한작지(Korean J. Crop Sci.), 55(1): 47~57(2010) Agronomic Characteristics of Squash Germplasm with a low viability in National Agrobiodiversity Center, Korea Jeong-Soon Kim*, Young-Wang Na*, Woo-Moon Lee**, Jae-Gyun Gwag*, Chung-Kon Kim*, and Chang-Ki Shim*† *National Agrobiodiversity Center, National Academy of Agricultural Science, Rural Development Administration, Suwon 441-100, Republic of Korea. **Vegetable Research Division, National Institute of Horticultural & Herbal Science, Rural Development Administration, Suwon 441-100, Republic of Korea. ABSTRACT More than 2,500 accessions of squash germplasm and C. ficifolia (Andres, 1990; Boyette et al., 1984; Nee, are preserved in the National Agrobidiversity Center of RDA, 1990; Zeven and Zhukovsky, 1975). Korea. We investigated the ecological and morphological The increased seeds would be available for genetic diversity characteristics on 100 accessions of the squash germplasms analysis. Currently, the Agrobidiversity Center of RDA possesses with a low viability. Two typical types of oriental squash 2,500 accessions of Squash germplasm in five specieis, C. (Cucurbita moschata) and western squash (Cucurbita maxima) are possessed 89 and 11 accessions, respectively. The origin maxima, C. maxima spp. maxima, C. mixta, C. moschata, of 100 accessions was divided into three groups, group I C. pepo, and C. pepo spp. pepo. (Korea landraces with 81 accessions), group II (Nepal with Many old world C. pepo have been reported as feral species 15 accessions) and group III (Russia, Uzbekistan, Laos, and in the US and Mexico, particularly in the coastal plain Mexico with each one accession). Seventy eight accessions from Florida to Texas and into northern Mexico. Worldwide, germinated at 27℃ in growth chamber. Days to first flowering there may be more squashes grown in home gardens than of the female and male flower ranged from 32 days to 67 days and 24 days to 55 days after planting, respectively. are grown commercially for sale in local or distant markets Vine length showed the largest variation ranging from 357.8 (Cowan and Smith, 1993; FAO, 1992, 2006; Grumet and cm to 1,465 cm, also the average length of ten stem node Gifford, 1998; Peirce, 1987; Smith et al., 1992). range has a variable ranges from 92 cm to 217.5 cm. All Diversity in C. pepo is rooted in the ancient widespread regenerated squash accessions have an only collided tendril distribution of free-living populations. Different morphological and have three to seven lateral shoots. The flattened globe- and physiological traits have evolved, including early fruit shaped squash is the most predominant and exhibited ordinarily abscission from the peduncle in response to riverine dispersal round shaped, ball shaped, long oblong-shaped, elongated shape, and pear shape. The average weight of fruit ranged (Decker and Wilson, 1986a, 1986b, 1987; Decker et al. 1993; from 1.33 kg to 7.95 kg. Sugar contents showed 5.4~12.6 Wilson, 1990; Wilson et al., 1992). Brix° without ripening period. At first, Cucurbita was domesticated; it was for their edible seed because the fruit was bitter and poisonous. Efforts Keywords : squash germplasm, Cucurbita moschata, Cucurbita are being made to breed C. pepo for “naked” seed coats maxima, morphological traits so the seed will be more palatable, and to domesticate C. foetidissima and other xerophytic species so they can be About 27 species of Cucurtbitaceae, Cucurbita spp. are grown in arid lands for their oil and protein-rich seed in distributed in the world, and of these species, only economically Mexico (Kirkpatrick and Wilson, 1988; Oris et al., 2002; important five species have been cultivated commercialy Thomas, 2000; Robinson and Whitaker, 1997). species, Cucurbita moschata, C. maxima, C. mixta, C. pepo, Squashes are generally divided into two groups. One group is the Summer Squash, which have soft skins and †Corresponding author: (Phone) +82-31-299-1878 (E-mail) [email protected] <Received November 28, 2009> are eaten when young. The other group is the Winter 47 48 한작지(KOREAN J. CROP SCI.), 55(1), 2010 Squash; these can be stored in the winter because they To be hardened off, the seedlings were exposed to outside have hard, protective shells. These are all warm-weather, temperatures and sunlight before planting. annual vines with large, lobed foliage and yellow blossoms. And Summer squash is Cucurbita pepo, but winter squash Transplanting may be C. pepo, C. moschata, C. mixta, or C. maxima Twenty-two days old and hardening off seedlings of 78 (Correll and Johnston, 1970; Wilson, 1990; Zhou, 1987). accessions were grown on black mulch with 4 replications Cucurbita is sometimes grown for ornamental purposes, each accession in the open-field of Chungnam Province at such as pumpkins and the ornamental gourd, C. pepo var. May 28, 2009. The soil was a loamy sand type. The chemical ovifera, or for the enormous fruit of C. maxima (Giant soil composions were checked before transplanting the pumpkin) grown for display purposes. In Latin American seedlings. countries, flowers, leaves and vine tips of Cucurbita are consumed, and mature fruit are used for livestock fodder Evaluation of agronomic traits or as containers (Decker and Wilson, 1986b; Paris and We carried out the regeneration and evaluation of agronomic Brown. 2005). traits according to the descriptors of RDA Genebank in The present study is based on comparative morphological Korea (RDA, 2004). And the morphological characteristics and anatomical investigation. It is intended that the result refer to the previous report by Chung et al. (1998) and the will provide the information about preserved Squash germplasm manual for Cucurbit seed production (McCormack, 2005). and variable genetic resources of squashes for the breeder To hand-pollinate the male and female flowers were tired and famer to breed a functional Squashes such as high up before flowering. Alternatively, we used a fine paintbrush sugar content, plant disease resistant and insect pest resistant to transfer the pollen from the stamens of male flower to Squash in Korea. the stigma of the female (McCormack, 2005). Observations on morphological characteristics, vegetative Materials and Methods and floral, were made on mature living plants grown in the open-field. Also, photographs were taken of relevant morphological Plant materials feature (Goldman, 2004). We selected and investigated to regenerate 100 accessions After transplanting, we observed the agronomic traits, from National Agrobiodiversity Center of Korea with Genebank days to first flowering of female and male flower (days), Management Program in 2009. One hundred accessions of color of flower, average length of vine (cm), number of lateral squash germplasms showed a lower viability and germination branch, average length of internodes per 10 nodes (cm), leaf rate in passport data. These accessions must be regenerated shape (angle, middle-angle, and round), average weight of without delay. We analyzed the profiles of tested squash ripen fruit (kg), fruit size, fruit shape, and sugar content germplasms about the origin, introduced countries, and (Brix°), every week from May 5 to Oct. 9. species. Results Germination All of tested seeds were in punched polyvinyl pack, and Genetic and Geographical Diversity of squash disinfected with 2% NaOCl for 2 hrs and washed with We analyzed one hundred accessions of squash germplsm distilled water three times, and placed on the moisture in two squash species, C. moschata and C. maxima according filter paper in the 11 × 2 cm of petri-dish at 27℃ for to the passport data of RDA genebank. One type is the 89 one-week. The germination rate of tested squash seeds accessions of oriental squash, C. moschata, and the other were checked at 7 days after sowing. Germinated seeds were type is the 11 accessions of western squash, C. maxima placed in 48 cell trays filled with artificial soil media in a (Table 1). The origins of 89 accessions were grouped in three: greenhouse, and then checked the emergence rate of seedling. group I (Korea landrace with 81 accessions), group II (Nepal Agronomic Characteristics of Squash Germplasms 49 with 15 accessions) and group III ( Russia, Uzbekistan, Laos, male were 47.9 (±11.1) days and 39.5 (±8.4) days, respectively and Mexico with each one accession) (Table 1). (Table 3). The average length of main vine was estimated from Seedlings Culture root crown to tip of plant at 110 days after squash seedling For germination, they were placed on wet filter paper in transplanting. The average length of main vine was 807.1 Petri dishes at 27℃ after disinfection of microbes. Only (±7.2) cm. And the average length of minimum and maximum fifteen (15%) of 100 accessions showed germination rate of main vine were 357.8 (±6.9) cm and 1465.0 (±12.9) cm, higher than 85% and also sixty-eight accessions have a respectively (Table 3). low germination rate lower than 55% after 7 days (Fig. 1). The average number of lateral branch of each plant distributed Among one hundred accessions, seedlings of seventy eight from 3 to 7. The number of lateral branch is 3 in forty- accession emerged at 22 days after sowing in the greenhouse. nine accessions. All of the accessions have a tendril with The field soil conditions were good for regeneration of same shape. And the average length of internodes per 10 squash germplasm in Chungnam Province (Table 2). nodes was estimated at 115 days after seedling transplanting. The average length of internodes per 10 nodes ranged from Quantitative traits of squash growth 92.0 (±2.5) cm to 217.5 (±6.5) cm (Table 3). Twenty-two days old seedlings of seventy-eight accessions We estimated the characteristics of matured fruit, fruit were transplanted with 4 replications at May 28, 2009. height (H), fruit diameter (D), fruit shape (H/D), fruit weight, The first plant of female flower opened at 32 days and and thickness of flesh.