http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/91677 2026-04-10T13:04:25Z http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/97597 標題: 透過基因組分析揭示泰國金馬鱗魚 （Tor tambra）的性別相關區域; Uncovering the Sex-Associated Regions in the Thai Mahseer (Tor tambra) through Genomic Analysis 作者: 古欣穎; Joyce Koh Xin Ying 摘要: none; The Thai, or Javan, mahseer (Tor tambra) is a freshwater cyprinid of ecological and economic significance, yet its genomic architecture and mechanisms of sex determination remain poorly understood. This study presents the first long-read only genome assembly for T. tambra using Oxford Nanopore sequencing, revealing indications of a fourth round of whole genome duplication based on genome metrics and Benchmarking Universal Single-Copy Orthologs (BUSCO) completeness. Sex-specific genomic regions were investigated through both k-mer–based and allele frequency–based approaches, with findings supporting an XX/XY sex determination system. A high number of male-specific 60-mers enabled the assembly of putative male-linked contigs. BLASTn analysis of sex-specific contigs uncovered several predicted genes potentially related to development or sex differentiation; however, the absence of canonical sex-determining genes and limited query coverage suggest that these findings should be interpreted with caution. Allele frequency analysis further identified six male-associated scaffolds, suggesting putative Y-linked regions. This study also demonstrates the importance of selecting appropriate k-mer lengths for marker discovery. While the findings provide initial insights into sex-linked genomic features in T. tambra, the exact localization of sex-determining loci remains unresolved. Overall, this research offers a genomic foundation for future studies on sex determination and genome evolution in T. tambra, with potential applications in aquaculture, including non-invasive sex identification and selective breeding strategies. 2025-01-01T00:00:00Z http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/94373 標題: 緬甸氣候變遷背景下的水稻適宜性分析; Rice Suitability Analysis in the Context of Climate Change in Myanmar 作者: Mai Ei Ngwe Zin; Mai Ei Ngwe Zin 摘要: 這項研究深入探討了氣候變遷對緬甸稻米適宜性和產量的影響，採用了代表性濃度路徑（Representative Concentration Pathways, RCPs）2.6和8.5。研究利用生態位模型（MaxEnt軟體）評估了緬甸四個農業氣候區域在三個未來時期（2024-2050、2051-2076、2077-2099）的稻米適宜性，結果顯示在不同氣候情境下，稻米種植潛力存在顯著的區域變異。在RCP 2.6的情境下，適度的升溫和穩定的降水模式普遍支持稻米種植的有利條件。相反，RCP 8.5預測近期將出現顯著升溫及極端高溫事件，降水模式則更為局部化，對中部和南部緬甸等地區造成影響。稻米適宜性分析指出，雖然RCP 2.6傾向於支持稻米種植，但RCP 8.5則帶來了挑戰與意外機遇。具體而言，三角洲地區的適宜性有所改善，中部乾燥區展現出一定的韌性，而沿海區域則需有效的水資源管理，丘陵和山區則面臨複雜的結果。 根據2018-2019年的歷史稻米生產數據，模擬適宜性分數以驗證預測，結果顯示三角洲地區、中部乾燥區的薩卡因省和丘陵區的掸邦預計將維持或超過過去的生產力，而沿海區域在RCP 8.5下的適宜性則顯得不太穩定。研究還針對每個農業氣候區域提出了調整稻米種植日曆的建議，以作為確保緬甸未來稻米生產力的戰略適應措施。; This study examines the impact of climate change on rice suitability and yield in Myanmar using Representative Concentration Pathways (RCPs) 2.6 and 8.5. By applying the Ecological Niche Model through MaxEnt software, the research assessed rice suitability across four agro-climatic zones of Myanmar covering for three future periods (2024-2050, 2051-2076, 2077-2099). Findings reveal significant regional variations in rice cultivation potential under different climate scenarios. Under RCP 2.6, moderate warming and stable precipitation patterns generally support favorable conditions for rice cultivation. Conversely, RCP 8.5 forecasts substantial warming and increased extreme temperature events in the near term, with more localized precipitation patterns impacting regions such as Central and Southern Myanmar. The rice suitability analysis showed that while RCP 2.6 tends to support rice cultivation, RCP 8.5 presents both challenges and unexpected opportunities. Specifically, the Delta Region benefits from improved suitability, the Central Dry Zone shows resilience, the Coastal Zone requires effective water management, and the Hilly and Mountainous Regions face complex outcomes. Historic rice production data (2018-2019) were simulated according to the suitability scores to validate projections, indicating that while the Delta Region and Sagaing Division in the Central Dry Zone and Shan State in the Hilly Zone are expected to maintain or exceed past productivity, the Coastal Zone's suitability is less stable under RCP 8.5. The study also proposes adjusted rice crop calendars for each agro-climatic zone as a strategic adaptation measure to ensure future rice productivity in Myanmar. 2024-01-01T00:00:00Z http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/91678 標題: 無人機RGB影像衍生植生指數預測Humidicola (Brachiaria humidicola)產量和品質; Drone RGB Image-Derived Vegetation Indices to Predict Yield and Quality in Humidicola (Brachiaria humidicola) Grass 作者: ALBERT FRESNIDO ASTILLERO; ALBERT FRESNIDO ASTILLERO 摘要: 飼草是反芻動物營養的重要組成部分，依賴適當的牧場管理。然而，不當的管理會導致過度放牧和牧場生產力的總體下降，從而影響動物的表現。為了防止這種情況發生，畜牧農民需要及時和相關的飼草產量和質量信息。傳統的飼草產量和質量測量方法費時、勞動密集，並且對更廣泛的區域精度較低。利用無人機進行這種應用越來越受歡迎，因為它提供了更多的操作靈活性。然而，先前的研究由於使用覆雜的工作流程和非常昂貴的設備，其應用仍然有限。因此，有必要開展研究，開發一種準確而簡單、使用更便宜的工具、計算效率更高的工作流程。在這項研究中，使用了一架配備RGB相機的DJI Mavic 3 Classic 無人機獲取圖像。從這些圖像中提取了植被指數作為預測變量，開發了一個用於預測飼草產量和質量的多項式多元回歸模型。結果顯示，通過結合線性、二次和三次植被指數，可以從20米的高度高度預測鮮重和幹物質，調整後的R2分別為0.71和0.66。然而，預測粗蛋白和中性洗滌纖維含量的準確性較低，調整後的R2分別為0.48和0.53。這表明了一種替代簡單工作流程、成本效益工具和統計方法在Brachiaria humidicola牧場產量預測中的潛力。; Forages are a significant component of ruminant nutrition, which relies on proper pasture management. However, improper management results in overgrazing and an overall decline in pasture productivity, causing poor animal performance. To prevent this, timely and relevant information on forage yield and quality is necessary for the livestock farmer. Traditional ways of measuring forage yield and quality are laborious, time-consuming, and less accurate for wider areas. Using drones for this application is gaining popularity because it offers more operational flexibility. Previous research still has limited application because, despite promising results, they used complicated workflows and very expensive equipment. Thus, there is a need for research to develop a workflow that is accurate yet simple, uses cheaper tools, and is computationally efficient. In this research, a DJI Mavic 3 Classic drone with an RGB camera was used to obtain images. Vegetation indices were extracted from these images as predictors to develop a polynomial multiple regression model for the prediction of forage yield and quality. Results showed that fresh and dry matter can be highly predicted from 20-meter altitude with an adjusted R2 of 0.71 and 0.66, respectively by combining linear, quadratic, and cubic vegetation indices. However, the predictors have lower accuracy in predicting content of crude protein and neutral detergent fiber, with an adjusted R2 of 0.48 and 0.53, respectively. This demonstrates the potential of an alternative simple workflow, cost-effective tools, and statistical method for yield prediction in Brachiaria humidicola pastures. 2024-01-01T00:00:00Z http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/92029 標題: 水稻幼苗期之鐵耐受性數量性狀基因座定位; Mapping of Quantitative Trait Loci Associated to Fe Stress Tolerance in the Rice Seedling 作者: Aisyah Fitri Rohani; Aisyah Fitri Rohani 摘要: None; Rice (Oryza sativa L.) demand is on the rise worldwide due to population growth, which has forced several countries to increase their production. Excessive iron (Fe) as abiotic stress, which often occurs in several countries, proved to be one of the obstacles in rice production. Screening for varieties tolerant to Fe toxicity would be critical for breeders to identify the varieties with the most desirable performance as donor parents in the breeding program, and for a researcher to develop molecular markers used in the selection process. The first step that needs to be done is to look for the chromosomal region related to Fe toxicity defense mechanism. To search for this region, QTL analysis was carried out. In this experiment, 104 RILs derived from IR64 and Nipponbare were treated with 400ppm Fe2SO4.7H2O for 11 days. Phenotyping was conducted by using two evaluating systems to inspect the leaf bronzing level. The first method is to analyze the Red (R) and Green (G) color channels of the scanned leaf images using Adobe Photoshop CS3, the other is to visually assign bronzing score according to the scale described in Shimizu A. (2009). These two independent phenotyping results were combined with 41,256 SNP markers for QTL analysis. The result from single marker analysis showed a peak marker at 8.98Mb on chromosome 8 and two peak markers at 1.06 Mb on chromosome 1 and 6.01Mb on chromosome 3 for R/G index and leaf bronzing score, respectively. Gene function annotation indicates that two genes in these regions are linked to Fe tolerance through ROS scavenging and two genes are linked to Fe transport. 2022-01-01T00:00:00Z