본 연구는 충청북도농업기술원 대추연구소에서 보유 중인 대추 유전자원 중 형태적 다형성을 나타내는 ‘일본’과 주요 대추 유전자원의 형태형질을 조사하고, 대추 육종 소재로서 ‘일본’의 가능성을 확인하기 위해 수행되었다. ‘일본’은 주요 대추 유전 자원과 비교하여 엽과 과실의 크기가 뚜렷하게 작고 당도가 낮았다. 하지만 과실에 폴리페놀 함량이 가장 높았으며, 항산화 능력 또한 가장 높았다. 또한 ‘일본’은 종자형성능이 가장 높았다. 대추 유전자원들의 형태형질을 이용하여 분석한 결과, 지리적 기원에 따라 유전자원들이 분류되었다. 특히 ‘일본’은 한국 및 중국 유전자원들과 명확히 구분되었다. 따라서 종자형성능이 우수하고 기능성 성분이 높은 ‘일본’은 추후 대추 유전연구 및 교배육종을 통한 품종 육성에 유용하게 이용될 수 있을 것으로 생각된다.

사과 ‘후지’/M.9 포트묘목 개발을 위해 질소시비농도에 따른 생장특성을 조사하고, 포트 우량묘목 생산에 적합한 질소시비 농도와 잎의 무기영양성분 함량 및 토양 화학성의 안정성을 확인하였다. 질소시비농도가 높아질수록 묘목의 생장은 증가되 었고, 특히 16 mM 처리가 수체 생장에 가장 좋았으며, 우량묘목 판단기준에 부합하였다. 32 mM 이상의 고농도는 오히려 생장 을 감소시켰다. 잎의 무기영양성분 함량은 8, 16 mM 처리구에서 기존 사과과원의 적정수준보다 높았고, 이러한 무기영양성분은 정식 후 수체 생장에 도움이 될 것으로 생각되었다. 토양 화학성 또한 8, 16 mM 처리구에서 안정적이었다. 따라서 수체 생육, 잎의 무기영양성분, 포트 내 토양화학성을 고려한 결과, 사과 ‘후지’/M.9 우량 포트묘목 생산을 위한 적정 질소시비량은 16 mM로 판단되었다.

The study was performed to investigate basic tree growth and fruit characteristics of ‘Nero’ black chokeberry (Aronia melanocarpa) depending on the different cultivation regions and altitudes in 2014, 2015. Tree growth and change of developmental stages of ‘Nero’ were similar regardless of meteorological environment of the four cultivation regions (Danyang, Okcheon, Yeongdong, and Geumsan) in 2014. Fruit characteristics of ‘Nero’ were significant differences in berry weight and anthocyanin content among the four orchards due to difference in cultivation techniques and relatively wide daily temperature range just before harvest, respectively. Tree growth and change of developmental stages of ‘Nero’ grown at the two orchards with different altitudes appeared to be similar during the successive years 2014 and 2015. Soluble solids content of the berries cultivated at low altitude (117 m) was higher than at high altitude (342 m). Acidity showed an inverse pattern with soluble solids content. Anthocyanin content increased progressively until at the middle of August, 2014-15 and then it decreased. Our results showed that black chokeberry is a species adaptive to the domestic environment as there were no differences in tree growth and change of developmental stages of ‘Nero’. Considering fruit quality of black chokeberry such as soluble solids content, acidity, and anthocyanin content, our results suggest that optimal harvest period of black chokeberry ‘Nero’ is August 8 to 19.

Effects of different soil water conditions on fruit characteristics were investigated in 5-year-old ‘Nero’ black chokeberry trees (Aronia melanocarpa). Three kinds of drought stresses, including low water deficit, severe water deficit, and very severe water deficit, due to decline of soil water decreased the fruit quality of weight of 10 berries, soluble solid content, and anthocyanin, compared with the control (consistent water supply) during the harvest period. After longer drought stress, supply of soil water could induce berry cracking because cell size of epidermis of fruits contracted, whereas cell size of sub-epidermis and flesh expanded. Thus periodic water supply using water supply facility is needed for yield and quality of ‘Nero’ black chokeberry fruits.

The objective of the study was to identify 52 Asian pear accessions, two primary pear species, and one reference pear Asian pear with 12 microsatellite markers to maintain pear germplasm collection. The number of alleles of 12 microsatellites detected ranged from eight at CH03d12 to 18 at CH01f07. Gene diversity ranged from 0.7053 at CH01d08 to 0.9224 at CH01f07. The lowest value of PIC was 0.6600 at CH01d08 and the highest was 0.9171 at CH01f07. A group consisting of ‘Ooharabeni,’ ‘Bartlett,’ and P. calleryana was out-grouped and served as a reference to determine the relationship among Asian pear accessions. Except for the out-group, 50 Asian pears were segregated into two groups. Group I was divided in two small groups. Each small group was characterized by P. bretschneideri and P. ussuriensis, respectively. Group II was characterized as P. pyrifolia, and the group was divided in four small groups. The eigenvalue, difference, proportion, and cumulative of six principal components based on PCA to 12 microsatellite. The eigenvalue of the first principal components was 5.5850. The proportion of the first principal component was 0.9308. The cumulative value of the first two principal components was 0.9801. Consequently, nearly all of the results were elucidated by the two principal components. The results from analysis of the standard set of microsatellites in this study may be used as basic materials for the management of Asian pear germplasm collections, and the data might be useful in the development of a core collection.

Proline has been shown to accumulate in plant under various type of stresses. In our previous study, changes in cold hardiness and proline content showed contrasting patterns during a constant deacclimation. This study was performed to investigate the proline accumulation and related gene expression in response to repeated deacclimation and reacclimation in peach cultivar ‘Daewol’. Proline content was analyzed using the ninhydrin method and related gene expressions were examined using quantitative real-time RT-PCR. Proline contents of ‘Daewol’ increased during the repeated deacclimation treatments. Interestingly, during the twice deacclimation, expressions of P5CS (Δ1-pyrroline-5-carboxylatesynthase) constantly decreased, whereas expressions of P5CR (Δ1-pyrroline-5-carboxylatereductase) increased. Expressions of OAT (ornithine-δ-aminotransferase) indicated up- and down- pattern in response to repeated deacclimation and reacclimation. Our results indicated that proline responds positively to higher temperature in the shoots of peach cultivar ‘Daewol’ and expressions of both P5CS and P5CR genes could show contrasting patterns during the deacclimation. Moreover, our results suggest that ornithine pathway could serve as an alternative pathway in proline synthesis process during deacclimation in peach.

Proline (Pro) accumulation is a common physiological reaction in response to abiotic stresses in many plants. Accumulation of Pro is believed to play the important role in protecting cellular components from dehydrating effects due to such stresses. The study was performed to investigate the relationship between cold hardiness and Pro content or expression of related genes in peach cultivars during a constant experimental deacclimation. Changes in cold hardiness were determined using electrolyte leakage method in the shoots of 10 peach cultivars (Prunus persica ‘Aikawanakajima’, ‘Chiyomaru’, ‘Daewol’, ‘Janghowon Hwangdo’, ‘Kiraranokiwami’, ‘Mihong’, ‘Misshong’, ‘Soomee’, ‘Suhong’, and ‘Sun Gold’). Pro content was analyzed using the ninhydrin method and related gene expressions were examined using quantitative real-time RT-PCR. While cold hardiness of 10 peach cultivars decreased, Pro contents of those increased during the deacclimation. Notably, at the same time, expression of P5CS (Δ1-pyrroline-5-carboxylatesynthase) decreased in 10 peach cultivars, whereas expressions of P5CR (Δ1-pyrroline-5-carboxylatereductase) and OAT (ornithine-δ-aminotransferase) increased. Our results demonstrate that Pro responds positively to higher temperature in the shoots of 10 peach cultivars and expression of both P5CS and P5CR genes could show contrasting patterns during the deacclimation. Furthermore, our results suggest that ornithine pathway, which has been suggested to be important during seedling development, could serve as an alternative pathway in Pro synthesis process during the deacclimation in peach.

In this study, we sought to identify primary pears species and Korean native pears, without the use of morphological characteristics. In addition, this study was to establish pear DNA fingerprinting data for Korean native pears using 12 microsatellite markers, and to accurately classify a database for management of the Korean pear collection. Forty two pear accessions (7 primary pears, 5 Asian pears, 29 Korean pears, and 2 reference pears) were analyzed with twelve primers covering whole pear genome. In the present study, all pear accessions were successfully classified along with their pedigrees, and the distribution of primary pears was parallel to those of the previous taxonomic results. Korean pears were divided into 3 groups. Group I was characterized by Pyrus calleryana, and included Korean pea pears. Group II was characterized by P. pyrifolia, and was classified into 2 small groups. The first small group comprised of ‘Najucheongbae’, ‘Sunchanggulimdolbae’, ‘Andongmookbae’, ‘Andongdangsilri’, and ‘Najucheongbae’ and was presumed to be cultivars of P. pyrifolia. The second small group consisted of ‘Cheongdangrori’ and ‘Pyeongchangsuhyangri’. These two accessions were assumed to be a hybrid of P. pyrifolia and the other cultivar. Group III was characterized by P. ussuriensis. ‘Goesanhwangbae’, ‘Andongcheongsilri’, ‘Gongjucheongsilri’, and ‘Yecheoncheongbae’ were assumed to be cultivars of P. ussuriensis. Contrary to ‘Ulreungdocheongbae A’, ‘Ulreungdocheongbae B’ was classified as belonging to the P. ussuriensis group. It is possible that this is a consequence of, P. ussuriensis genes being transferred into ‘Ulreungdocheongbae B’. The result of this research reaffirmed the efficiency of a standard set of microsatellite markers and provides data, which will be useful for developing a core collection of pears.