헝가리 고추의 원예화를 위한 유전자원 특성평가
Evaluation of Genetic Resource Traits for the Development into a Horticultural Item of Hungarian ‘Hot Pepper Varieties’
Article information
Abstract
This study was conducted to evaluate 35 units of genetic resources collected from Hungary in 1999, and identify their horticultural traits and select useful resources. A comparison with ‘Geumdang’ and ‘Superbigarim’, the two varieties of Korean origin now being marketed indicated that the durations of time involved in flowering were largely similar to each other, and that the stem length of the Korean varieties averaged 163 cm, comparing with that of Hungarian varieties that averaged 133 cm. As for the fruit shape, the sweet banana type which was similar to the Korean counterpart accounted for 83%, ranking a top, followed by smaller varieties of which the cherry type accounted for 14% of the total. The hungarian varieties averaged 34.7 g in weight, a level significantly heavier than the Korean counterparts that averaged 25 g. As regards the ASTA value, 9 resources registered 100 or over, and as regards sugar contents, 4 resources reached 15% or over. As for capsaicinoid contents, 69% of the resources reached 10 mg% or lower, and 17% reached 10~40 mg%, followed by the group of 49 mg% or over that accounted for 14%. As a rule, the resources sampled for the current study were relatively less hot in taste.
I. Introduction
A crop of Solanaceae species, the hot pepper (Capsicum spp) was introduced into Korea about 400 years ago. It is regarded as an important seasoning vegetable (Pae et al., 2005; Yoon et al., 2004), and the major species are C. annuum (Yoon et al., 2004). Having a polyploid genome of a suitable size and featuring such excellent traits as hot taste, attractive fruit coloration and shapes, nutrients and so forth, the hot pepper has been known as the most widely used species in the food industry in Korea (Govindarajan and Sathyanarayana, 1991). The area under hot pepper cultivation reached 45,459 ha in 2012 or about 20.9% of the total area planted with vegetables. The total yearly production was estimated at 12,939 trillion won (National Statistics Portal: http://kosis.kr). This ranks the red pepper second to rice in terms of the total value produced, thus economically making it one of the most important crop of the country. Besides, the hot pepper varieties registered with National Board of Plant Seeds numbered 2,259, or 40% of the number of major vegetables including combined radish, cabbage, melon, water melon and red pepper. Such a wide range of varieties that have been developed is attributable mainly to the development of disease-resistant varieties. Recently, coloration along with hot and sweet tastes as well as productivity and morphological traits of the fruit are now considered to be important factors in evaluating traits of varieties and their quality. At the same time, consumer attention is being diversified from uses of dried and raw peppers to pepper as an ornamental plant, paving the way for generating a new source of income (Kwon et al., 2005). However, pepper varieties on the domestic market are similar in their visual and flavor traits, thus making it essential to collect a variety of world’s genetic resources and get at their traits that make them fit for samples from which to breed new varieties in view of various consumer preferences and functionality (Jeon et al., 2013).
Production of Hungarian hot peppers evaluated in Europe as superb in terms of taste and aroma reached 128,000 tons in raw pepper (FAO, 2011) and 26,000 tons in dried pepper. The total areas planted with hot pepper reaches 2,668 ha for raw pepper and 2,125 ha for dried pepper. Exports are now being diversified, centering around the European market. This study proposes to analyze horticultural traits, shape, resistance against diseases and functional ingredients of 35 items of Hungarian varieties sampled for the study that feature outstanding redness when processed as food, which average consumers prefer, and come up with basic data for the breeding of new varieties and developing them into plants for horticulture.
II. Materials and Methods
1. Evaluation of horticultural traits of hot pepper’s genetic resources
‘Geumdang’ and ‘Superbigarim’ as comparison varieties now being domestically marketed and genetic resources collected from Hungary were placed in Benlate T 500-fold fluid for sterilization during 30 minutes, and placed in a vessel of constant temperature at 30°C for three days, and sewen with 50 seeds each, 3 times repetitively in a plug tray. Two months later, after the seedlings were planted with 10 plants in a row, spaced 40 cm with the furrow 110 cm wide in the rain shelter greenhouse, horticultural traits were evaluated. The experiment was conducted based on the guidelines for survey on genetic resources. To verify resistance against disease, the number of the plants that contracted a disease per plant planted for each 35 genetic resources was identified, with a focus on natural occurrence of diseases.
2. Analysis of taste and color of hot pepper’s genetic resources
Hot peppers out of evaluation resources rated at 35 points were imported, heat-dried with their seeds removed. Rinds and placenta were ground by a pulverizer and passed through a 0.5 mm sieve. The pepper powder was analyzed for American Spice Trade Association (ASTA) coloration values and hot taste, and sugar contents were analyzed. Coloration ASTA was measured at 460 nm, using a spectrophotometer (HP-8452, USA) after 100 mL acetone was added to 0.1 g hot pepper specimens by modifying the method of Han (1995) and extracted for 16 hours. For capsicinoid contents, after 10 mL acetonitrile was added to 1 g powder specimen and mixed for 2 minutes, and 1 mL supernatant fluid was taken, 9 mL distilled water was added, and injected into sep-pak plus C18 cartridges (Waters short body), capsaicinoids were absorbed, and the fluid isolated by means of 4 mL acetonitrile was analyzed by means of HPLC (LC-900, Jasco). Sugar contents were analyzed after 100 mL distilled water was added, steam boiled at 80°C for 25 minutes at 40 rpm, and then the specimen was left alone at normal temperature for 4 hours. After it was refined by a 0.45μ m membrane filter, it was analyzed by HPLC (LC-900, Jasco).
III. Results and Discussion
1. Evaluation of horticultural traits of genetic resources
Results of evaluating horticultural traits of genetic resources show that 4 resources such as 12011038 were isolated and collected for seeds in a mixture as shown in Table 1. However, the 31 resources that remained turned out uniform in plant shape. As for the duration of the period required for flowering, ‘Geumdang’ and ‘Superbigarim’ native to Korea flowered after 89 days and 92 days, respectively, while the Hungarian red pepper varieties flowered after 92 to 103 days showing that the Hungarian varieties flowered later than Korean varieties. The stem height of the Hungarian hot peppers averaged 133 cm, as much as 30 cm shorter than those of Korean origin. This makes the Hungarian resources the right kind suited to rain shelter green houses with their cultivating area being steadily expanded. Hot pepper varieties now on the local market are largely disease-resistant varieties, featuring superb quantity productivity. As for disease incidence of resources collected from Hungary in the seedling field, 66% of the resources was free from contagious diseases, while 5 resources including 12011030 resources contracted diseases and showed their cultivation traits were unsuitable for the purpose of developing resources. However, since this is the outcome of having surveyed disease incidence with a focus on contraction in the seedling field, further detailed studies are needed for verification of resistance against diseases by conducting seedling test or molecular marker (Lee et al., 2012; Lee et al., 2011). 83% of the fruits collected from Hungary were of the sweet banana type, which is now being marketed in Korea, 5 resources of the cherry type were also observed, and 12011056 resource took on an emerald giant fruit shape (Table 2). The fruit length of the sweet banana type was 13.5 cm long similar to the kind on the local market but the fruit diameter of 3.0 cm was showed largely big in fruit size than 2.2 cm, the variety now on the local market. The raw fruit weight averaged 34.7 g, a figure higher than ‘Geumdang’ that weighs 23.4 g and ‘Superbigarim’ that weighs 27.5 g. The thickness of the flesh averaged 3.0 mm, a little thicker than the comparison variety. Though the shape and state of the fruit were generally similar to the varieties cultivated in Korea. But it was thought that the fact that the fruit diameter was generally wider and fleshly parts were thicker and heavier makes it a suitable model from which to develop a new variety so that it may adapt to local environment. Of them all, the 12011035 resource, which looks much like a sweet banana in shape, features a superior shape, fruitbearing, and extremely short fruit lengths, compared with those on the domestic market, making it ideal as a breeding stock plant (Fig. 1). Hot pepper is also finding its way into the ornamental pot plant market. Hot peppers planted in a flower pot are lovely to look at, making it an ideal item as a pot plant, too. Furthermore, hot pepper fruits last longer than ordinary flowering plants, enabling onlookers to enjoy them for long, another favorable feature unique to hot pepper. Of the resources collected from Hungary, the two resources 12011055 and 12011059 are lovely with their cherry-like fruits and short in stem length, making it an excellent ornamental horticulture item.
2. Evaluation and analysis of taste and color
When pigment contents have been expressed in ASTA values, hot peppers of Hungarian origin averaged 88, similar to ‘Geumdang’ now on the local market. However, 9 resources exceeded 100, of which the resource 12011035 reached 172 (Table 3), making it an ideal item for breeding for domestic cultivation. Taste of a hot pepper is determined by contents of combined capsaicin and sugar (Jung et al., 2006). The sugar content of the Hungarian hot pepper averaged 11%, a level higher than that of ‘Geumdang’ that averaged 8.2%, and lower than ‘Superbigarim’ that averaged 12.4%. Contents of capsaicinoids make the red pepper taste hot. The bulk of the red peppers collected from Hungary lacked hot taste, with an average capsaicinoid content pointing to 13 mg%, a level higher than that of the comparison variety that reached 4.9 mg% and 3.6 mg%. Four resources such as 12011042 exceeded 40 mg% in the level of hot taste. Of them all, 12011053 and 12011055 resources amounted to 80.5 mg% and 93.7 mg%, a level extremely hot. At this time when changes and diversification in the dietary style today demand a variety of hot tastes in the case of raw hot pepper fruits and powdered hot pepper (Jung et al., 2006), imported resources which are not hot at all on the one hand and hot varieties such as 12011053 and 12011055 with a capsaicinoid content rated at 80 mg% or over on the other could ideally be combined to adjust the level of hot tastes. Genetic resources of hot peppers serve the purpose of collecting new resources every year, breed new varieties, study their traits and select resources that will best serve as breeding domestic stock plants. The results of evaluating horticultural traits of the resources collected from Hungary in 1999 show that most of them were found to be suitable for domestic cultivation and management in rain shelter green houses, with their relatively low stem length. The line in 12011035 in particular features high pigment levels, bigger in fruit size as well as shorter in stem lengths, making it an ideal variety to breed as a high pigment plant for cultivation in domestic rain shelter green houses. However, it is recommended that further efforts be made to breed superior varieties featuring excellent coloration and tastes in view of changing trends of general consumer’s preferences (Hwang, 2008).
IV. 적요
본 연구는 1999년 헝가리에서 수집한 고추 유전자원 35점을 평 가하여 원예적 형질을 조사하고 유용한 자원을 선발하고자 실시하 였다. 한국시판 대비 품종 ‘금당’과 ‘슈퍼비가림’과 비교했을 때 개 화소요일은 거의 유사하였으며, 초장은 한국 품종이 평균 163cm 이었으나 헝가리 자원은 133cm로 작게 조사되었다. 과형은 한국 품종과 유사한 sweet banana형이 83%로 가장 많았고, 소형은 cherry형이 14%였다. 과중은 대체로 한국 품종 25g에 비해 무거워 평균 34.7g이었다. ASTA 값은 100이상이 9자원이었으며, 당함 량은 15% 이상이 4자원이었다. Capsaicinoids 함량은 10mg% 이 하인 자원이 69%, 10~40mg%가 17%, 40mg% 이상은 14%로 대 부분 매운맛 성분이 적은 자원이었다.