Thermal neutron beam from thermal column was selected for a Boron Neutron Capture Therapy
(BNCT) system utilizing the Malaysian TRIGA MARK II reactor. Determination of shielding
materials for fast and epithermal neutron was conducted. The materials selected were polyethylene,
paraffin and water. For gamma-ray shielding, lead was used. The objective of this paper is to present
the simulation and verification of an optimal design of BNCT collimation at a beam. line viewing the
thermal column. A collimator was made from polyethylene pipe with 8 cm of diameter filled with
paraffin.
Heavy ion beam, which has emerged as a new mutagen in the mutation breeding of crops and ornamental plants, is expected to result in the induction of novel mutations. This study investigates the morphological and biochemical responses of Oryza sativa toward different doses of carbon ion beam irradiation.
In the present study, 63 polymorphic microsatellite markers related to rice blast resistance genes were fluorescently labelled at the 5'-end with either 6-FAM or HEX using the G5 dye set and incorporated into a multiplex SSR-PCR for the detection of fragments using an automated system. For rice F3 families obtained from crosses between Pongsu Seribu 2 (Malaysian blast resistant cultivar) and Mahsuri (a susceptible rice cultivar), the genotypes for 13 designated multiplex SSR panels were determined. The genotyping assays were performed using a capillary-based ABIPRISM 3100 genetic analyser. The sizes of the SSRs alleles observed in the range from 79 to 324 bp. The observed marker segregation data were analysed using the Chi(2) test. A genetic linkage map covering ten chromosomes and comprising 63 polymorphic SSR markers was constructed, and the distorted loci were localised to linkage groups. The results indicated that distorted loci are presented on eight chromosomes.
Late embryogenesis abundant (LEA) proteins are primarily found in plants stem, roots, and other organs and play significant roles in tolerance to several abiotic stresses. Plants synthesize a discrete set of LEA proteins in response to drought stress. In this study, the expression patterns of LEA genes were investigated in two advanced mutant rice genotypes subjected to the drought stress condition and different physiological traits including photosynthetic rate, leaf chlorophyll content, and photosystem II (PSII) photochemical efficiency (Fv/Fm) which were analyzed to confirm their drought tolerance. Five LEA genes (OsLEA1, OsLEA2, OsLEA3, OsLEA4, and OsLEA5) were used in the evaluation of rice genotypes and were significantly upregulated by more than 4-fold for MR219-4 and MR219-9. The upregulated genes by these two varieties showed high similarity with the drought-tolerant check variety, Aeron1. This indicates that these advanced mutant genotypes have better tolerance to drought stress. The changes in the expression level of LEA genes among the selected rice genotypes under drought stress were further confirmed. Hence, LEA genes could be served as a potential tool for drought tolerance determination in rice. MR219-4 and MR219-9 were found to be promising in breeding for drought tolerance as they offer better physiological adaptation to drought stress.
The genomics and genetic information of Malaysian rice (Oryza sativa L.) and their mutant lines are very limited. Therefore, the genome resequencing of two drought and submergence tolerant mutant rice lines, NMR152 and NMR151 and their parental line, MR219 was performed using Illumina Hi Seq 4000 platform with 20x sequencing coverage to facilitate the identification of causal mutations and the discovery of candidate variants of single nucleotide polymorphisms (SNPs) from their genome. The identification of SNPs would be useful in developing functional SNP markers related to drought and submergences resistance traits. Genome sequence data (FASTQ format) of the mutants and their parental line have been deposited into the National Center for Biotechnology Information (NCBI) database under sequence read archive (SRA) data with accessions SRR20824202 (NMR152), SRR20995190 (NMR151) and SRR21043964 (MR219), respectively.
Induced mutation for the creation of desirable traits through chronic gamma irradiation provides an opportunity for the selection and development of new chili varieties. This study was conducted to assess the effects of different doses of chronic gamma irradiation on morpho-physiological traits in chili. Ten plants from each variety were exposed to different doses of chronic gamma irradiation for 277.02 h at three weeks after germination under gamma greenhouse facilities, with accumulative dose; 185.61Gy, 83.11Gy, 47.096Gy, 30.474Gy, 19.4Gy, 13.9Gy, 11.1Gy, 8.31Gy, 5.54Gy) and 2.77Gy respectively. Highly significant differences were observed among doses (Rings) of chronic gamma irradiation expressed in mean values for all investigated traits. Relatively moderate doses of chronic gamma irradiation represented by doses 47.096 Gy (Ring 4) and 19.40 Gy (Ring 6) resulted in significant stimulation for most of the studied characters. The highest heritability was recorded in days to flowering at 99.88 while the lowest was observed in fruit dry weight at 34.66 %. High genetic advance were recorded for most of the quantitative traits studied. In addition, a highly significant positive correlation was observed between total fruit per plant, total number of fruit per plant, plant height, fruit fresh weight, number of secondary branches, chlorophyll a, fruit dry weight, total chlorophyll content, stem diameter, fruit length and fruit girth. With increasing chronic gamma dose, mutagenic efficiency and efficacy generally increased. Induced variety of desirable features will considerably increase the chilli's amelioration through mutation breeding, leading to the development of improved varieties. The results of this research offer valuable information for the use of chronic gamma radiation in the mutations breeding of Capsicum annuum L., which will be advantageous for future breeding programs.
In Malaysia, rice mutant varieties that are genetically altered to confer resistance against blast disease have been substantially developed through mutational breeding program. However, due to the limited accessible information on the mutant lines, mutant gene variants corresponding to the disease resistance and other useful agronomic traits are yet to be exploited. Here, we conducted whole genome re-sequencing of blast resistance with kernel elongation traits in mutant line, Mahsuri Mutant (87,639,446 bp raw reads), and its parental line, Mahsuri (85,156,783 bp raw reads) using Illumina Novaseq 6000 sequencing platform with 30x sequencing coverage. The generated genome sequences are aimed to facilitate the discovery of causal mutation and single nucleotide polymorphisms (SNPs) related to the intended traits. The identified SNPs can be further employed to develop allele-specific SNP molecular markers to locate the mutant gene regions. The NGS data obtained (FASTQ format) of the parental and mutant lines have been deposited in the National Center for Biotechnology Information (NCBI) database under sequence read archive (SRA) xwith accession numbers SRR24388814 (Mahsuri) and SRR22952097 (Mahsuri Mutant) respectively.