Culm Diameter Research Articles

Genome Wide Association Analysis for Uniform Coleoptiles Emergence and Early Seedling Growth in Rice

Early seedling vigour (ESV) is a complex trait in rice. Detection of QTLs/genes controlling these traits can help us in enhancing the yield potential in rice varieties. Association mapping is a technique based on the principle of linkage disequilibrium that is used to find genes or quantitative trait loci (QTL) underlying the complex traits. In this study of haplotype breeding 281 rice genotypes were taken. ANOVA analysis showed P- value for traits and genotypes was found significant. Similarly, P-value for interaction between the traits and genotypes was also found to be highly significant (1.8663*10-208). Further, mean germination data positively correlated with mean shoot length, mean leaf number, mean culm diameter, mean shoot dry weight, and mean shoot area of 21st day among the 281 genotypes. Among the 281 number of genotypes, 111 genotypes are found to be in PCA1 and 170 genotypes are found to be in PCA2 based on the phenotypic analysis. PCA1 component constituted 29.93% and PCA2 constituted the 13.68% of total variation in the analysis. Besides, whole genome phylogenetic analysis showed three major groups of which Group 1 consists of 215 genotypes, group 2 consists of 38 genotypes and group 3 consists of 28 genotypes respectively. Especially, both the subgroups II and III comprised of the unique genotypes from the indica and aus subpopulations of rice. In this analysis, 16 significant associations (LOD Score >7) for different traits were identified using the three different models (MLM, farmCPU, and blink) for GWAS studies Especially, one major QTL was identified for the mean coleoptiles’ emergence for 10 DAS on 11th chromosome (18983591) which explained 49% of the phenotypic variance. Additionally, another major QTL contributing to the shoot length variation of 29.75% was identified in the Chr02 (32954393) for shoot length trait on 28 DAS. A candidate gene namely Os02g0778400 UMP/CMP kinase A/adenylate kinase (LOC_Os02g53790) was located in the significant SNP region of the GWAS analysis. Further characterization of this gene would assist in elucidation of the mechanism regulating the early seedling length in rice under direct seeded rice.

Paclobutrazol Enhanced Stem Lodging Resistance of Direct-Seeded Rice by Affecting Basal Internode Development.

The objectives of this study were to explore the mechanism of stem mechanical strength in direct-seeded rice (DSR) as affected by paclobutrazol, especially its related endogenous hormone and cell wall component changes in culm tissue and response to the application of paclobutrazol. Field experiments were conducted in Changchun County, Jilin Province, China, by using two japonica rice varieties, Jiyujing and Jijing305, with soaking seeds in paclobutrazol at concentrations of (0 mg L-1, S0; 50 mg L-1; S1; 100 mg L-1; S2; 150 mg L-1, S3; 200 mg L-1, S4) in 2021 and 2022. The results suggest that the application of paclobutrazol increased the grain yield and reduced the lodging rate of DSR. Compared with the S0 treatments, soaking the seeds in paclobutrazol treatments rapidly shortened the length of the basal internode by decreasing the endogenous indole acetic acid (IAA) and gibberellin A3 (GA3) contents in culm tissue. The larger breaking strength (M) was attributed to a higher section modulus (SM) and bending stress (BS). The higher mechanical tissue thickness in culm tissue under paclobutrazol treatments, which was raised by higher endogenous zeatin and zeatin riboside (Z+ZR) content in culm tissue, increased the culm diameter, culm wall thickness, and section modulus (SM) of the internode. Compared with the S0 treatments, soaking the seeds in paclobutrazol treatments increased the cellulose content, lignin content, activities of lignin-related enzymes, and expression of key genes in lignin biosynthesis, as well as resulted in a higher bending stress (BS) to enhance the culm breaking strength (M).

Effect of elevation and aspect on carbon stock of bamboo stands (Bambusa nutans subsp. Cupulata) outside the forest area in Eastern Nepal

Bamboo has emerged as a promising option for climate change mitigation due to its rapid growth, versatility, and renewability. However, in Nepal, there exists a substantial knowledge gap on carbon (C) stock and the influence of aspect and elevation on C stock of bamboo species, particularly in areas outside forests where bamboo is dominant. Therefore, this research was conducted to quantify C stock and aspect-elevation influence on the C stock of Bambusa nutans subsp. cupulata outside the forest area. For this study, three elevation zones (0–400 m, 400–800 m, 800–1200 m) and two aspects (East and West) were considered. A total of 30 square plots having a 100 m2 area were established utilizing purposive sampling due to the scattered distribution of bamboo. Non-destructive methods were applied to measure bamboo culm diameters, while composite soil samples were systematically collected from 30 cm depth using soil augers and core samplers. Clump density (400 ha⁻¹), culm density (42,480 ha⁻¹) and culm diameter (6.82 ± 0.41 cm) were highest at middle elevations (p < 0.05), with no significant difference due to aspect (p > 0.05). The total mean C stock potential of B. nutans was 148.73 ± 3.43 Mg ha⁻¹. Our results indicated a significant difference in C stock among elevation zones, with middle elevation zones (161.77 ± 6.74 Mg ha-1) exhibiting notably higher C stock compared to both lower (150.26 ± 2.69 Mg ha-1) and higher (134.17 ± 4.26 Mg ha-1) elevation zones. Furthermore, East aspect was found to have significantly (p < 0.05) higher soil organic C stock (18.52 ± 1.32 Mg ha-1) compared to West aspect (11.4 ± 1.01 Mg ha-1). Further research is needed to explore other complex environmental interactions with C stock potential for better climate change strategies. Incorporating bamboo C into Nepal's REDD+ initiative can be crucial for optimizing opportunities to earn C credits.

Effects of harvesting techniques and intensities on productivity of Oxytenanthera abyssinica in Pawe district, North-western Ethiopia

Bamboos are naturally fast-growing species in tropical and non-tropical regions, with some species growing more than 1 m per day. Oxytenanthera abyssinica is an important bamboo species that could help meet current and future needs worldwide. This study was designed to assess the effects of harvesting techniques and intensities on sustainable utilization of O. abyssinica. Clumps that had a similar number culms were used to conduct the experiment. A factorial experiment with two harvesting techniques (X-shape and Horse-shoe shape) and five levels of harvesting intensities (25, 50, 75, 100 and 0 % harvesting of mature culms) was conducted for five successive years in the dry season. Sprouted and dead shoots, recruited culms, and mean culm diameter at breast height were recorded. Data were analysed using two-way-ANOVA. Culm/shoot sprouting had significantly different values with harvesting techniques; the X-shape harvesting technique produced a higher number culms than horse-shoe harvesting technique. Interaction effects between harvesting techniques and harvesting intensities on shoot sprouting, culm recruitment and shoot abortion were not observed. Both harvesting techniques and intensities had a significant effect on mean culm diameter; i.e., 25 % and 75 % of the mature culms harvested under the X-shape and horse-shoe harvesting techniques, respectively, produced thicker bamboo culms than the unharvested clump (control). Culm recruitment decreased in the second year, and then increased in the third year, subsequently showed a decreasing trend for all treatments. This may have been related to repeated culm harvesting. The population structure has also varied with harvesting technique and intensity. To utilize this species sustainably, the species may need a specific cutting cycle. This study suggests the need for further study through incorporating cutting cycles with different levels of harvesting intensity to develop a sustainable management method.

Experimental Study on the Dowel-Bearing Strength of Bambusa blumeana Bamboo Used for Sustainable Housing Construction

This study addresses the critical issue of dowel-bearing strength in Bambusa blumeana, a key sustainable construction material crucial for climate change mitigation. Given the lack of bamboo connection standards, this research focuses on determining the dowel-bearing strength of Bambusa blumeana, emphasizing factors such as dowel diameter, node placements, and the physical properties of bamboo. A predictive equation is derived, enhancing the practicality of bamboo in structural design. The results underscore a notable correlation between dowel diameter and characteristic strength, with implications for engineering practices. Node placements significantly affect dowel-bearing capacity, while bamboo’s physical attributes, including thickness, culm diameter, and moisture content, exhibit modest correlations with strength. The derived equation aims to assist in structural design, mitigating splitting and bearing failures in bamboo structures. This research establishes a foundation for optimizing the use of Bambusa blumeana in sustainable construction, advancing the understanding of its dowel-bearing strength for improved sustainability and resilience in the construction industry. Future research suggestions include exploring bamboo–mortar composites, additional node placements, and employing more comprehensive empirical equations and curve-fitting techniques. The study advocates for further investigations with more diverse and larger bamboo samples to bolster robustness. Additionally, delving into bamboo ductility may offer valuable insights.

Adaptation and growth performance of different bamboo species in Dryland areas of Northern Ethiopia

Bamboos are among the large perennial grasses that are renowned for their remarkable vigor and quick development. However, the amount of bamboo available in natural settings is decreasing as a result of shifting agriculture, overexploitation, and forest fires. Furthermore, there is little genetic diversity in our country because just two species are found in a small number of agroecological zones. This makes it difficult to guarantee a steady supply of bamboo, despite its benefits to the environment and economy. Thus, the goal of this study was to evaluate the adaptability and growth performance of four bamboo species: Oxytenanthera abyssinica (A.Rich.) Munro, Phyllostachys edulis (Carrière) J Houz, Bambusa vulgaris Schrad. ex J.C. Wendl, and B-ambusa bambos (L) Voss'. The study was carried out at the Mekelle Agricultural Research Center compound for four years, from 2020 to 2023. Three replications of a strict RCBD design were used in the experiment. There were four plants each plot, for a total of 48 plants, and there was a three-meter gap between each plant and plot. A range of growth indicators, including new shoot emergence, culm diameter, internode length, culm height, and survival rate, were measured at three-month intervals in order to monitor changes among the species. B. bambos, B. vulgaris, and O. abyssinica showed no problems with survival or adaptation in the research locations, with the exception of small growth variances. Significant changes (p≤ 0.05) in the treatment parameters were shown by the statistical analysis. O. abyssinica displayed a noticeably greater quantity of freshly emerging bamboo shoots in comparison to other bamboo species. Conversely, P. edulis showed the lowest growth metrics in terms of internode length, culm height, culm diameter, and survival rate. P. edulis, B. vulgaris, O. abyssinica, and B. bambos had survival rates of 16.67 percent, 66.67 percent, 75 percent, and 91.67 percent, respectively. It is noteworthy that seasonal differences have a substantial impact on the height of culms and the growth of newly emergent shoots. B. vulgaris, B. bambos, and O. abyssinica all showed good growth and survival rates. As a result, it is advised to highlight and promote these species in related agroecological areas, as this can benefit multiple stakeholders’ livelihoods and economies.

Discrepancy of flowering time between genetically close sublineages of Aegilops umbellulata Zhuk.

Aegilops umbellulata Zhuk., a wild diploid wheat-related species, has been used as a genetic resource for several important agronomic traits. However, its genetic variations have not been comprehensively studied. We sequenced RNA from 114 accessions of Ae. umbellulata to evaluate DNA polymorphisms and phenotypic variations. Bayesian clustering and phylogenetic analysis based on SNPs detected by RNA sequencing revealed two divergent lineages, UmbL1 and UmbL2. The main differences between them were in the sizes of spikes and spikelets, and culm diameter. UmbL1 is divided into two sublineages, UmbL1e and UmbL1w. These genetic differences corresponded to geographic distributions. UmbL1e, UmbL1w, and UmbL2 are found in Turkey, Iran/Iraq, and Greece, respectively. Although UmbL1e and UmbL1w were genetically similar, flowering time and other morphological traits were more distinct between these sublineages than those between the lineages. This discrepancy can be explained by the latitudinal and longitudinal differences in habitats. Specifically, latitudinal clines of flowering time were clearly observed in Ae. umbellulata, strongly correlated with solar radiation in the winter season. This observation implies that latitudinal differences are a factor in differences in the flowering times of Ae. umbellulata. Differences in flowering time could influence other morphological differences and promote genetic divergence between sublineages.

Management of Seeding Rate and Nitrogen Fertilization for Lodging Risk Reduction and High Grain Yield of Mechanically Direct-Seeded Rice under a Double-Cropping Regime in South China

Precision hill-drop direct seeding using mechanical drilling is a unique direct seeding technique employed in south China that offers advantages such as excellent grain yield and high lodging resistance. Improving yield and lodging-related traits is essential for efforts to improve mechanically direct-seeded rice (MDSR) production. Seeding rates (SR) and nitrogen (N) fertilization rate are two of the main factors affecting grain yield and lodging resistance under MDSR production. However, little information about double-season MDSR production in south China is available. Here, we evaluated yield and lodging risk for two rice cultivars Huanghuazhan, HHZ, lodging-resistant; Xiangyaxiangzhan, XYXZ, lodging-susceptible across two consecutive growing seasons under two under two seeding rates (LSR, 30 cm × 18 cm; HSR, 30 cm × 12 cm) and three N fertilization rates (N1 = 100 kg ha−1, reduced N; N2 = 150 kg ha−1, normal N; and N3 = 200 kg ha−1, enhanced N). We found that increased SR and N fertilization rate improved grain yield and increased lodging risk. SR and N were consistently and positively related to plant height (PH), gravity center height (GCH), the length from the broken basal internode to the panicle tip (SL), the fresh plant weight of the plant part above the broken point (FW), and the length of the two basal internodes. SR and N decreased breaking force (F) and breaking strength (BM), driving increased lodging risk as reflected by increases in lodging index (LI) values. Culm diameter (CD) and culm wall thickness (CWT) did not respond consistently to SR and N treatments. Correlation analysis revealed that PH, GCH, the length of first and second basal internodes, FW, and bending moment for the whole plant (WP) were positively correlated with LI, while F and BM were negatively associated with LI. These findings suggest that the increased lodging risk resulting from high SR could be mitigated by applying appropriate rates of N; that is, this work suggests that grain yield can be maximized and lodging risk minimized by increasing SR while decreasing N fertilization rate. Seasonal differences in the effects of SR and N fertilization should be considered to achieve a high grain yield and maintain high lodging resistance. Our study suggests that increasing SR and decreasing N fertilization can enhance rice grain yield while improving lodging resistance for both varieties. Optimizing grain yield by increasing SR while reducing lodging risk by lowering N application rates may maintain lodging resistance and improve grain yield.

Fishpole Bamboo [Phyllostachys aurea (Andre) Riviere and C. Riviere] in the Philippines: Its Properties and Potential Utilization

This study focused on assessing the morphological, anatomical, and physico-mechanical properties of fishpole bamboo [Phyllostachys aurea (André) Rivière and C.Rivière] grown in Baguio City, the Philippines. The aim of this study was to establish baseline information about these properties and recommend potential applications beyond ornamental use. The results showed that the relative density, modulus of rupture, and stress at the proportional limit of the fishpole bamboo were higher than those of commercial bamboo species. In terms of morphological properties, the culm diameter and culm wall thickness tended to decrease significantly by 64.0 and 39.96%, respectively, toward the top portion. In contrast, the internode length increased significantly from bottom to middle by 41.57%. With respect to anatomical properties, the fiber length, fiber and lumen diameter, and cell wall thickness significantly decreased from bottom to top by 14.89, 13.63, 23.32, and 10.67%, respectively. Conversely, its relative density and radial shrinkage significantly increased by 23.06% and 26.77%, respectively, toward the top. Regarding the mechanical properties, the modulus of rupture, stress at the proportional limit, and modulus of elasticity increased significantly by 62.41, 88.25, and 45.51% from the bottom of the culm to the top, respectively. However, the compressive strength (29.40 MPa) and shear strength (2.83 MPa) deviated from this trend. Fishpole bamboo can be employed as a raw material for furniture, window frames, and handicrafts, wherein a large diameter is not required. Additionally, it can be used for canes, walking sticks, umbrella and fan handles, and souvenir materials. Notably, culms with diameters exceeding 5.0 cm can be used as raw materials for laminated and engineered bamboo. They can also be used as raw materials for preparing pellets and briquettes.

Sorghum Densification with Changes in Plant Spacing Arrangement: Productivity and Qualitative Characteristics of Silage Material

The aim of this study was to evaluate the agronomic performance of sorghum grown in different combinations of row spacing and plant density, as well as possible interferences on silage quality. No other study dedicated to identifying the interference of plant spatial arrangement on the cultivation of silage material has been developed in the productive context of the Amazon Biome, making it necessary to understand the behavior of the studied factors. The treatments were arranged in a split-plot scheme: the plots corresponded to three row spacings (0.45 m, 0.60 m, and 0.75 m) and subplots at four densities (105,000, 120,000, 135,000, and 150,000 plants ha−1). The agronomic and productivity characteristics of sorghum and the fermentative and bromatological characteristics of forage and silage were evaluated. The sorghum plants showed an increase in plant height and green and dry mass yield when using higher densities (p &lt; 0.05). For the culm diameter variable, an isolated effect of the factors was observed, with reduced diameter when grown closer to inter-row spacing or using higher plant densities. No effect of the factors was found (p &gt; 0.05) for morphological plant components. In silage, wider spacing promoted higher dry matter content. Regarding crude protein in the silage, higher percentages were obtained at closer spacing and higher plant density. The sorghum growing in dense conditions is indicated, given the positive performance in productivity and bromatological composition.

Biomass Storage Potential and Improvement in Soil Properties under Different Bamboo Plantations in the Terai Region of Central Himalaya

This study evaluates six bamboo species, i.e., Dendrocalamus hamiltonii, Bambusa nutans, Dendrocalamus asper, Bambusa bambos, Bambusa balcooa, and Dendrocalamus strictus, regarding their growth behavior, nutrient uptake, and effect on the soil properties of the Terai region. Various aboveground growth parameters exhibited significant variations with the maximum clump girth (8.60 m) and internodal length (35.37 cm) of B. nutans, which was also reported by the culm diameter (5.70 cm) of D. hamiltonii and the number of culms per clump (65) of D. strictus. The total aboveground biomass ranged from 51.14 Mg.ha-1 in D. asper to 362.56 Mg.ha-1 in D. hamiltonii. The most significant variation in soil properties was observed in the 0-40 cm soil layer. Under D. hamiltonii, the lowest soil bulk density (1.07 g.cm3; 1.21 g.cm3) and the maximum soil porosity (59.00%; 56.40%), soil organic carbon (1.54%; 0.72%), and available soil nitrogen (228.29 kg.ha-1; 173.73 kg.ha-1) were found the 0-40 and 40-80 cm soil layers. Furthermore, significant enhancements in soil microbial population were recorded. Thus, bamboo plantations have great potential to enhance the biomass generation and fertility quotient of fallow lands.

Survivorship and Field Growth Characteristics of Four Selected Bamboo Species for The Development of Bamboo Industry in Sarawak, Malaysian Borneo

The Sarawak State Government has assigned the Sarawak Timber Industry Development Corporation (STIDC) to lead the development of the bamboo industry in Sarawak. Since bamboo research in Sarawak has received meagre attention, baseline information on the early survival rate and field growth characteristics of bamboo are essential for the development of the bamboo industry. A study to evaluate the survivorship and field growth characteristics of a three-year-old bamboo was conducted at the Sarawak Bamboo Pilot Project site in Sabal, Malaysia. Study plots were established at bamboo plantation areas with four different potential bamboo species grown in Sarawak, namely Bambusa vulgaris (Buluh minyak), Gigantochloa levis (Buluh beting), Gigantochloa hasskarliana (Buluh beti), and Dendrocalamus asper (Buluh betong). Survival rate and field growth characteristics in terms of the number of culms per clump, the number of new shoots, culm diameter, culm height, mean annual increments of diameter (MAID), and height (MAIH) were measured and quantified quarterly in the year of 2021. The findings revealed that the highest mean survival rate (88%) was found in G. levis, and the lowest survival rate (70%) was found in G. hasskarliana. However, the lowest mean culm diameter was observed in G. levis at 2.66 cm, and the highest was in B. vulgaris at 4.51 cm. Notwithstanding, B. vulgaris remained with the greatest mean culm height of 12.61 m. Nonetheless, G. hasskarliana depicted the highest number of culms per clump and shoots with 91 culms and 3 shoots, respectively. The MAID and MAIH of B. vulgaris were significantly higher than the other species with 1.69 cm year-1 and 4.72 m year-1, respectively. The scientific information and findings from this study would be useful as guidelines for bamboo industry players, managers, nursery practitioners, and policymakers to begin and carry out the development of the bamboo industry, mainly in Sarawak.

Screening of potential donors for anaerobic stress tolerance during germination in rice.

The rising cost of transplanting rice has made direct seeding an affordable alternative for rice establishment, particularly in Africa. However, direct seeding, while cost-effective, faces crop establishment challenges due to flooding. Uncontrolled water, driven by erratic rains in low-lying areas or uneven fields, limit germination. Rice possesses the unique ability of anaerobic germination, enabling it to sprout and emerge in oxygen-deprived conditions. Understanding rice's response to anaerobic stress during germination is crucial for resilience breeding. Africa, although relying on direct seeding, has made limited progress in addressing flooding during germination compared to Asia. Anaerobic stress tolerance ensures successful crop emergence even in oxygen-limited environments and can help suppress weeds, a significant challenge in direct-seeded rice cultivation. This study aims to contribute by screening for potential rice donors exhibiting anaerobic stress tolerance. We screened 200 rice genotypes at Sokoine University of Agriculture (SUA) in Morogoro, Tanzania, primarily focusing on landraces with untapped potential. Using an alpha lattice design, we conducted two anaerobic experiments in September and October 2022, adding 7cm of standing water immediately after dry seeding for flooded and maintaining a 2cm water level after germination in the control for duration of 21 days. We identified potential donors based on selection index computed from genomic estimated breeding values (GEBVs) using eight variables: germination at 14 DAS, germination at 21 DAS, seedling height at 14 DAS, seedling height at 21 DAS, shoot dry matter at 21 DAS, root dry matter at 21 DAS, culm diameter at 21 DAS, and root length at 21DAS. Ten genotypes emerged as the most promising, exhibiting at least 70% germination in floodwater at 21 DAS and greater selection indices. These genotypes were like: Afaa Mwanza 1/159, Rojomena 271/10, Kubwa Jinga, Wahiwahi, Magongo ya Wayungu, Mpaka wa Bibi, Mwangaza, Tarabinzona, IB126-Bug 2013A, and Kanamalia with respective percentages of 75, 74, 71, 86, 75, 80, 71, 80, 70, and 73. These findings contribute to global efforts to mitigate the impacts of flooding during germination. These donors, will be potential to enrich the gene pool for anaerobic germination, providing valuable resources for breeding for flooding tolerance.

The transcription factor MYB110 regulates plant height, lodging resistance, and grain yield in rice.

The high-yielding Green Revolution varieties of cereal crops are characterized by a semidwarf architecture and lodging resistance. Plant height is tightly regulated by the availability of phosphate (Pi), yet the underlying mechanism remains obscure. Here, we report that rice (Oryza sativa) R2R3-type Myeloblastosis (MYB) transcription factor MYB110 is a Pi-dependent negative regulator of plant height. MYB110 is a direct target of PHOSPHATE STARVATION RESPONSE 2 (OsPHR2) and regulates OsPHR2-mediated inhibition of rice height. Inactivation of MYB110 increased culm diameter and bending resistance, leading to enhanced lodging resistance despite increased plant height. Strikingly, the grain yield of myb110 mutants was elevated under both high- and low-Pi regimes. Two divergent haplotypes based on single nucleotide polymorphisms in the putative promoter of MYB110 corresponded with its transcript levels and plant height in response to Pi availability. Thus, fine-tuning MYB110 expression may be a potent strategy for further increasing the yield of Green Revolution cereal crop varieties.

Adaptation and Growth Performance of Different Introduced Lowland Bamboo Species in Central Tigray, Ethiopia

Aim of study: The study was performed to evaluate the growth performance and adaptation potential of different exotic lowland bamboos, as well as identifying and providing the best-performing species. &#x0D; Area of study: The study was conducted in Agbe, Tanqua Melashe district Central Tigray between June 2018 and December 2021. &#x0D; Material and methods: The study focused on six different exotic lowland bamboo species, which are Dendrocalamus hamiltonii, Dendrocalamus asper, Dendrocalamus membranaceos, Bambusa vulgaris, Bambusa bambos, and Guadua amplexifolia. The experiment was designed as a randomized complete block design (RCBD) with three replications. An analysis of variance was used to analyze the collected data.&#x0D; Main results: The selected bamboo species somehow had problems with survival and adaptability except for Bambusa bambos, Bambusa vulgaris, Dendrocalamus membranaceos, and Dendrocalamus hamiltonii species. Between species’ parameters, such as root collar diameter, culm diameter, culm height, and number of culms, the outcome had a significant difference at (p

QTL Mapping of Tiller Number in Korean Japonica Rice Varieties.

Tiller number is an important trait associated with yield in rice. Tiller number in Korean japonica rice was analyzed under greenhouse conditions in 160 recombinant inbred lines (RILs) derived from a cross between the temperate japonica varieties Odae and Unbong40 to identify quantitative trait loci (QTLs). A genetic map comprising 239 kompetitive allele-specific PCR (KASP) and 57 cleaved amplified polymorphic sequence markers was constructed. qTN3, a major QTL for tiller number, was identified at 132.4 cm on chromosome 3. This QTL was also detected under field conditions in a backcross population; thus, qTN3 was stable across generations and environments. qTN3 co-located with QTLs associated with panicle number per plant and culm diameter, indicating it had pleiotropic effects. The qTN3 regions of Odae and Unbong40 differed in a known functional variant (4 bp TGTG insertion/deletion) in the 5' UTR of OsTB1, a gene underlying variation in tiller number and culm strength. Investigation of variation in genotype and tiller number revealed that varieties with the insertion genotype had lower tiller numbers than those with the reference genotype. A high-resolution melting marker was developed to enable efficient marker-assisted selection. The QTL qTN3 will therefore be useful in breeding programs developing japonica varieties with optimal tiller numbers for increased yield.

Aboveground Biomass Productivity and Nutrient Use Dynamics of Clumping Tropical Bamboos in Northern Thailand

Bamboo has great potential in restoring degraded lands while providing multiple environmental benefits and harvestable products at regular intervals due to its unique characteristics of rapid growth. However, a comprehensive and species-specific knowledge of biomass productivity, nutrient dynamics, and potential harvest-induced nutrient losses is lacking. This study compared the biomass and nutrient dynamics of four bamboo species Bambusa oldhamii Munro, Dendrocalamus latiflorus Munro, Bambusa tulda Roxburgh, and Dendrocalamus brandisii (Munro) Kurz in Northern Thailand. Field measurements, laboratory analyses, and statistical modeling were used to estimate their aboveground biomass (AGB), nutrient use efficiency (NUE), and nutrient stocks. Culm diameter at breast height (DBH) and age were identified as the most reliable predictors of AGB. The study revealed that D. brandisii had superior productivity and NUE compared to the other species, particularly the introduced non-native bamboo species. These findings emphasize the need for species-specific strategies that consider both biomass productivity and nutrient dynamics. Furthermore, D. brandisii can be suggested as a native candidate for bamboo plantations in Northern Thailand and similar environments, given its high productivity and efficient nutrient use, underpinning its potential contribution to environmental rehabilitation and rural livelihoods. However, more research is required to minimize nutrient losses and maintain a productive age structure.

Growth and biomass production of five exotic bamboo species in North-western Ethiopia

Forests provide goods and services and the demand for these has increased over the years. To meet this demand, reforestation using fast-growing species is crucial. Bamboo is amongst the fastest-growing plant species. Consequently, the Ministry of Agriculture/East Africa Bamboo Project and the European Union Energy Project/INBAR introduced twenty-three bamboo species to Ethiopia. This study assessed the growth and biomass production potential of five of these exotic bamboo species (Dendrocalamus membranaceus, Dendrocalamus asper, Dendrocalamus hamiltonii, Bambusa vulgaris and Guadua amplexifolia). A randomized complete block design (RCBD) with three replications was used. Nine seedlings of each species were planted per plot using two meters spacing between and within rows. Sprouted culms per clump, culm length, culm diameter at breast height (DBH), average number of nodes and internode length per culm were measured. At age of 3½ years after planting, one clump of each species per plot in each block was uprooted and sorted into different components (rhizome, culm, branch and leaves). The fresh weight of each component was measured and sub-samples were taken to dry to constant weight. One-way ANOVA and then Tukey's test were used to find significantly different group means. The growth performance, in terms of culm production, culm height, internode length and biomass production, of the species was significantly different. D. asper and D. hamiltonii had superior growth and biomass production. We therefore recommend planting these two species in Guangua district and other similar areas where they can enhance the livelihoods of the communities.

The potential of bamboo forests as a carbon sink and allometric equations for estimating their aboveground biomass

Bamboo forests in Colombia and the Andean region of South America represent high-value ecosystems that provide ecological and economic benefits with local and global impacts. One of the ecosystem services provided by these forests is associated with their capacity to store carbon. In this study, data collected from monitoring plots were used to estimate the carbon content in different pools. Bamboo biomass (Bba), tree biomass (Btree), litter (Cli) and soil organic carbon (SOC) were assessed. The approximate total ecosystem carbon stock (TECaprox) ranged from 198.4 Mg C ha−1 to 330.9 Mg C ha−1 and bamboo carbon Cba represents approximately 50%. In addition, considering the relevance of developing tools to facilitate bamboo inventory and biomass estimates, allometric equations (AE) to estimate bamboo aboveground biomass (AGB) were fitted using the diameter of culms at breast height (dbh) and the total culm length (l) as predictor variables. The fitted AEs included the weighted linear, weighted log-transformed and weighted nonlinear fixed effect models. To compliance the additivity of biomass components a simultaneous systems of biomass equations (seemingly unrelated regressions) were also fitted. The precision and accuracy were assessed considering the residual diagnostic plots and statistics, such as the root-mean-square error (RMSE), RMSE percentage error (RMSEPE) and the Furnival’s index (Fln) for weighted log-transformed models and cross-validation. The performance of the models was similar with an RMSE of approximately 10 kg and 26% of RMSEPE, with slightly lower error for the weighted log-transformed model for the fitting and validation phases. A proper performance was also evidenced for the simultaneous approach for predicting AGB. Bamboo forests showed high relevance as carbon sinks and therefore might be considered strategic tropical ecosystems for climate change mitigation. On the other hand, the fitted AE exhibited proper performance and therefore provided reliable possibilities for estimating the AGB of bamboo during inventories. For practical reasons, the use of models with dbh as a predictor variable is recommended.

Foliar spray of stress protective chemicals alleviates cobalt toxicity by improving root antioxidant defense in maize (Zea mays).

Cobalt (Co2+) is a beneficial microelement for plants but toxic to metabolism in higher amounts. This study determined the influence of sublethal Co2+ level (0.5mM) on the growth of maize (Zea mays L.) hybrids; Hycorn 11 plus (Co2+ sensitive) and P-1429 (Co2+ tolerant) and its alleviation with foliar spray of pre-optimized levels of stress protective chemicals (SPCs), i.e., salicylic acid (SA, 0.5mM), thiourea (TU, 1.0mM), and ascorbic acid (AsA, 0.5mM) applied at seedling, vegetative, and late vegetative stages. Plants were harvested at early vegetative, late vegetative, and silking stages. Co2+ stress caused a decrease in shoot and root length, dry weight, leaf area, and culm diameter, reduced the activities of enzymatic antioxidants and concentrations of AsA and soluble phenolics more in root than shoot, but P-1429 was more tolerant of Co2+ than Hycorn 11 plus. SPCs spray alleviated oxidative damage by enhancing the antioxidant activity, AsA and soluble phenolics, sulfate-S and nitrate-N contents, which were significantly increased in roots than in shoots; P-1429 displayed better response than Hycorn 11 plus. Principal component analysis and correlation matrix revealed the profound roles of SPCs spray in improving Co2+ resistance in root leading to robust growth of hybrids. AsA was highly promising in reducing Co2+ toxicity while vegetative and silking stages were more sensitive. Results revealed that after translocation to root, the foliar-applied SPCs had individualistic modes of action in mitigating Co2+ toxicity on roots. In crux, the metabolism and phloem transport of the SPCs from shoot to root are plausible mechanism for Co2+ tolerance in maize hybrids.