Performance and genetic assessment of rubber tree clones in Southern Thailand

Thailand is the world leader in the production of latex extracted from the rubber tree (Hevea brasiliensis). However, the most cultivated clone RRIM 600, is highly susceptible to diseases, and there is economic incentive to develop new rubber tree clones. Four rubber tree clones (T2, SK1, NK1 and SK3) that have high latex yield potential from plantations in Southern Thailand were selected for this study. Yield performance, latex biochemical parameters and anatomical characteristics of bark were monitored for two years, using RRIM 600 clones in the same fields as paired controls. The average yields of the clones SK1, NK1 and SK3 were 129.3, 74.2 and 53.9 g per tree per tapping, respectively, surpassing the paired RRIM 600 controls (94.3, 49.9 and 43.9 g per tree per tapping in matching order). There was a difference in girth increment of SK1, SK3 and T2 clones when compared with RRIM 600, whereas the clones SK1 and T2 had higher renewed bark thickness than the paired RRIM 600. The anatomical measurements showed that the diameter of the latex vessels and density of latex vessels mm−2 were the highest in clone NK1, which also had the best latex biochemical parameters. This indicates NK1 is superior, and supports its use in Hevea breeding programs to improve latex yield. Our genetic characterization and assessment of the four clones selected used Random Amplified Polymorphic DNA (RAPD) and Simple Sequence Repeats (SSR). Seventeen recommended rubber clones were included as references. The clones SK3 and SK1 were closely related to RRIM 600 with similarity coefficients of 0.891 and 0.809, while NK1 and T2 were closely related to RRIT 250 (0.836) and RRIC 110 (0.864), respectively

Genetic diversity, genetic variability, and path analysis for yield and its components in indigenous upland rice (Oryza sativa L. var. glutinosa)

Genetic diversity, genetic variability, and relationships of yield and its components are very important data for plant breeders that affect the design of a breeding program. Twenty-two upland rice genotypes were evaluated. The genotypes indicated significant variations in nine traits. High phenotypic and genetic coefficients of variation were observed for yield per plant, number of panicles per plant, and number of spikelets per panicle. High broad-sense heritability and genetic adaptations were found for yield per plant. Positive significant correlations were recorded between flag leaf length, number of panicles per plant, and number of spikelets per panicle. The highest direct effects on yield were attributed to the number of spikelets per panicle and the number of panicles per plant. Cluster analysis grouped the 22 genotypes into groups I, II, and III, and the outgroups consisting of nine, five, six, and two genotypes. These results may facilitate upland rice breeding programs to improve yield

Intellectual property right in genetic resources

Plant genetic resources for food and agriculture are necessary in food production and biodiversity conservation. These are the most important natural resources, in addition to air, water and soil. Unfortunately, during the evolution large number of plant genetic resources has been lost. The biggest negative impact on loss of plant genetic resources had been made by humans through the modernization of agriculture and the creation of varieties of high genetic uniformity. FAO and its operation through international mechanisms, such as the adoption of the Convention on Biological Diversity, the first legal act which regulates all levels of biodiversity: ecosystems, species and genetic resources, biotechnology, including the Cartagena Protocol on Biosafety (regulates the transfer of genetic material across the border), contributed to the conservation of plant genetic resources for food and agriculture. In addition to the Convention on Biological Diversity, FAO has been defined by the International Treaty on Plant Genetic Resources for Food and Agriculture in more specific and detailed way, the preservation of genetic resources. The objectives of the International Treaty on Plant Genetic Resources for Food and Agriculture are the conservation and sustainable use of all plant genetic resources for food and agriculture and the fair and equitable sharing of the benefits arising out of their use. There are four basic pillars which form the substance of the Contract, Sustainable use of plant genetic resources, Farmers' Rights, the Multilateral System and the Global Information System. Two organizations, the International Biodiversity and the International Union for the Protection of New Varieties of Plants trying to solve the issues of protection of the population and old varieties as intellectual property

Characterization of the phenylalanine ammonia lyase gene from the rubber tree (Hevea brasiliensis Müll. Arg.) and differential response during Rigidoporus microporus infection

Phenylalanine ammonia lyase (PAL) is a specific branch point enzyme of primary and secondary metabolism. It plays a key role in plant development and defense mechanisms. Phenylalanine ammonia lyase from Hevea brasiliensis (HbPAL) presented a complete open reading frame (ORF) of 2,145 bp with 721 encoded amino acids. The sequence alignment indicated that the amino acid sequence of HbPAL shared a high identity with PAL genes found in other plants. Phylogenetic tree analysis indicated that HbPAL was more closely related to PALs in Manihot esculenta and Jatropha curcas than to those from other plants. Transcription pattern analysis indicated that HbPAL was constitutively expressed in all tissues examined, most highly in young leaves. The HbPAL gene was evaluated by quantitative real-time PCR (qRT-PCR) after infection with Rigidoporus microporus at 0, 12, 24, 48, 72 and 96 hours post inoculation. The expression patterns of the PAL gene differed among the three rubber clones used in the study. The transcription level of the white root rot disease tolerant clone, PB5/51 increased sharply during the latter stages of infection, while it was relatively subdued in the white root rot disease susceptible clones, RRIM600 and BPM24. These results suggest that the HbPAL gene may play a role in the molecular defense response of H. brasiliensis to pathogen attack and could be used as a selection criterion for disease tolerance

Detection methods and survey of GM crops in Thailand

Prince of Songkla Universit

Characterization and genetic relatedness among 37 yardlong bean and cowpea accessions based on morphological characters and RAPD analysis

Twenty four yardlong bean and 13 cowpea accessions were planted in the field to characterize their morphology and genetic relatedness. A randomized complete block design (RCBD) with two replicationswas used. Growth habit, days to flowering, pod color, pod length, number of pods/plant, yield/plant and consumption quality were recorded. The results showed that pod length, number of pods/plant and podyield/plant among 37 accessions were highly significant differerence. Mean pod yield and pod length of 24 yardlong bean accessions were 212.1 g/plant and 48.7 cm, respectively, while mean pod yield and pod lengthof 13 cowpea accessions were 117.4 g/plant and 21.3 cm, respectively. Twenty two yardlong bean accessions exhibited indeterminate growth habit while 10 of 13 cowpea had determinate growth habit and the restsexhibited semi-determinate growth. Genetic variation and relationships among accessions were investigated based on RAPD technique. Total DNA was extracted from young leaf samples of all accessions using CTAB buffer. One hundred and twenty decamer oligonucleotide primers were screened and 5 primers (OPC-06,OPR-12, OPZ-03, OPZ-08, OPZ-13) were chosen for further evaluation. A dendrogram of genetic similarity was constructed based on 23 polymorphic bands obtained from 5 primers using UPGMA in SPSS program,which revealed separate groups between yardlong bean and cowpea. The similarity coefficient among yardlong bean and cowpea accessions ranged from 0.515 to 1.000 and 0.548 to 1.000, respectively

Impact of Nitrogen Application Rates on Upland Rice Performance, Planted under Varying Sowing Times

Application of suitable nitrogen (N) fertilizer application rate (NR) with respect to sowing time (ST) could help to maximize the performance and productivity of upland rice in Southern Thailand. The 2-year experiments were conducted in the sheds to evaluate the agronomic responses of the upland rice genotype, Dawk Pa–yawm, under various combinations of NR and ST between 2018–2019 and 2019–2020 aimed at obtaining sufficient research evidence for the improved design of long-term field trials in Southern Thailand. As with the initial research, four NR were applied as N0 with no applied N, 1.6 g N pot−1, 3.2 g N pot−1 and 4.8 g N pot−1, and experiments were grown under three ST including early (ST1), medium (ST2) and late sowing (ST3). Results from the experiments indicate that the application of 4.8 g N pot−1 resulted in maximum grain yield under all ST in both years. However, a maximum increase in grain yield was observed under ST2 by 54–101% in 2018–2019 and by 276–339% in 2019–2020. Maximum grain N uptake of 0.57 and 0.82 g pot−1 was also observed at NR 4.8 g N pot−1 under ST2 in both years, respectively. Application of NR 4.8 g N pot−1 resulted in the highest N agronomic efficiency (NAE), nitrogen use efficiency (NUE) and water use efficiency (WUE). However, the performance of yield and yield attributes, N uptake, N use efficiencies and WUE were declined in late sowing (ST3). Significant positive association among yield, yield attributes, N uptake and WUE indicated that an increase in NR up to 4.8 g N pot−1 improved the performance of Dawk Pa–yawm. The results suggest that the application of 4.8 g N pot−1 (90 kg N ha−1) for upland rice being grown during September (ST2) would enhance N use efficiencies, WUE and ultimately improve the yield of upland rice. However, field investigations for current study should be considered prior to general recommendations. Moreover, based on the findings of this study, the importance of variable climatic conditions in the field, and the variability in genotypic response to utilize available N and soil moisture, authors suggest considering more levels of NR and intervals for ST with a greater number of upland rice genotypes to observe variations in field experiments for the precise optimization of NR according to ST