Establishment of Hybrid Breeding System in Sweet Pepper = Establishment of Hybrid Breeding System in Sweet Pepper

다국어 초록 (Multilingual Abstract)

Sweet pepper (Capsicum annum L.) is a warm season crop that belongs to the solanaceae family. Itis a fast emerging vegetable and cash crop in Korea where seeds are quite expensive and most of the growing cultivars are exotic. Seventy percent growing area is under Kangwon Do. The main objective of this study was to create and select new genotypes of sweet pepper equal or better than existing hybrid cultivars. Anther culture was performed in Kangwon National University, horticulture laboratory and rests of the field experiment were performed in Hwacheon area. The anthers of widely grown hybrid cultivars (Derby, Debora, Fiesta, Special, Bossanova, Minipaprika, Clarity, Kufrah, Boogie, and Phenelene) were used in anther culture, where cultivar Kufrah had the highest percentage of callus formation (69.8%) but the percentage of plant regeneration were higher in Phenlene (2.67%) followed by Bossanova (2.41%). Even though there is the effect of genotype of donor plants on the success of anther culture, plantlets could be developed from all of these genotypes. These anther culture derived three hundred fourteen plantlets were morphological and cytological characterized. Twenty five percent plantlets were haploid which had shorter height and internodes, smaller leaves, plant structure, flower buds, fruit and stomata size, weak and poor in vigor and mostly seedless fruits with high total soluble solid contents as compare to diploid plants. Three plants were found male sterile. To determine the ploidy level of the plants obtained from in vitro anther culture, chromosome counts in root tip squashes and flow-cytometery were used. Distinct differences in stomata length was also noticed between haploid and diploid plants. One hundred twenty three inbred lines which were collected from abroad, inside the country and developed in the past were characterized on vegetative parameter (plant height, number of nodes to first branch, nodal color, maturity), flower and fruit characteristics (days to flowering, fruit set, fruit shape, fruit color, stalk cavity, apex grove), and yield parameter (average weight of fruit, yield per plant, and number of seeds per fruit). Variation in vegetative, fruit, and yield characters was observed. Seventeen lines were recorded with higher TSS content (>10.0%) where SP133, and SP91 had TSS 11.8%, and 11.7%respectively. Four lines (SP48, C01541, KNU3002, and SP142) had thicker pericarp (>6.0 mm).With respect to their over all performance, SP8, SP20, SP21, SP41, SP91, SP115, SP124, SP142, SP143, and KNU1009 were selected as superior inbred lines for cultivation.This characterization will help to identify the variety and to maintain purity in future. Beside this it will provide the information to the breeders on the varietal improvement work. Thirty eight female lines and twenty nine male lines were crossed and collected hybrid seeds of one hundred thirty combinations. These hybrid lines were grown in Vinyl house condition on field soil from last week of April to October in 2007 and 2008. Training and pruning were done by keeping three stems per plant. Nutrient and water were supplied through drip irrigation. The effect of crossing between male and female parents to the expression of characteristics in F1showed that; when small and big sized fruiting plants are crossed, F1 plants beard medium sized fruits, between red and yellow color all red color, between orange and yellow all yellow colored fruits, between round and lamuyo fruits it became glamour shaped fruits. Most of the hybrid lines were evaluated in 2007 and 2008. Among the hybrid lines thirty lines showed superior performance. In 2007, only hybrid cultivars; special and President, were grown as a control whereas in 2008, eleven commercial hybrid cultivars (Derby, Debla, Fiero, Special, Cupra, Fiesta, Jirisan, Maserati, Boogie, Plenty, and President) were grown for comparison. On the basis of good shape, taste, thick pericarp, high total soluble solid content, yield, and heterosis, seven hybrid lines; KNU1017(SP27), 5AVS5(SP27), 5AVS8(SP48), 5AVS7(SP45), 5AVS8(SP45), SP27(SP25) and SP12(SP38) were found superior, and selected for cultivation. These hybrid lines have heterosis on yield were 86%, 42%, 85%, 130%, 21%,67%, and 126%, respectively. Among them, 5AVS5(SP27) had yellow color fruit and the rest were red. In addition to this 5AVS1(SP43) had shown excellent performance as a minipaprika type containing high TSS, good taste, and conical shape. The other promising lines are KNU2006(SP14), KNU1006(SP14), KNU1009(SP27), KNU1015(SP32), 5AVS7(SP10), 5AVS8(SP32), 5AVS7(SP34), 5AVS7(SP27), 5AVS7(SP32), 5AVS8(SP10), 5AVS8(SP51), SP10(SP11), SP11(SP27), and KNU1015(SP27). The another experiment which was conducted to study whether priming with deep sea water results in enhancement of seed germination and to identify the optimum concentration of the priming solution, and duration of priming on sweet pepper (Cv. California wonder). Seeds were primed with five various concentrations (5%, 10%, 15%, 20% and 30%) for deep sea water for 48, 24, and 12 hours at 25℃. Priming in deep sea water (DSW) improved the early and final germination percentage, mean germination rate, emergence percentage and root and shoot length, compared with plain water, KNO3 and without priming treatments. 24 hours priming with 5 percentage DSW significantly improved the early germination percentage and radical length. It has also improved the mean germination and emergence days and early emergence percentage, compared with KNO3 and control. Hence the best seed priming treatment is 24 hours with 5 percentage DSW. Likewise in the study on the effect of deep sea water on root pruning of sweet pepper seedlings was done to minimize the excessive growth and root mat formation in Sweet pepper (Capsicum annuum L.) seedlings. Seeds were sown in plastic plug tray coated with 0%, 1%, 3%, 5%, 7%, 10% and 15% NaCl (w/v) and compared with control. Plants growth rate; shoot and root; length, fresh, and dry weight, and root structure were observed in seedling stage on plastic plug trays on 28, 35, and 42 days after sowing (DAS) respectively. Then same observation were recorded 35 DAT (days after transplanting). Results showed that NaCl coating had significantly minimized the excessive growth rate and root mat formation. Seedlings from the treatment produced more fibrous roots. Even though before transplanting, seedlings without treated were taller, longer root length, significantly higher fresh and dry weight of shoot and root but after transplanting, seedlings from NaCl coated trays showed better performance; taller plant, longer root, higher fresh and dry weight of shoot and root where 7% NaCl treatment gave the superior performance among the treatments and control. The optimum concentration of NaCl for coating plug tray appeared at 7% (w/v) to minimize root mat formation and to make appropriate growth.