Potato microtubers are the miniature of conventional seed tubers grown in the field. Producing potato microtuber in vitro at high temperature by applying many kinds of tuber promoting substances is similar to producing potato in the field at low elevation by applying the same tuber promoting substances. The objective of this research was to evaluate the performance of seven tuber promoters in inducing potato microtubers at high temperatures. Micro cuttings (6 weeks old) were grown at the liquid media of MS for stolon induction. Six weeks afterward, the media were moved to microtuber inducing media supplemented with tuber promoters ((FD, FD+10 COU, FD+20 COU, FD+30 COU, FD+40 COU, FD+50 COU, and IPB). The media were incubated in the dark at 20 + 2 o C and 29 + 2 o C. The results showed that, in general, high temperature inhibited crop growth and tuber formation. Individually, tuber promoter formula significantly affected microtuber emergence, in which IPB showed the slowest treatment in producing microtubers, the smallest number of tuber produced, and the smallest size of tubers. The interaction between temperature and tuber promoters were significantly affected the tuber formation, in which the fastest tuber formation (7,0 days ) was found in FD + 40 COU and the highest percentage of plant producing tubers was found in FD + 30 COU. Moreover, the highest number of microtuber and the heaviest weight of microtuber were found in FD (no Coumarin). It was safely concluded that all tuber promoters were best performed at low temperature. Should anyone wish to make those tuber promoters work better at high temperature, it is recommended to increase the concentration of Coumarin added to the formula of tuber promoting substances.Keywords: high temperature, in vitro, potato microtubers, tuber promoter INTISARI Umbi mikro kentang merupakan miniatur umbi kentang yang digunakan sebagai benih untuk penanaman di lahan. Produksi umbi mikro kentang pada suhu tinggi dengan zat pemacu pembentukan umbi (tuber promoter) dijadikan sebagai simulasi produksi kentang di dataran rendah dengan menggunakan formula tuber promoter. Tujuan penelitian ini adalah mengkaji pembentukan umbi mikro kentang pada suhu tinggi dengan berbagai formula tuber promoter. Stek mikro kentang berusia 6 minggu tanpa akar dan pucuk ditanam pada media cair untuk menginduksi pembentukan stolon. Pada usia 6 minggu stek mikro dipindahkan ke media induksi umbi mikro yang telah diberi

Extending the planting area to a less-fertile soil, such as Ultisols, become inevitable choice to increase the national chili pepper production in Indonesia as this types of soil is the largest part of dry land of Indonesia, about 29.7% or around 51 million ha.  However, efforts to increase its productivity by providing sufficient fertilizers application is most frequently inefficient because in the conventional fertilizer applications, broadcasted fertilizer on the soil bed, are not readily available for the plant as their solubility is limited under the plastic mulch and still in the form of granular until the end of planting season.  Fertigation, therefore, maybe the answer for this problem.  The objective of this study was to determine the best NPK fertigation method on four chili pepper hybrids.  The experiment was conducted in a randomized complete block design with three replication, and the treatments were arranged in a split plot design.  As the main plots were NPK fertigation intensity, i.e. 100%, 75%, 50%, 25% and 0% fertigation with the remnant fertilizers were circularly broadcasted surrounding the plant.  As the subplots were chili pepper hybrids, i.e. ‘Maxima’, H39, H14, and ‘UNIB CHR17’.  The results showed that there was no interaction effect of fertigation intensity indicated that all hybrid genotypes showed similar pattern of responses.  The H39 hybrid had better vegetative growth compared to other hybrids in term of plant height, dichotomous height, stem diameter, number of branches, plant fresh-weight.  Whereas the hybrid cultivar ‘Maxima’ showed the highest yield followed by H14 and cultivar ‘UNIB CHR17’.  The 100% fertigation was the best method of NPK fertilizer application for chili pepper in Ultisols.keywowrd: fertigation, chili pepper, fertilizer application, acidic soil

Increasing soybean production can be done by growing the crops in marginal soil, such as saline soil. Therefore, saline-tolerant genotypes are important to support the cultivation. The objective of the experiment was to evaluate the performance of 18 soybean varieties grown under salinity stress. The experiment was done from May to July 2021 at the greenhouse of the Department of Agronomy, Faculty of Agriculture, Bengkulu University, about 10 m above sea level. Soybean seedlings were grown in 10 cm diameter plastic pots fertilized with AB-mix solutions supplemented with 0 or 6 dSm-1 NaCl for 15 days. The growth and stress-tolerant index of the seedlings were measured. The results showed that soybean variety had different growth as responses to salinity. Moreover, salinity stress imposed at 6 dSm-1 NaCl significantly reduced crops growth and promoted leaf senescence. We found that 18 soybeans varieties were classified as salinity tolerant at 6 dSm-1. Keywords: saline, soybean varieties, tolerant

A common problem related to the production of potatoes in Indonesia is the use of poor quality seed sources and declining seeds. Plant tissue culture is one of the best methods used for the provision of quality seeds. This study aims to establish the best combination of BAP concentration and the concentration of paclobutrazol in spurring the growth of cuttings and initiation of potato tubers in vitro.This research was conducted in November 2017 until June 2018 at Agronomy Laboratory of Biotechnology Division and Plant Culture Network of Agriculture Faculty of Bengkulu University. The  research  design  used  was  Completely  Randomized  Design  (CRD)  which  consist  of  18 combination of BAP treatment and Paclobutrazol was repeated 6 times. The concentration of BAP used was 0 mg / l, 5 mg / l, 10 mg / l and the concentration of Paclobutrazol 0 mg / l; 2.5 mg / l; 5 mg / l; 7.5 mg / l; 10 mg / l; 12.5 mg / l. The data of the research were analyzed by F test of 5% level and if there were different between treatments followed by Duncan's Multiple Range Test (DMRT) test of5% level. The results showed that the combination of BAP and  Paclobutrazol concentration had significant effect on all observed variables. Treatment of 5 mg / l BAP and 7.5 mg / l Paclobutrazol is the best medium in inducing potato micro tube as indicated by the fastest tuber formation time, highest percentage of productive crops, largest number of tubers per bottle, number of tubers per productive plant, tuber diameter the largest and highest wet weight of tuber per bottle. Keywords : in vitro, BAP, paclobutrazol, Potato

Growing potato crops at low elevation in the tropical region may face many problems related to high temperature, such as an increase in endogen GA3 levels, causing the inhibition of tuber formation. Suppressing GA3 biosynthesis, by applying a mixture of plant growth regulators (PGRs), is of important. The objectives of this experiment were to study the best PGR mixtures, PGR application time, and their interaction in promoting tuber formation at low altitude of tropical areas in Indonesia. The experiment used a completely randomized design arranged in factorial (2 factors, 3 replications). The first factor was a mix of plant growth regulator solution (M), consisting of 4 levels, which were: M0 = No PGR; M1 = 10 ppm 2,4-D + 100 ppm Daminozide, M2 = M1 +10 ppm BAP, M3 = M1 + 25 ppm COU, and M4 = M1+ 500 ppm PBZ. The second factor was application time of the solutions (T), consisting of 3 levels, which were: T1 = 3, 4, 5, 6 weeks after emergence (WAE), T2 = 3, 4, 5 WAE, and T3 = 3, 4 WAE. The results showed that all of the PGR mixtures promoted tuber formation with 10 ppm 2,4-D + 100 ppm Daminozide + 500 ppm Paclobutrazol was found as the best PGR mixture. Moreover, the best time to spray the mixture was 3,4,5,6 WAE. Finally, the best interaction between PGR and application time was10 ppm 2,4-D + 100 ppm Daminozide + 10 ppm BAP applied at 3,4,5 WAE.