Indonesian Journal of Agricultural Science
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RESPONSE OF SUB1 INTROGRESSION LINES OF RICE TO VARIOUS FLOODING CONDITIONS
Get PDFTwo types of floods can be happen in rice crops, i.e. flash floods and stagnant floods. Flash floods cause complete submergence for up to 2 weeks, while stagnant floods (SF) could partially submerge part of rice plant. To overcome yield loss due to the floods, introgression of SUB1 gene, known as a gene suppressing cell elongation and carbohydrate metabolism, to rice genotype can increase plant tolerance to complete submergence for 10 days or more. The study aimed to evaluate the response of 18 rice genotypes, including the recently developed sixth pair SUB1 near isogenic lines (NILs) of mega-rice varieties (Swarna, Sambha Mahsuri, IR64, TDK1, BR11, and CR1009), to various flooding conditions. The rice genotypes were planted at field ponds at Los Banos, Philippines, in the wet season (WS) of 2009. The treatments were 15 days submergence, SF, SF follows submergence and normal conditions. Each treatment was arranged in completely randomized block design with threereplications. The results showed that the SUB1 introgression rice lines had higher survival compared to the non-SUB1 and did not much elongate their shoots during submergence. Nevertheless, under SF the rice genotypes should elongates their shoots to allow restoring contact with the air. SF and SF follows submergence decreased the panicle number, grainnumber per panicle and panicle fertility. Consequently, the yield declined. It suggests that sensitive genotypes are mostly sourcelimited during grain filling. The SUB1 introgression lines had higher chlorophyll concentration and less depletion in soluble sugar and starch after submergence. Under SF, soluble sugar and starch contents between the SUB1 NILs and non-SUB1 lines were not significantly different. Introgression of the SUB1 into high-yielding varieties improved submergence tolerance without affecting yield potential. The study indicates that introgression of the SUB1 into taller type rice varieties should be done to compensate the effect of suppressed elongation
IDENTIFICATION OF WIDE COMPATIBILITY VARIETIES IN SOME TROPICAL JAPONICA RICE
Get PDFThe F1 hybrid sterility in indica/japonica crosses is the major barrier in developing hybrid rice varieties between these two diverse germplasm. The sterility problem in japonica/indica hybrids can be overcome by using wide compatibility genes. The objective of this study was to identify wide compatibility varieties (WCVs) in some tropical japonica rice. Twenty five tropical japonica varieties as male parents were crossed with indica (IR64) and japonica (Akitakomachi) testers as female parents. The crosses were planted following a randomized complete block design with three replications. Varieties having average spikelet fertility of more than 70% with both the indica and japonica testers were rated as WCVs. Result from this study showed that six tropical japonica varieties were classified as WCVs, i.e., Cabacu, Grogol, Kencana Bali, Klemas, Lampung Lawer, and Napa. Hybrid sterility is caused by partial sterility of male and female gametes. The WCVs from the present study can be used in hybrid rice breeding program to solve hybrid sterility in indica/japonica hybrids
LAND USE CHANGE AND RECOMMENDATION FOR SUSTAINABLE DEVELOPMENT OF PEATLAND FOR AGRICULTURE: Case Study at Kubu Raya and Pontianak Districts, West Kalimantan
Get PDFPeatland is an increasingly important land resource for livelihood, economic development, and terrestrial carbon storage. Kubu Raya and Pontianak Districts of West Kalimantan rely their future agricultural development on this environmentally fragile peatland because of the dominance (58% and 16% area, respectively) of this land in the two districts. A study aimed to evaluate land use changes on peatland and to develop strategies for sustainable peatland use and management for agriculture. Time series satellite imageries of land use and land cover, ground truthing, and statistical data of land use change were analyzed for generating the dynamics of land use changes in the period of 1986-2008. Field observation, peat sampling, and peat analyses of representative land use types were undertaken to assess peat characteristics and its agricultural suitability. The study showed that within 22 years (1986-2008), the area of peat forests in Kubu Raya and Pontianak Districts decreased as much as 13.6% from 391,902 ha to 328,078 ha. The current uses of the peatland in the two districts include oil palm plantation (8704 ha), smallholder rubber plantation (13,186 ha), annual crops (15,035 ha), mixed cropping of trees and annual crops (22,328 ha), and pineapple farming (11,744 ha). Our evaluation showed unconformity of the current uses of peatland with regulations and crops agronomic requirements such as peat thickness and maturity, rendering unsustainability. This study recommends that expansion of agriculture and plantation on peatland areas be limited over idle land within the agricultural production and conversion production forest areas. About 34,362 ha (9.7%) of uncultivated log-over forest and shrubs can potentially be developed for agriculture. Peat soils with the thickness of >3 m should be allocated for conservation or forest protection due to low inherent soil fertility and high potential greenhouse gas emissions if converted for agriculture
NITROUS OXIDE EMISSION AND NITROGEN UPTAKE AFFECTED BY SOIL AMENDMENT AND NEMATICIDE IN RAINFED RICE SOILS AT CENTRAL JAVA
Get PDFRice cultivation is one of the antropogenic sources of nitrous oxide (N2O) emission that is produced by microbiological nitrification-denitrification processes. Incorporating soil amendment in rainfed rice soil attempted to increase soil productivity, while nematicide application aimed to maintain root growth system. Incorporating soil amendment and nematicide application are predicted to suppress N2O production in lowland rice. The objective of this research was to study the interaction of soil organic amendment and nematicide on N2O emission and nitrogen uptake from rainfed lowland rice soils. A field experiment was conducted in rainfed lowland rice soils during 2010/2011 wet season (direct seeded rice) and 2011 dry season (transplanted rice). The 3 x 3 factorial trial was arranged in a randomized completely block design with three replications. The first factor was soil amendment consisted of without rice straw, fresh rice straw and composted rice straw. The second factor was nematicide application consisted of without nematicide, neemcake and carbofuran. Variables measured were N2O flux, rice grain yield and nitrogen uptake. Incorporation of fresh and composted rice straws reduced N2O flux about 49.2% and 59.9% in transplanted rice, and 32.9% and 28.2% in direct seeded rice, respectively. The neemcake application reduced N2O emission about 44-50%, while carbofuran application decreased N2O emission by 23-35%. Neemcake has a good potential as nitrification inhibitor of N2O emission, so the neem trees have a prospect to be cultivated intensively. The reduction of N2O emission was effective in direct seeded rice system with the application of neemcake and fresh rice straw, however, in transplanted rice system it was effective with neemcake and composted rice straw applications
METHANE EMISSION FROM PADDY FIELDS AS INFLUENCED BY DIFFERENT WATER REGIMES IN CENTRAL JAVA
Get PDFThe concentration of methane (CH4) in the atmosphere is increasing at 1% per annum and rice fields are one of the sources that contribute to about 10-15% of the atmospheric CH4. One of the options to reduce greenhouse gas emission from rice fields is probably through water management. A field study was conducted to investigate the effects of water management practices on CH4 emission from rice field plots on a silty sand Aeric Tropaquept soil at Research Station for Agricultural Environment Preservation, Jakenan, Central Java, Indonesia, during the dry season of March to June 2002. Four water regimes tested were: (1) 5 cm continuous flooding (CF), (2) 0-1 cm continuous flooding (ST), (3) intermittent irrigation (IR) where plots received continuously 5 cm of flooding with two times of draining at 15-20 and 25-30 days after transplanting (DAT), and (4) pulse irrigation (PI) where plots were watered until 5 cm level and left to dry by itself until the water table reached 30 cm beneath soil surface then watered again. The total CH4 emissions of the four water treatments were 254, 185, 136 and 96 kg CH4 ha-1 for CF, ST, IR and PI, respectively. Methane emission increased during the early growing season, which coincided with the low redox potential of -100 to -150 mV in all treatments. Dry matter weight of straw and filled grain among the water treatments did not show significant differences. Likewise, total grain yield at 14% moisture content was not significantly different among treatments. However, this result should be carefully interpreted because the rice plants in all water treatments were infested by stem borer, which reduced the total grain yield of IR64 between 11% and 16%. This study suggests that intermittent and pulse irrigation practices will be important not only for water use efficiency, but also for CH4 emission reduction
THE FINANCIAL FEASIBILITY OF RICE DRYERS: A Case Study in Subang District, West Java
Get PDFDrying is a critical activity in rice postharvest handling. Any delay in drying will result in quality and quantity losses. Farmers and traders prefer to sell wet grain rather than dried grain of unhulled rice due to less attractive incentive for them to do drying. The study was conducted in Subang District, West Java, during March-June 2011 using survey method to analyze the financial feasibility of rice dryers. The respondents interviewed were 15 rice millers who have either sun-drying floor or mechanical dryer, or both. The main collected data were the investment cost, operational cost, maintenance cost, and the revenue of the dryers. The data were analyzed by using shortterm and long-term financial analyses to assess the profitability and feasibility of some drying technologies. The results showed that there were at least three drying technologies in the study area, namely sun-drying floor, flatbed dryer using gas fuel (gas dryer), and flatbed dryer using rice husk fuel (husk dryer). Under the mean capacity, the short-run MBCR of technological change from sun dryer to gas dryer was 1.29, while from sun dryer to husk dryer was 1.45. The long-run analysis showed that the IRRs were 44.44% for sun dryer, 233.47% for gas dryer, and 260.49% for husk dryer. These results showed that among the three drying technologies, husk dryer is the most profitable, most feasible, and most prospective to be adopted. Therefore, this type of dryer should be intensively promoted to the farmers’ group associations, rice traders, and rice millers. The government support in terms of rice dryers for farmers’ group associations should be focused on husk dryer
LACK OF EFFECT OF PRETREATMENT ON THE VIABILITY OF MACADAMIA (Macadamia integrifolia) SEED
Get PDFOne problem in developing macadamia in Indonesia is the limited availability of good quality seed. Viability of the seed is easily lost and erratic, and the seed has long dormancy periods. The objective of the study was to find a method for enhancing germination percentage of macadamia seed. The study evaluated different pretreatments of macadamia seeds before planting. The pretreatments were period of fermentation, i.e., 0, 1, 2, 3, 4, 5, 6, and 7 daysone day each soakingdrying-soakingone day each drying-soaking-dryingand alternate drying-soaking until the seeds were cracked. The treatments were arranged in completely randomized design. Results showed that no treatment significantly affected percentage of seed germination, index of speed of germination, number of leaves, and dehydrogenase enzyme activity, but treatments significantly affected seedling height and electric conductivity of seed leakage solution. Seed germination percentage ranged from 66.67 to 86.67
UNTAGGED MUTATION IN RICE GAL4/VP16 TRANSCRIPTIONAL ACTIVATOR FACILITATED-ENHANCER TRAP LINES
Get PDFAn enhancer trap system is an insertional mutagenesis based upon gene expression, instead of gene knock-out, so its insertion in genome is expected not linked to any dramatic changes in plant phenotypes. Gene knock-out, leading to lossof- function (LoF) mutation, is a dominant approach for rice functional genomic studies. The objective of this study was to find out whether Transcriptional Activator-Facilitated Enhancer Trap (TAFET) T-DNA insertion inducing mutant phenotypes in rice TAFET population. Materials used in this experiment were T1 generation of 270 rice TAFET lines. Eight plants of each were grown in the greenhouse and observed for any mutant phenotypes. Phenotypic, histochemical, Southernblot analyses were carried out to define a mutant of pSKC66.1- 8e. Result showed that about 10% of the 270 lines produced chlorophyll-deficient leaves, ranged from yellowish green (viridis), white stripe green zebra-like stripe) to completely white (albino). Albino plants died after two weeks, whilst white stripe or viridis mutants became normal in the next generation(T2). Another mutant was pSKC66.1-8e line which had floral dramatic phenotype change with various spikelet shapes and number of organs, and had a single twisted culm. The flower of mutant also had gus gene expression. Plants with wild type did not express gus gene and had six or more straight culms. Molecular, histochemical and phenotypic analyses of this particular line for three generations indicated that mutant phenotype was not due to the T-DNA insertion. Since there was approved that Tos17 is activated during tissue culture and induced mutant phenotype, this line might relate to Tos17 insertion, but it needs further investigation to gain such conclusion
ANALYSIS OF GENETIC PARAMETERS FOR BEAN PHYSICAL QUALITY CHARACTERS AND CLUSTERIZATIONS OF ELEVEN GENOTYPES OF ROBUSTA COFFEE (Coffea canephora)
No full textThe genetic parameters of coffee related to their bean physical quality characters are important for breeder to improve the bean quality. Eleven genotypes of robusta coffee were identified and their genetic relationship to the bean physical quality were characterized. The research was conducted at coffee plantation of the Association of Indonesian Coffee Exporters in West Lampung, altitude of 800 m above sea level, Latosol type of soil, and A type of climate, starting from 2010 to 2012. The objectives of this study were to estimate the genotypic coefficient of variation, heritability and genetic advance of the bean physical quality characters, and clusterization analysis of eleven genotypes of robusta coffee. A randomized complete block design with eleven treatments of coffee genotypes and three replications was used in this study. The results showed that the estimated values of genotypic coefficient of variation, heritability and genetic advance for small-size normal bean characters of robusta coffee were very high, so the genetic improvement for these characters has a high probability of success by direct selection. Clusterization of the genotypes resulted three clusters with their respective characteristics. The study implies that future breeding program especially for hybridization should be conducted between genotypes arising from different clusters to obtain the possible high heterosis effects
MULTIFUNCTIONAL MUTANTS OF Azospirillum sp. WITH ENHANCED CAPABILITY OF SOLUBILIZING PHOSPHORUS, FIXING NITROGEN AND PRODUCING INDOLE ACETIC ACID
Get PDFAzospirillum sp. have long been known as biofertilizer for plant growth because of its capability to produce phytohormones and fix nitrogen from the atmosphere. Multifunctional Azospirillum strain Aj Bandung 6.4.1.2 isolated in 2009 from cauliflower (Brassica oleracea) rhizosphere in Lembang, Bandung, West Java, was capable of fixing nitrogen, solubilizing tricalcium-phosphate, and producing phytohormone indole acetic acid (IAA). The study aimed to modify the multifunctions of Azos-pirillum sp. for better capability of fixing N2, solubilizing P, and producing IAA using ethyl methanesulfonate and 1-methyl-3-nitro-1-nitrosoguanidine (EMS) mutagen. The study was conducted at Indonesian Center for Agricultural Biotechnology and Genetic Resources Research and Development (ICABIOGRAD) in 2010. The results showed that this strain was genetically mutagenized using EMS for better performance in solubilizing P, fixing N2 (nitrogenase activity), and producing phytohormone (IAA). The optimum concentration and the length of incubation time for the process have been determined. Nine selected mutants with increasing capability to solubilize P (determined by clear-zone formation on Pikovskaya’s medium) have been characterized for nitrogenase activities and IAA production compared to wild type Aj Bandung 6.4.1.2. The effect of mutagenesis on IAA produc-tion and nitrogenase activities varied among the mutans. Two mutants, AzM 3.7.1.16 and AzM 1.7.2.12, showed superiority in the production of IAA, while two mutants, AzM 1.5.1.14 and AzM 3.7.1.15, were superior in nitrogenase activities. The EMS mutagenesis of Azospirillum sp. showed enhanced dissolving capa-bility of unsoluble phosphate (tricalciumphosphate) and increased IAA production and nitrogenase activity.