Tampubolon K, Purba E, Basyuni M, Hanafiah DS. 2019. Glyphosate resistance of Eleusine indica populations from North Sumatra, Indonesia. Biodiversitas 20: 1910-1916. Controlling of Eleusine indica populations in oil palm plantations using a similar mode of action of herbicide may cause resistant weed. Overall E. indica populations from oil palm plantations in North Sumatra, Indonesia have never been reported to be glyphosate-resistant. This research was aimed to determine the survival percentage and to classify the resistance of E. indica to glyphosate from oil palm plantations in 11 districts in North Sumatra Province. The research was conducted in the Weed Research Center Field Laboratory, Faculty of Agriculture, Universitas Sumatera Utara from October 2016 to August 2017. This research was arranged in a Randomized Block Design with the glyphosate-treatment using a recommended dose of two l ha-1 and three replications. The ESU0 population was collected in the soccer field of Politeknik Negeri Medan (Medan city) was used as a check, and has never been exposed to the herbicide. Parameters were analyzed using one-way ANOVA, and the means were compared using DMRT at a probability level of 5%. The results showed that 276 (65.56%) of 421 populations were classified as glyphosate-resistant, 88 populations (20.90%) were classified as glyphosate-resistant developing, and 57 populations (13.54%) were classified as glyphosate-susceptible. The highest range of dry weight of glyphosate-resistant E. indica populations were found in 5 districts including South Labuhanbatu District followed by the Serdang Bedagai, Simalungun, Asahan, and North Labuhanbatu Districts. The observed resistance level and dry weight range in the present study indicated the failure in controlling E. indica due to continued use of glyphosate and the potency of E. indica distribution into other oil palm estates due to its high biomass production capability.

Eleusine indica populations on oil palm plantations in Deli Serdang Regency have not been reported to be resistant to glyphosate. This study was aimed to report distribution and resistance classification of E. indica population on oil palm plantations in Deli Serdang Regency. The research was conducted on Weed Research Center in Faculty of Agriculture, Universitas Sumatera Utara from October 2016 until August 2017. This research used Randomized Block Design with recommended dose at 720 g a.i.ha-1 of glyphosate and three replications. Population ESU0 (from Politeknik Negeri Medan Ball Field) as a comparison. Data on average survival, mortality, dry weight, resistance classification of E. indica were analyzeds using IBM SPSS Statistics 20 software. The results showed that there were 12 E. indica populations classified as glyphosate-resistant (56.52%), 7 glyphosate-resistant developing (30.43%), and 4 populations classified as glyphosate-susceptible (13.04%) with the recommended dose at 720 g a.i.ha-1 from oil palm plantations in Deli Serdang Regency.

Eleusine indica population from several estates in Padang Lawas and Tapanuli Selatan Regency, Sumatera Utara Indonesia has never been reported to be resistant to glyphosate herbicide. This study aims at distribution mapping and resistance classification of Eleusine indica glyphosate-resistant populations from several estates in Padang Lawas and Tapanuli Selatan Regency, Sumatera Utara. This research was conducted at Weed Research Center of the Faculty of Agriculture, Universitas Sumatera Utara from October 2016 to August 2017. This research used glyphosate at the recommended rate of 720 g ai ha-1 and three replications. Population ESU0 (from Politeknik Negeri Medan Ball Field) as a comparison. Data analysis using t-test at the level of 5% with IBM SPSS Statistics 20 software. The results showed 22 populations in Padang Lawas Regency have 8 populations classified as glyphosate-resistant (36.36%), 8 populations classified as developed-resistant (36.36%), and 6 populations classified as glyphosate-susceptible (27.27%). While from 6 populations in Tapanuli Selatan Regency have 5 populations classified as glyphosate-resistant (83.33%), 1 populations classified as developed-resistant (16.67%), and 0 populations classified as glyphosate-susceptible (0%). Keywords: glyphosate, goosegrass, oil palm plantation, resistance.

Improvement efforts to obtain high yield and adaptive varieties can be carried out through plant breeding programs. The success of irradiation in increasing population diversity is determined by plant radiosensitivity. Radiosensitivity aimed to determine a dose that caused plant death (lethal dose) or growth inhibition of 50% of the irradiated population (LD-50). The seeds of rice CV. Sidikalang was irradiated with gamma rays at doses of 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100 and 1200 Gy. The results showed that the value of Lethal Dose (LD-50) on the percentage of germination is 586.446 Gy and the gamma ray irradiation treatment gave different responses to plant height.

Agroecology affecting plant growth can be influenced by factors such as plant spacing and growing media. This study aims to determine the effect of plant spacing and chicken manure on the growth and production of green beans. Plants were planted at three spacing plants (20cm x 20cm, 20cm x 30cm, and 20cm x 40cm) while manure was applied at 3.75, 7.50 and 11.25 ton/ha and without manure as a comparison. The treatments were arranged in a randomized complete block design with three replicates. The result showed that the highest diameter of stem was resulted from the application of 11.25 ton/ha of manure combined with the planting space of 20cm x 40 cm. Similarly, the highest number of branch of stem we found at the plot where chicken manure of 11.25 ton/ha with planting space of 20cm x 30cm. The highest production (4,944.4 kg/ha) was resulted from 7.50 ton/ha manure with combined with planting space of 20cm x 40cm. There was an interaction between the treatment of manure and the planting space of soybean. The production of green bean was 24% higher in 7.50 ton/ha manure combined with 20cm x 40cm planting space compared to no manure (control).