การประเมินผลกระทบของการใช้แก๊สเอทธิลีนต่อต้นยางพาราอายุน้อยที่เปิดกรีดแล้วเปรียบเทียบกับต้นยางพาราแก่

Abstract

According to a marked increase of latex price in 2011, rubber smallholders tried to increase the tapping productivity by ethylene gas stimulation. Therefore, it needed to be tested the impact on rubber trees. Then, an experiment was established at Thepa Research Station, Songkhla province. Both young tapping rubber trees (9-years-old) and old tapping rubber trees (21-year old) were tested. The experiment was design as one tree plot design with 6 treatments the old tapping rubber trees (OT): T1: S/3U 2d/3 6d/7, T2: S/8U d3 6d/7, T3: S/8U d3 6d/7 ETG (ethylene gas) 99% RIMMFLOW-60-36/y (9d), T4: S/8U d3 6d/7 ETG 60% LET-40-48/y (6d), T5: S/8U d3 6d/7 ETG 99% Double Tex -60-36/y (9d), T6: S/8U d3 6d/7 ET 5% Pa 1 (2) 12/y (m). There were 6 treatment in the young tapping rubber trees (YT): T1: S/3 2d3 6d/7, T2: S/6 d3 6d/7, T3: S/6 d3 6d/7 ETG 99% RIMMFLOW-60-36/y (9d), T4: S/6 d3 6d/7 ETG 60% LET-40 48/y (6d), T5: S/6 d3 6d/7 ETG 99% Double Tex -60-36/y (9d), and T6: : S/6 d3 6d/7 ET 2.5% Pa 1 (2) 12/y (m). The experiment was arranged in 20 replicates. The experimental period was during 2011-2013. It was prominent that cup lump yield of OT in T3 (S/8U d3 6d/7 ETG 99% RIMMFLOW-60-36/y (9d)) (8416 g/t) was the highest followed by T5 (S/8U d3 6d/7 ETG 99% Double Tex -60-36/y (9d)) (8147.2 g/t), they were significant difference from T4 (S/8U d3 6d/7 ETG 60% LET-40-48/y (6d)) (7014.6 g/t). The yield of T6 (S/8U d3 6d/7 ET 5% Pa 1 (2) 12/y (m)) (4203.5g/t), T1 (S/3U 2d/3 6d/7) (4101.6 g/t) and T2 (S/8U d3 6d/7) (3549.5 g/t) were significantly lower than the remaining treatment. However, in the YT, T5 (S/6 d3 6d/7 ETG 99% Double Tex -60-36/y (9d)) (4959.5g/t) and T4 (S/6 d3 6d/7 ETG 60% LET-40-48/y (6d)) (4948.4 g/t) were significant higher than the other treatment. T1 (S/3 2d3 6d/7) (4305 g/t) and T3 (S/6 d3 6d/7 ETG 99% RIMMFLOW-60-36/y (9d)) (4139.5 g/t) were not significant different. The lowest yield was in T2 (S/6 d3 6d/7) (2205.8 g/t). In OT, dry rubber content (DRC) was the highest in T2 (S/8U d3 6d/7) (50%) followed by T1 (S/3U 2d/3 6d/7) (46.7%), which T3 (S/8U d3 6d/7 ETG 99% RIMMFLOW-60-36/y (9d)) (33.9%) was significant lowest. DRC of (S/8U d3 6d/7 ETG 60% LET-40-48/y (6d)), T5 (S/8U d3 6d/7 ETG 99% Double Tex -60-36/y (9d)) and T6 (S/8U d3 6d/7 ET 5% Pa 1 (2) 12/y (m)) were 45.3, 44.3 and 45.3% respectively. In YT, DRC of (S/3 2d3 6d/7) (47.4%), T2 (S/6 d3 6d/7) (45.9%) and และ T3 (S/6 d3 6d/7 ETG 99% RIMMFLOW-60-36/y (9d)) (45.9%) were higher than the other treatments, whereas DRC of T4 (S/6 d3 6d/7 ETG 60% LET-40-48/y (6d)) (43.4%) was the lowest. Besides, it was evident that bark consumption of T1 (S/3 2d3 6d/7 และ S/3U 2d/3 6d/7) was the highest and significant difference from the other treatments in both YT and OT. There was no significant difference in bark consumption among the treatments of T2 (S/6 d3 6d/7, S/8U d3 6d/7), T3 (S/6 d3 6d/7 ETG 99% RIMMFLOW-60-36/y (9d), S/8U d3 6d/7 ETG 99% RIMMFLOW-60-36/y (9d)), T4 (S/6 d3 6d/7 ETG 60% LET-40-48/y (6d), S/8U d3 6d/7 ETG 60% LET-40-48/y (6d)), T5 (S/6 d3 6d/7 ETG 99% Double Tex -60-36/y (9d), S/8U d3 6d/7 ETG 99% Double Tex -60-36/y (9d)) and T6 (S/6 d3 6d/7 ET 2.5% Pa 1 (2) 12/y (m), S/8U d3 6d/7 ET 5% Pa 1 (2) 12/y (m)) The results of latex diagnosis in both YT and OT showed that T2 (S/6 d3 6d/7, S/8U d3 6d/7) provided the highest sucrose, whereas T5 (S/6 d3 6d/7 ETG 99% Double Tex -60-36/y (9d), S/8U d3 6d/7 ETG 99% Double Tex -60-36/y (9d)) exhibited the lowest sucrose. The treatments of ETG application trended to reduce sucrose. Whereas the application of ETG increased inorganic phosphorus in both YT and OT. However, there was no significant difference of thiol among the treatments.