Within the framework of a project entitled “Development of Advanced Sweet Potato Cultivation Technology for Smallholder Farmers in Paraguay” implemented by KOPIA Paraguay Center (Korea Partnership for Innovation of Agriculture) in collaboration with Paraguayan Institute of Agricultural T echnology (I PTA) d uring the period 2021-2024, r esults o f four m ain e xperiments are described in this research: selection of suitable varieties, optimal planting and harvesting times, the use of ridges, and optimal chemical fertilization doses. In the selection of suitable varieties for Paraguay, 11 sweet potato varieties were evaluated in departments of San Pedro and Misiones. As a result, varieties Andaí, Jety Paraguay, and Chaco I showed the highest productivity in San Pedro, while varieties Jety Uruguayo, Chaco I, and Taiwanés showed higher productivity in Misiones. The other three experiments were carried out in San Pedro only. Optimal planting and harvesting times were determined with three varieties: Andaí, Pyta Guasu, and Jety Paraguay. For Andaí and Jety Paraguay varieties, they should be planted in December and harvested at 122 days post planting (DPP). For Pyta Guasu, it should be planted in October and harvested at 124 DPP. Regarding productivity response with soil preparation methods, the use of ridges showed higher yields in all planting methods, with the curved method planting being the most productive. Finally, optimal chemical fertilization doses were established in order to improve the total yield. The optimal nitrogen fertilizer dose (urea 45% N) was 40 kg/ha. The optimal phosphorus fertilizer dose (triple superphosphate 45% P2O5) was 80 kg/ha and the optimal potassium fertilizer dose (potassium chloride 60% K2O) was 120 kg/ha.

Sweet potato (Ipomoea batatas L.) is an essential crop in the Paraguayan diet. It plays a crucial role in food security. It is a source of income for family agriculture. It has a significant potential to adapt to various climatic and soil conditions in Paraguay, making it a promising crop for improving productivity. However, Paraguay faces a deficit in the development of sweet potato cultivation technology, resulting in a low productivity of 5.3 ton/ha. Efforts have been made to collect and characterize sweet potato genotypes, covering a diversity of native varieties. These efforts have laid the groundwork for future sweet potato research and development. Still, ongoing research and development of strategies are needed to address existing challenges of improving genetic resource traits and developing cultivation technology and to fully exploit growth opportunities in this sector. This review summarizes sweet potato cultivation in Paraguay, focusing on several key technical aspects. It analyzes current market situation and production conditions as well as the availability of genetic materials adapted to different ecoregions. Additionally, it explores prospects for the development of advanced sweet potato crops, including the production of high-quality, virus-free sweet potato plants with improved productivity.

As part of the KOPIA Paraguay Center rice pilot villages project, conducted from July 1, 2021, to the end of June 2024, this study examined the average yield and value of paddy rice harvested between January and April 2023 in five local rice pilot villages in Paraguay: Santa Rosa, Eusebio Ayala, Coronel Bogado, Santa Maria, and Yaguaron. The CEA-5K-PUNTA variety was planted in late August 2022 and subsequently harvested from January to April 2023. The farmers in the pilot villages received information on common pests, diseases, and weeds, including instructions on timing and the number of applications required for their control. They also received technical guidance on water management and weeding methods. The study found that the average yield per hectare in the pilot villages for the CEA-5K PUNTA variety in the 2022/2023 growing season was 794.50 kg/10a, compared to 477.17 kg/10a for the conventional variety IRGA 424 in the 2019/2020 season, which preceded the project. This indicates a 66.5% increase in yield per hectare for the pilot village farmers compared to the pre-project period (2020/2021). The analysis of paddy rice production value in the pilot villages, using the Difference in Differences method, revealed a 65.1% increase. Moreover, a financial analysis was conducted based on the addition of agricultural inputs to the paddy fields during the period from the end of August 2022 to January-April 2023. The analysis showed that the total cost was US$597.25 per hectare, while the gross income was US$1,685.3 per hectare. As a result, the net profit per hectare amounted to US$1,088.05.

2010년에 호접란에서 꽃봉오리 낙화를 동반하는 꽃대가 괴 사증상을 나타내는 바이러스로 추정되는 피해가 상업용으로 호접란을 재배하는 경기도 화성지역 농가에서 ‘Fireweak’ 단 일 품종에서 백만주 가량 발생하였다. 난에 발생하는 주요 바 이러스 특이 프라이머를 이용하여 RT-PCR한 결과 ORSV와 CymMV 프라이머 특이 PCR 산물이 증폭되었으며 이 두 개 의 분리주를 각각 ORSV-NIHHSK2와 CymMV-NIHHSK2로 명명하였다. ORSV-NIHHSK2를 ORSV 48개의 국내 분리주 (GenBank accession no. AB541474-AB541521)와 염기서열 상동성을 비교한 결과 98.3~100%이며 아미노산 서열 상동성 은 97.5~100%이었다. CymMV-NIHHSK2를 52개의 CymMV 국내 분리주(GenBank accession no. AB541522-AB541573) 와 염기서열 상동성을 비교한 결과 90.2~100%, 아미노산 서 열 상동성은 96.0~100%이었다. 바이러스에 감염되지 않은 ‘Fireweak’ 품종을 포함하는 6개 계통에 ORSV-NIHHSK2과 CymMV-NIHHSK2 이병즙액을 인공 접종하여 2년 동안 병징 발현을 관찰한 결과 ‘Fireweak’ 품종에서 꽃이 봉오리 상태에 서 노랗게 말라 죽는 증상을 동반하는 꽃대 괴저증상이 접종 주 총 18 그루 가운데 2 그루에서 관찰되었으며, 잎에 황색반 점 및 괴저 증상을 나타내었다. 따라서 ‘Fireweak’ 품종에서 나타내는 꽃대 괴저 증상은 ORSV와 CymMV 단독 또는 복합 감염에 의한 증상임을 보여주었다. 이 결과로부터 호접란 꽃 대 괴저증상은 ORSV 또는 CymMV 감염에 민감한 품종에서 나타나는 것으로 추정되었다. 이 연구는 호접란에서 ORSV 또 는 CymMV 감염에 의한 화기의 괴저 증상에 관한 세계 최초 보고이다.

Freesia is one of the most popular flowers over the world including Korea, due to the fragrance and beauty of the plant flower. The first domestic freesia cultivar ‘Shiny Gold’ was developed by NIHHS, RDA, in 2003, which has yellow double and large petals and strong fragrance. Ten years have passed since ‘Shiny Gold’ was cultivated at floral farms, and the deterioration of cut flower quality and yield are reported from the farms. Virus infection causes a reduction in the quantity and quality of the cut freesia flowers and is one of the most serious problems in Korea. Virus detection was carried by reverse transcription polymer chain reaction (RT-PCR) for FreMV, FreSV, BYMV, CMV, and TRV, as known to infect freesia. FreMV, FreSV, BYMV, and TRV were detected single or multiply, and CMV was not found in the freesia leaves collected from the farms. To produce virus-free freesia, meristem culture of ‘Shiny Gold’ was conducted in MS medium added ribavirin at different concentration. As the increased of ribavirin concentration, the growth of ‘Shiny Gold’ plantlets was inhibited in freesia’Shiny Gold’. The plantlets produced by meristem culture in ‘Shiny Gold’ were virus free at the enzyme-linked immunosorbent assay (ELISA) level.

Tsw, a single dominant resistant gene against Tomato spotted wilt virus (TSWV), has been mapped on chromosome 10 in Capsicum chinense species. Previously reported molecular markers linked to the Tsw gene are not transferable for all pepper breeding materials. To develop additional markers and do genome-based fine mapping of the Tsw gene, approaches of mapping comparison, pooled transcriptome analysis, and genome walking were applied. Eleven additional SNP molecular markers tightly linked to the Tsw gene were developed using tomato and pepper whole genome sequencing databases. Among them, four SNP markers, SNP7715-1, SNP68-1, SNP17918-1, and SNP1072-1, showed no recombination in two segregating populations of F2 ‘Telmo’ (210 individuals) and ‘SP’ (843 individuals). Three scaffold sequences from the C. annuum BAC database and two BAC clones from the BAC library of C. annuum ‘CM334’ covering the Tsw gene were identified by transcriptome analysis and genome walking. A pepper scaffold sequence covering three pepper scaffold sequences was identified from a final version of the C. annuum BAC database. The Tsw gene was delimited within 149 kb by alignment analysis of two BAC clone sequences and the pepper scaffold sequence. A total of 22 predicted genes were resided in the target region between SNP7715-1 and SNP1072-1 co-segregating markers. Among them, five predicted genes showing annotations of CC/TIR-NBS-LRR resistance proteins, mRNA-6, mRNA-7, mRNA-11, mRNA-12, and mRNA-13, were identified. The transcriptome analysis and gene expression study showed that the mRNA-13 was expressed in ‘PI152225’ but was absent in ‘Special’, demonstrating the mRNA-13 could be a strong candidate gene for the Tsw gene. This result will be favorable for cloning the Tsw gene and developing cultivars which carry the TSWV-resistance gene.

본 연구는 고온에 안정적인 TSWV 저항성 유전자원을 선발하기 위해 수행되었다. 우선, 저항성 검정조건을 마련하고자 8점의 TSWV 저항성 육성계통을 두 가지 온도 조건(주간 25℃ ± 3.1℃, 35℃ ± 2.2℃)에서 검정을 실시하였다. 8점 중 두 계통(11VR35와11VR51)은 25℃에서 이병율이 모두 0.0%이었으나 35℃에서는 각각 100%, 80%의 이병율을 보였다. 아울러11VR32 11VR47 11VR53 11VR54 는 25℃에서 이병율이28.6%, 37.5%, 10.0%, 10.0%를 보여 중도저항성으로 평가되었으나 35℃에서는 이병율이 모두 100%로 나타났다. 이러한 결과는 고온(30℃ 이상)에서 저항성이 변화한다는 기존 보고와 유사한 결과를 확인할 수 있었다. 따라서 TSWV저항성 검정은 고온에서 실시하는 것이 안정적이라고 판단되었다. 이러한 조건으로 저항성검정을 실시한 결과 5점의 TSWV 저항성 유전자원을 선발하였다. 5점의 TSWV 저항성 유전자원은 2 C.annuum (11PM25, 11PM28), 3 C.chinense (11FL34, 11FL38, 11FL44)이다. 그러나 이들은 Tsw에 의한 과민반응(hypersensitivity response; HR)과 같은 증상은 없었다. 따라서 5점의 TSWV 저항성 유전자원은 TSWV 저항성 품종육성에 새로운 저항성 재료로 사용될 것으로 기대된다.

The Cmr1 gene in peppers confers resistance to Cucumber mosaic virus isolate-P0 (CMV-P0). Cmr1 restricts the systemic spread of CMV-Fny, whereas this gene cannot block the spread of CMV-P1 to the upper leaves, resulting in systemic infection. To identify the virulence determinant of CMV-P1, six reassortant viruses and six chimeric viruses derived from CMV-Fny and CMV-P1 cDNA clones were used. Our results demonstrate that the helicase domain encoded by CMV-P1 RNA1 determines susceptibility to systemic infection. To identify the key amino acids determining systemic infection with CMV-P1, we then constructed amino acid substitution mutants. Of the mutants tested, amino acid residues at positions 865, 896, 957, and 980 in the 1a protein sequence of CMV-P1 affected the systemic infection. Virus localization studies with CMV-GFP clones and in situ localization of virus RNA revealed that these four amino acid residues together form the movement determinant for CMV-P1 movement from the epidermal cell layer to mesophyll cell layers. Quantitative real-time PCR revealed that CMV-P1 and a chimeric virus with four amino acid residues of CMV-P1 accumulated more genomic RNA in inoculated leaves than did CMV-Fny, indicating that those four amino acids are also involved in virus replication. These results demonstrate that the helicase domain is responsible for systemic infection by controlling virus replication and cell-to-cell movement. Whereas four amino acids are responsible for acquiring virulence in CMV-Fny, six amino acid (positions at 865, 896, 901, 957, 980 and 993) substitutions in CMV-P1 were required for complete loss of virulence in ‘Bukang’.

Tsw, a single dominant resistant gene against Tomato spotted wilt virus (TSWV), has been mapped on chromosome 10 in Capsicum. Previously found molecular markers linked to the Tsw gene are not transferable for all pepper breeding materials. To develop segregating populations for the Tsw, commercial F1 cultivar C. annuum ‘Telmo’ was self-pollinated. An F2 population was obtained from the self-pollination of F1 plants deriving from a cross between C. annuum ‘Special’ and C. chinense ‘PI152225’. Twelve additional molecular markers linked to the Tsw gene were developed using tomato and pepper genome sequence database. A tomato scaffold sequence of 7841 kb in size covering the corresponding region of the Tsw locus was identified based on the sequence of Tsw-linked marker. Analyzing the tomato scaffold sequence, two sequences of pepper scaffold and contig at down and up site of the Tsw locus, respectively, were located. Three SNP markers linked to the Tsw locus (HRM1, HRM2, and HRM3) were developed using the pepper scaffold sequence of 419 kb in size. All three markers showed 2 recombinants (1.0 cM) out of 198 individuals of F2 ‘Telmo’ population. When analyzing these SNP markers in an F2 population deriving from C. annuum ‘Special’ and C. chinense ‘PI152225’, we detected 5 recombinants (0.76 cM) out of 659 individuals. HRM4, a SNP marker linked to the Tsw gene, was developed with a 99 kb pepper contig sequence. It showed 7 recombinants (3.5 cM) out of 198 individuals of F2 ‘Telmo’ population. We found 5 recombinants (0.76 cM) out of 659 individuals when HRM4 was analyzed in F2 population derived from C. annuum ‘Special’ and C. chinense ‘PI152225’. To narrow down the molecular markers linked to the Tsw locus, four SNP markers, HRM5, HRM6, HRM7, and HRM8, were developed with the pepper scaffold sequence. All of them showed 5 recombinants (0.76 cM) out of 659 individuals of F2 ‘SP’ population. Four other SNP markers, HRM9, HRM10, HRM11, and HRM12, were developed using the pepper contig sequence. HRM9 showed 5 recombinants (0.76 cM), HRM10 showed 4 recombinants (0.61 cM), and HRM11 and HRM12 showed 3 recombinants (0.46 cM) out of 659 individuals of F2 ‘SP’ population. The SNP markers developed in this study will be useful for fine mapping of the Tsw gene and for developing cultivars which carry TSWV-resistance gene.

A new graft cactus (Gymnocalycium marsoneri x mihanovichii x G. mihanovichii) cultivar, 'Hwangjo' was developed from a interspecific cross between an orange colored G. marsoneri x mihanovichii breeding line '9834036', a line with characteristics of vigorous growth and stable color under the strong sun light, and an orange colored graft cactus (G. mihanovichii) breeding line 'IG177' and through line selection at the National Horticultural Research Institute, Rural Development Administration in 2005. It was developed with the aim to breed a bright and vivid orange colored cultivar. Its characteristic evaluation was conducted three times during 2003 to 2005. The color of both body and tubercle was yellow. The shape of globe was flattened round and it had 8 to 10 deep ribs. The spine was semi erect, medium sized and grayish brown color. Growth was faster than the comparison cultivar, 'Hugwang'. Propagation capability was excellent, setting 15 tubercles per globe. Characteristics of the cultivar could be maintained by vegetative propagation. Strong sun light and virus infection should be avoided.

A new graft cactus (Gymnocalycium mihanovichii) cultivar, 'Simhong' was developed from a cross between graft cactus breeding line 'Keumhong', a cultivar revealing a red colored globe with yellow colored tubercles, and a dark red line '9502052' and consecutive line selection at the National Horticultural Research Institute, Rural Development Administration in 2005. It was developed with the aim to breed a dark red cultivar. Its characteristic evaluation was conducted three times during 2003 to 2005. The color of both body and tubercle was dark red. The shape of the globe was flattened round and it had 8 to 10 deep ribs. The spine was medium sized, straight and dark brown. Its growth was faster than the comparison cultivar, 'Jinhong'. Propagation capability was excellent, setting 12 tubercles per globe. Characteristics of the cultivar could be maintained by vegetative propagation. Strong sun light and virus infection should be avoided.

A new graft cactus (Gymnocalycium mihanovichii x G. marsoneri x mihanovichii) cultivar, 'Yeonsim' was developed from a interspecific cross between two black with pink graft cactus (Gymnocalycium mihanovichii) breeding line '9603026' and G. marsoneri x mihanovichii breeding line 'BP', a line with the characteristics of wide spacing between ribs, and vigorous growth and through line selection at the National Horticultural Research Institute, Rural Development Administration in 2005. It was developed with the aim of breeding cultivars with new colors and globe shapes. Its characteristic evaluation was conducted during 2003 to 2005. The color of both body and tubercle was pink. The shape of the globe was flattened round and it had 7 to 9 deep ribs. The spine was short, straight and brown color. Growth was faster than the comparison cultivar, 'Yeonhwa'. Propagation capability was excellent, setting 12 tubercles per globe. Characteristics of the cultivar could be maintained by vegetative propagation. Strong sun light and virus infection should be avoided.

A new graft cactus (Gymnocalycium mihanovichii) cultivar ‘Suyeon’ was developed from a cross between two pink with black breeding lines ‘9603010’ and ‘9603026’, by line selection at the National Horticultural Research Institute, Rural Development Administration in 2005. It was developed with the aim of breeding a cultivar showing vigorous growth and multiple colors. A line ‘9603010’ was derived from a cross between a black line and a pink line. Investigation into characteristics was conducted three times from 2003 to 2005. The color of both body and tubercle was pink with black. The shape of the globe was round and it had 7 to 9 deep ribs. The spine was short and straight, and its color was brown. Growth was retarded compared to a comparative cultivar ‘Ojack’, on the other hand, showed good propagation capability, setting 11 tubercles per globe. Characteristics of the cultivar could be maintained by vegetative propagation. Growers should take care to protect them from strong sun light and virus infection.

A new graft cactus Chamaecereus silvestrii cultivar “Doldol” was developed from a cross between C. silvestrii cv. “Bosong” and C. silvestrii breeding line “ICS07” by in vitro grafting and line selection at National Horticultural Research Institute, Rural

A new graft cactus (Gymnocalycium schickendantzii × G. mihanovichii) cultivar “Geoseong” was developed from a interspecific crossing between a green G. schickendantzii and G. mihanovichii line “950222” by in vitro grafting and line selection at National H

A new graft cactus (Gymnocalycium mihanovichii) cultivar “Suhong” was developed from a cross between G. mihanovichii cv. “Seolhong” and a line “940623” by in vitro grafting and line selection at National Horticultural Research Institute, Rural Development