d/3, 3)1/8S­ 1d/3 + RRIMFLOW (RF), 4)1/8S­ 1d/3 + LET (LET), 5) 1/8S­ 1d/3 + Double Tex (DT) and 6) 1/8S­ 1d/3 + Ethyphon 5% (E). The experimental period was during June 2010 to February 2011. It was found that the RF treatment provided the highest rubber productivity (137.7 g/tree/tapping and 5.9 kg/tree/year), and it was significantly different from the remaining treatments. According to latex diagnosis, sucrose in the RF treatment trended to decrease, but inorganic phosphate and thiol trended to increase

Monitoring seasonal fine root dynamics of Hevea brasiliensis clone RRIM 600 in Southern Thailand using minirhizotron technique

Rubber tree (Hevea brasiliensis) plantations in various environments are affected by climate variability, and the fine root dynamics of rubber trees significantly respond to environmental factors. Therefore, rubber clone RRIM 600 was used to investigate the fine root dynamics in southern Thailand using minirhizotron imaging at 0-60 cm soil depths from February 2014 to January 2015. Dynamics of fine root production and mortality were greater in the rainy season than in the dry season. The fine root distribution peaked around 20-30 cm and decreased over 40-60 cm soil depths. The maximal leaf area index (April 2014) was found 2 months after leaf flushing, while the fine roots showed a slight increase after leaf development for 1 month (May 2014). Both rainfall and soil moisture had significant (p<0.01) positive correlations with fine roots of which there were more in the rainy season than in the dry season

Assessment of fruit density and leaf number: fruit to optimize crop load of mangosteen

To optimize crop load of mangosteen, fruit density and leaf number: fruit were assessed using a framework of quadrat cube (0.5 x 0.5 x 0.5 m) in 2 consecutive years (2004-2005). Twenty-four 14-year-old uniform trees, field grown at Songkhla province, were selected to arrange 4 levels of crop loads: 1) Extremely low crop load (T1) = 264±5 fruit pt-1, 2) Low crop load (T2) = 826±36 fruit pt-1, 3) Medium crop load (T3 ) = 1190±27 fruit pt-1 and 4) High crop load (T4) = 1719±36 fruit pt-1. By placing the quadrat cube on the tree canopy, leaves quadrat-1 and fruits quadrat-1 were counted. Relationship between fruits quadrat-1 and fruit number pt-1 was found, and leaf number: fruit was also related to fruit yield pt-1. These results indicate that the assessment of fruit density and leaf number: fruit is of benefit for crop load management. Thus, 9 fruits quadrat-1 and 18 leaves: fruit are recommended to optimize crop load of mangosteen