Honey bees are crucial pollinators for agricultural and natural ecosystems, but are experiencing heavy mortality in Korea due to a complex suite of factors. Extreme winter losses of honey bee colonies are a major threat to beekeeping but the combinations of factors underlying colony loss remain debatable. Finding solutions involves knowing the factors associated with high loss rates. To investigate whether loss rates are related to Varroa control and climate condition, we surveyed beekeepers in korea after wintering (2021–2022 to 2022–2023). The results show an average colony loss rate of 46%(2022) and 17%(2023), but over 40% colony loss before wintering at 2022. Beekeepers attempt to manage their honey bee colonies in ways that optimize colony health. Disentangling the impact of management from other variables affecting colony health is complicated by the diversity of practices used and difficulties handling typically complex and incomplete observational datasets. We propose a method to 1) Varroa mite population Control by several methods , and 2) Many nursing bee put in hive before wintering.

South Korea has over 0.38 million of managed honey bee (Apis cerana) colonies before 2009 years ago, which produce the highest quantity of honey in the Korea; however, almost colony (90%) were collapsed by Korean Sacbrood Virus (KSBV) in South Korea. Korean Sacbrood Virus (KSBV) is the pathogen of A. cerana Sacbrood disease, which poses a serious threat to honeybee A. cerana, and tends to cause bee colony and even the whole apiary collapse. Colony collapse of A. cerana was first reported on the Pyeong-Chang of the South Korea in 2009. Several scientists and governments has been tried research for cure the sacbrood disease in A. cerana colony by medicines and management techniques. Unfortunately, The sacbrood disease dosen’t improve. So, we were developed a better breed of A. cerana for resistance of sacbrood virus by selection and then artificial insemination. A. cerana breeding technique was first successful applied with A. cerana in Korean. Queens was grafted from sacbrood resistance line and then it was growing in sacbrood disease colony that was survived 100%. Altogether selected 18 queens were artificially inseminated and 2,000 drones of A. cerana in Korea was used to evaluate amount of semen collection. We are select two scabrood resistance A. cerana line (R and H). R line be used for rearing the Queen. Drone was reared in H line colony. The RH hybrid were not infected sacbrood virus even spread sacbrood virus (2×106). RH colonies have very excellent hygienic behavior, brood, and sacbrood disease resistance activity.

Most traditional genome sequencing projects involving infectious viruses include culturing and purification of the virus. This can present difficulties as an analysis of multiple populations from multiple locations may be required to acquire sufficient amount of high-quality DNA for sequence analysis. The electrophoretic method provides a strategy whereby the genomic DNA sequences of the Korean isolate of Pieris rapae granulovirus (PiraGV-K) were analyzed by purifying it from host DNA by pulsed-field gel electrophoresis, thus simplifying sampling and labor time. The genomic DNA of infected P. rapae was embedded in agarose plugs, digested with a restriction nuclease and methylase, and pulsed-field gel electrophoresis (PFGE) was used to separate PiraGV-K DNA from the DNA of P. rapae, followed by mapping of fosmid clones of the separated viral DNA. The double-stranded circular genome of PiraGV-K encodes 120 open reading frames (ORFs), covering 92% of the sequenced genome. BLAST and ORF arrangement showed the presence of 78 homologs to other genes in the database. The mean overall amino acid identity of PiraGV-K ORFs was highest with the Chinese isolate of PiraGV (~99%), followed up with Choristoneura occidentalis ORFs at 58%. PiraGV-K ORFs were grouped, according to function, into 10 genes involved in transcription, 11 involved in replication, 25 structural protein genes, and 15 auxiliary genes. Genes for Chitinase (ORF 10) and cathepsin (ORF11), involved in the liquefaction of the host, were found in the genome. The recovery of PiraGV-K DNA genome by pulse-field electrophoretic separation from host genomic DNA had several advantages, compared with its isolation from particles harvested as virions or inclusions from the P. rapae host. We have sequenced and analyzed the 108,658 bp PiraGV-K genome purified by the pulsed field electrophoretic method. The method appears to be applicable to the analysis of genomes of large viruses. The chitinase, identified by PiraGV-K genome sequence, was functionally characterized by quantitative PCR, Western blot analysis, immunohistochemistry and transmission electron microscopy.

“Onnuri” is a new orchardgrass(Dactylis glomerata L.) variety developed by the National Institue of Animal Science (NIAS) in 2011. To develope the new variety of orchardgrass, 5 superior clones were selected and polycrossed for seed production. Agronomic growth characteristics and forage production of “Onnuri” were examined at Cheonan from 2009 to 2011, and regional trials were conducted in Cheonan, Pyungchang Jinzu and Jeju from 2009 to 2011, respectively. “Onnuri” showed medium type growth habit in fall and spring and medium in length of flag leaf and long upper internode. Plant height of “Onnuri” was more than 10cm that of standard variety, “Amba” and heading date was 5 days earlyer than 16th May compared to Amba. Characteristics such as waterlogging, disease resistance of “Onnuri” were stronger or better than those of Amba, specially “Onnuri” showed 18% higher dry matter yield (14,775kg/ha) compared to Amaba(12,523kg/ha). Nutritive value was appeared to be similar in both varieties.

Italian Ryegrass is a high productivity and feed value, and an upright grass that behaves like a biennial or short-lived perennial. It grows vigorously in winter and early spring. Italian ryegrass and a related species, perennial ryegrass, Lolium perenne, are the two common weedy ryegrassses. Italian ryegrass and perennial ryegrass can hybridize, resulting in offspring that are difficult to identify as either species. Ryegrasses are cultivated for turf and forage. Sometimes Italian ryegrass is grown as cover crop. It has the potential to produce high yields and, with proper management, can be high quality with good animal performance. To develop of a high quality, productivity and early variety, 20 varieties examined growth and yield characteristics. The heading date of Green farm with high cold tolerance was on 28 April. Most of Introduced varieties except Grazer have mid and late heading date.

The main nutritional problem of sorghumxsudangrass hybrid (Sorghum bicolorxSorghum sudanese) silage is low quality and palatability. This experiment was conducted to evaluate whether organic com grain and crushed rice addition of sorghumxsudangrass hybrid silage increases forage quality of the silage. The sorghumxsudangrass hybrid silages with added com grain and crushed rice were similar to conventional corn silage in moisture content. However organic sorghumxsudangrass hybrid silage had low pH values. Silage added with gain and byproduct had higher crude ash, acid detergent fiber (ADF) and neutral detergent fiber (NDF) contents than control corn silages, while its non-fiber carbohydrate (NFC) and total digestible nutrients (TDN) showed the opposite results. Lactic acid, butyric acid and lactic percentage oftotal organic acid (UT) of sorghumxsudangrass hybrid silages were higher than those of com silage, but acetic acid was higher than control. In vitro dry matter digestibi/ity (IVDMD) of com silage was higher than other sorghum silages. Feed intake of sorghumxsudangrass hybrid silage added with crushed rice was highest among silages. Therefore, these data indicate that crushed rice and com grain added sorghumxsudangrass hybrid silage could be recommended as the most effective treatment for increasing silage quality and palatability.

A new black seed coat soybean variety, “Socheong” was developed at the Yeongnam Agricultural Research Institute (YARI) in 2006. The goal to breed the black seed coat soybean is to develop the cultivar with high yield, lodging tolerance, resistant to disease such as soybean mosaic virus (SMV), and bacterial pustule and seed size. Socheong was selected from the cross between Milyang 78, which was late maturing, susceptible to lodging and SMV and with large seed size and green cotyledon, and Peking which was tolerant to lodging and with small seed size. The preliminary, advanced and regional yield trials for evaluation and selection of this variety were carried out from 2002 to 2006. It has determinate growth habit, white flower, brown pubescence, brown pod color, black seed coat, green cotyledon, elongated flattened seed shape, oval leaf shape and small seed size (15.7 grams per 100 seeds), and it was 3 days later in maturity than the check cultivar Cheongjakong. Socheong was higher, in the seed quality of sucrose and total sugar contents (6.8 and 8.2%) and isoflavone contents (1,754 ㎍/g) than the check cultivar. Futhermore, it has good characteristics for mechanical harvest, such as lodging tolerance, pod shattering and stem diameter. It also has been identified to have resistance to soybean mosaic virus symptom which was the troublesome soybean diseases. The average yield of Socheong was 2.21 ton per hectare in the regional yield trials carried out in four locations of Korea among seven locations from 2004 to 2006, which was 5 percent lower than the check cultivar Cheongjakong.

A new black seed coat soybean cultivar, “Heugmi” was developed at the Yeongnam Agricultural Research Institute (YARI) in 2006. The goal to breed the black seed coat soybean is to develop the cultivar with high yield, lodging tolerance, resistant to disease such as soybean mosaic virus (SMV), and bacterial pustule and seed size. Heugmi was selected from the cross between Milyang 78, which was late maturing, susceptible to lodging and SMV and with large seed size and green cotyledon, and Milyang 68, which was middle maturing, resistant to lodging and SMV and with middle seed size and yellow cotyledon. The preliminary, advanced and regional yield trials for evaluation and selection of this cultivar were carried out from 2001 to 2006. It has determinate growth habit, purple flower, brown pubescence, black pod color, black seed coat, green cotyledon, spherical seed shape, oval leaf shape and middle seed size (24.8 grams per 100 seeds), and it was 2 days earlier in maturity than the check cultivar Cheongjakong. Heugmi was better in the seed quality of crude protein contents, sucrose and total sugar contents than the check cultivar. It also has been identified to have resistance to SMV which was the troublesome soybean diseases. The average yield of Heugmi was 2.53 ton per hectare in the regional yield trials carried out in seven locations of Korea from 2004 to 2006, which was 8 percent higher than the check cultivar Cheongjakong.