Earticle

The distribution of fruit characteristics of hybrid seedlings in cross combination of ‘Ehimekashi28gou’ was analyzed as data for citrus breeding. The larger fruit weight of male parent was, that of seedlings was large. The sugar content of the seedlings was lower than that of the male parent when using male parents with high sugar content. When male parents with low sugar content were used, the sugar content of the seedlings was improved than that of the male parent varieties. The acid content showed different characteristics depending on the male parents, and the use of ‘Seminole’ as male parent was highly likely to produce seedlings with high acid content. The peel color was different depending on the male parents. The proportion of seedlings with sugar content of 13 °Bx or more and acidity 1% or less was 0～9%, which was high in ‘Kanpei’ and ‘Setomi’, but not in ‘Natsumi’. In the case of sugar content of 10 °Bx or more and sugar acid ratio of 13 or more, was 0～32.1% higher than that of sugar content of 13 °Bx or more and an acidity of 1% or less. In summary, in the case of using ‘Ehimekashi28gou’ as the female parent, it was good to use male parents with a large fruit in order to obtain seedlings with a large fruit. And it would be advantageous to use male parents with high sugar content and low acidity in order to obtain seedlings with high sugar content and low acidity. Among the six combinations, the combination of ‘Ehimekashi28gou’ × ’Kanpei’ and ‘Ehimekashi28gou’ × ’Page’ was a good combination for high-quality production.

In order to evaluate the value of female parents in citrus cross breeding, the fruit characteristics of 1,864 seedlings in 19 combinations were analyzed. Target trait A was set to have a pulp rate of 80% or more, a sugar content of 13% or more, an acid content of 1% or less, no puffiness, easy peeling, and a=30 or more of the skin color. Target trait B was set to have a sugar content of 12 °Bx or more and a sugar acid ratio of 13 or more instead of sugar and acid content of target trait A. The rate of incidences satisfying the target trait A was 0.04～0.35%, the highest in the ‘Ehimekashi28gou’ combination, and the lowest in the ‘Harehime’ combination. The rate of incidences satisfying the target trait B was 0.07～0.84%, and also, it was the highest in the ‘Ehimekashi28gou’ combination. Although it will need to be supplemented in the future, it could be concluded that at least 212～416 seedlings should be needed in order to obtain a high quality seedling, since the rate of occurrence of excellent species is about 0.24～ 0.47%.

When plants are exposed to low temperatures that do not freeze, they receive cold damage, which causes physiological damage, and eventually dies. Recently, the temperature in winter shows a tendency to decrease due to extremely low temperatures, and the cold due to a sudden drop in temperature lasts for several days. As the abnormal low temperature phenomenon (cold wave) causing damage occurs frequently in Jeju Island, it is required to select an appropriate temperature for selection of citrus stock varieties that are resistant to cold damage. The purpose of this study is to select citrus cultivars resistant to cold damage, and to investigate whether shoots are formed in vitro and their growth status in vitro for citrus cultivars mainly used as cultivars. About the shoot formation rate in vitro was investigated, For 13 varieties, in vitro growth status, electrical conductivity, and fatty acid content were investigated. As a result, in vitro shoot formation rate in the Volcano lemon variety showed the highest growth rate compared to other varieties with a shoot formation rate of about 80% or more until 12 hr at low temperature exposure time. I could confirm that. On the other hand, it can be confirmed that the mortality rate of P. trifoliata, which is known as a high-temperature cultivar, was low compared to other varieties when exposed for 24 hours. In addition, at -4℃ in the in vivo growth state, the other cultivars did not die except for some cultivars, but the leaves of most citrus fruits were observed to fall and die in the citrus fruits exposed to -7℃. In addition, at -4℃ in the in vivo growth state, the other cultivars did not die except for some cultivars, but the leaves of most citrus fruits were observed to fall and die in the citrus fruits exposed to -7℃. In addition, in an in vivo experiment, it was confirmed that both leaves and stems receive rapid cold damage when exposed to -5℃ at low temperatures. In addition, the content of saturated fatty acid was increased in general citrus cultivars other than exudate leaves when treated for 12 hours at -4℃. That is, it could be inferred that when the exposure time to low temperature is prolonged, necrosis occurs due to cell membrane destruction due to cold damage. Therefore, it is judged that the proper temperature and time for the selection of citrus stocks that are strong in the cold damage should be treated at -5℃ for 12 hours and irradiated.

식물은 동결되지 않는 저온에 노출되었을 때 생 리적인 장해를 주는 냉해를 받게 되어 결국에는 죽게 되는데, 최근 겨울철 기온은 극한 저온 현상 으로 온도가 감소하는 경향을 나타내고 있으며 갑 작스런 기온 하강에 따른 추위가 수일 동안 지속 되어 피해를 유발시키는 이상 저온 현상(한파)이 제주도에서도 빈번하게 발생함에 따라서 냉해에 저항성을 갖는 감귤 대목 품종 선발을 위한 적정 온도 선발이 요구되고 있다. 본 연구는 냉해에 저 항성을 갖는 감귤 대목 품종을 선발하기 위한 하 여 대목 품종으로 주로 활용되고 있는 감귤류 품 종들에 대한 In vitro상 신초 형성 여부와 In vitro 상 생육 상태를 조사하기 위하여 감귤류 8품종의 접수에 대해서 In vitro상 신초 형성율을 조사하였 고, 13품종들에 대해서는 In vitro상 생육 상태와 전기 전도도 및 지방산 함량 변화를 조사하였다. 그 결과 In vitro상 신초 형성율은 볼케머 레몬 품 종이 저온 노출 시간 12시까지는 약 80%이상의 신초 형성율로 다른 품종들에 비하여 최고의 생장율을 보였지만 24시간 노출되었을 때 모든 접수가 냉해로 인하여 고사되는 것을 확인 할 수 있었다. 반면 저온에 강한 대목품종으로 알려진 탱자는 신 초 형성율은 저조함을 보였으나 24시간 노출되었 을 때 다른 품종들에 비하여 고사율은 낮게 나타 남을 확인 할 수 있었다. 또한 In vivo상 생육상태 는 -4℃에서는 일부 품종을 제외한 나머지 품종들 은 고사가 발생되지 않았으나 -7℃에 노출한 감귤 류들은 대부분의 감귤류들의 잎이 낙과되고 고사 되는 것이 관찰되었다. 게다가, In vivo상 실험에서 -5℃에 저온 노출되었을 때 잎 과 줄기 모두 급격 하게 냉해를 받음을 확인되었다. 게다가 삼출엽이 아닌 일반 감귤 품종은 –4℃ 12시간 처리했을 때 포화지방산 함량이 증가하였다. 즉, 저온에 노출 시간이 길어지면 냉해로 인하여 세포막 파괴로 인 한 괴사가 발생한다는 것을 추측 할 수 있었다. 따 라서 동해에 강한 감귤류의 대목의 선발을 위한 적정 온도와 시간은 –5℃에서 12시간 처리하여 조사하는게 적당하다 판단된다.

The occurrence of Huanglongbing (HLB) had been surveyed in 18 citrus orchards at 6 distantly separated locations such as Jejusi, Jocheoneup, Aewoleup and Hangyengmiaen, Daejungeup and Andeokmiaen, Seogwiposi, and Namwoneup form April to October of 2019. Psyllid, a vector of HLB, had been monitored using two commercial traps every orchards twice a month and trapping insects were identified by optical or microscopical diagnosis. As a results, 6 sorts of psyllid were identified but Diaphorina citri which is the vector of HLB has not been found. On the other hand, diagnosis of the citrus leaves showing HLB similar symptom were carried out by using HLB specific primer set. As a result, there were no HLB infected leaves.

This study was conducted to find out the varieties that are highly industrially available through the evaluation of biological activity of 12 kinds of jeju native citrus fruits and to promote the value added of traditional citrus. The antioxidant effect of ethanol extracts of jeju native citrus was shown in order of C. leiocarpe > C. nippokoreana > C. aurantium > C. benikoji > C. sunki ≅ C. platymama ≅ C. junos ≅ C. tachibana ≅ C. grandis > C. tangerina > C. erythrosa > C. pseudogulgul . The antioxidant activity of the C. leiocarpe and the C. nippokoreana was the highest at 69 ∼74%, and the antioxidant activity of the C. aurantium and C. benikoji was about 50%, and the C. pseudogulgul, C. tangerina and C. erythrosa showed the lowest antioxidant activity at about 16∼19%. The whitening effect was relatively high in the C. leiocarpe, C. nippokoreana, C. benikoji, C. erythrosa and C. aurantium, and the wrinkle improvement effect was relatively high in the C. leiocarpe, C. aurantium and C. tangerina. In addition, anti-inflammatory activity was relatively high in C. nippokoreana, C. benikoji, C. tachibana. The results of this study suggest that the functional activities of the C. leiocarpe, C. nippokoreana, C. aurantium and C. benikoji in Jeju native citrus are higher than other varieties, which is considered to be highly industrially useful. In the future, more specific research on the industrial use of jeju native citrus is needed.

본 연구에서는 감마선 조사된 가온재배 ‘부지 화’의 저온저장 중 과실의 경도, 중량 감모, 품질, 과피상태 및 총 플라보로이드 함량변화를 조사했 다. 과실의 당도 및 비중의 감소는 없었으나, 과 실의 경도, 중량 감모량, 과즙의 총 플라보노이드 함량 및 산함량도 특히, 저온 저장 60일째에 무 처리 보다 낮았다. 그 저장 70일째는 감마선 처 리 과실에서 주름과 및 호반증이 발생했다. 이상 의 결과, ‘부지화’의 감마선 처리시 물리적 충격 이 과실의 품질과 신선도 저하에 관계가 있었다 는 것이 시사가 되었다.

This study investigated the changes of fruit firmness, weight loss, quality, peel state and total flavonoid content in gamma irradiated-‘Shianuhi’ mandarin hybrid cultivated in heating house during low temperature storage. There was no difference in total soluble solids (TSS) content and specific gravity, while fruit firmness, weight loss content of the fruits, the total flavonoid content and acidity content in juice extracted from gamma radiation treated fruits were especially lower than those of the control after 60 days of the low temperature storage. Creased fruit and rind-oil spot were also occurred in the treated fruits after 70 days of the storage. These results suggest that the gamma ray irradiation in the ‘Shianuhi’ be effected on quality and freshness lowering as physical impact at time of the treatment.

Citrus fruits are native to India, Myanmar, Peninsular Malaysia, Indochina, China, Korea, and Japan. The citrus cultivation in the world spreads from the tropics(from 40 degrees north latitude to 40 degrees south latitude) to temperate zones, reaching about 50 countries. Among the ingredients of citrus peel, turpentine, rutin, and hesperedin have various effects. As a result of investigating cases of domestic and foreign patents related to citrus fruits and analyzing patent trends, domestic and foreign patent applications have been decreasing rapidly since 2017, and are mainly counted in the order of food, cosmetics, and medical substances. The distribution by country was 65% in Japan, 21% in China, and 11% in Korea. Japan is specialized in medicines, cosmetics and related machinery, while Europe is concentrated in medicines and cosmetics. In the United States, it appears that plant patents dominate. The patent trend in the field of citrus utilization in Korea appears to be in the early stages of maturity passed the development stage in the transition analysis divided into development stage, maturation stage, reflux stage, and resurrection stage.