Fusarium wilt caused by Fusarium oxysporum f. sp. lagenariae is a destructive disease in cultivation of watermelon worldwide. This study was carried out to screen resistant lines to Fusarium wilt and to confirm resistant level of F1 hybrids derived from resistant lines by seedling test in bottle gourd to develop watermelon root stock. Symtpoms of bottle gourd seedlings infected by Fusarium oxysporum f. sp. lagenariae were netted yellowing on the lowest leaves as the initial symptom and then progressed to shrinking of leaves and brown lesions just above the groundline and went to complete death. As a results of resistance screening by seedling test, four lines (71, 963385, BG710, IT210520) and two F1 hybrids (BG703 × FR79 and BG703 × PFR11) were selected for Fusarium wilt resistance. Four lines can be used as parental lines to produce F1 hybrid rootstock for watermelon. Genetic factors of resistance between parental lines and their F1 hybrids were not clear. It seems that several genes were involved or there was gene interaction. However, genetic analysis will be needed for clear confirmation of genetic aspects on disease resistance using their F2 population. Moreover, parental lines shoud be carefully selected in order to develop highly resistant F1 hybrids because resistance level of F1 hybrids vary according to the combination of parents. This study confirmed the possibility of developing high-resistant watermelon root stocks using bottle gourd.

Background : Panax ginseng the king of Oriental medicines, has enormous potential against many of the disease symptoms and ailments. Panax quinquefolius is an another important member of Panax family which has similar benefits and medicinal properties. Both the species contains ginsenosides a pharmacologically active component abundant in their roots. In an effort to establish the new ginseng cultivars with improved agronomical characters such as root shape, stress tolerant and higher ginsenoside contents, the reciprocal interspecific hybrids were generated Methods and Results : Four elite cultivars and two new lines of ginseng were chosen to produce interspecies reciprocal hybrids with P. quinquefolius, by pollen dusting on the emasculated flowers. Among the F1 populations, the reciprocal hybrids generated by using new line 0837 both as maternal and paternal parent showed better properties and hybrid vigor. They showed strong root phenotypes with many lateral and fine roots thus having 10% to 20% higher ginsenoside contents compared to the parental populations. Among the major ginsenosides, the pharmacologically active ginsenosides such as Re, Rb1, Rb2 and F1 were enriched and accounted for the 70% of the PPD ginsenosides in 0837/Pq and Pq/0837 crosses, displaying strong dominance. Conclusion : Thus, based on our result we could conclude that P. ginseng line 0837 is the superior variety compared to the already existing lines for performing the interspecific hybrids with promising outcome in their root quality and ginsenoside content.

Brassica rapa subspecies show morphological variability, containing vegetable types and oilseed types. The yellow sarson types(Brassica rapa ssp, tricolaris) have distinct morphology, yellow seeded and contain some lines with very unique character of tetralocular ovary. For genetic studies on tetralocular ovary related to high seed yields, we produced genetic segregation population with F2 and double haploid(DH) population. The yellow sarson LP8 (YS-033, CGN06835) with character of tetralocular ovary used as a maternal plant and crossed by LP21 of turnip rape type with bilocular ovary as paternal plant. We took on the microspore cultures on immature bud which is collected on sizing from 2mm to 3.2mm for DH population. The regenerations DH plants are analyzed by ploidy determination using flow cytrometer and selected on diploid plants. These regenerated DH and F2 plants are doing bud pollination and measuring the phenotype traits. Also, these populations will be used for identify of genetic locus relate to tetralocular ovary using genotyping by sequencing.

Sweet pepper inbred lines (KNU1003, KNU1006, KNU1007, KNU1009, KNU1015, KNU1017 and KNU2006) developed at Kangwon National University (KNU) through conventional means, inbred lines (5AVS1, 5AVS2, 5AVS3, 5AVS5, 5AVS7 and 5AVS8) collected at Rural Development Administration (RDA) and inbred lines (SP12, SP27 and SP14) derived from anther culture were used as female parents and anther culture derived homozygous lines (SP9, SP10, SP14, SP24, SP25, SP27, SP30, SP32, SP34, SP38, SP43, SP45 and SP51) were used as male parents to produce F1 hybrids. A total of 37 F1 hybrids were evaluated for fruit yield and quality characters in summer season, 2007. Variation in fruit number, fruit weight, fruit yield per plant and fruit volume was observed among the F1 hybrids. Superiority on yield over standard/commercial varieties were differed among F1 hybrids. Hybrid 5AVS8 x SP45 exhibited highest heterosis over Special (16.5%) and Fiesta (24.7%). Fruit quality characters (fruit length, fruit width, pericarp thickness, total soluble solid, fruit shape and fruit color) were varied among the F1 hybrids. Fruit number, fruit weight and fruit volume per plant were correlated with fruit yield. Based on the standard heterosis expressed by the hybrids and quality characters evaluation, KNU1017 x SP27, 5AVS1 x SP43, 5AVS5 x SP27, 5AVS8 x SP45, SP12 x SP38 and SP27 x SP25 hybrids were found to be superior over commercial cultivars and are selected. Inbred lines of these hybrid combinations can be used to produce F1 hybrid seed for commercial production.

The aim of this project was to produce pure seed which F₁ hybrids were very excellent in yield components with hybrid vigour. The work was carried out to produce the seeds with maintenance of purity in an isolated P.E. film house, to investigat

The purpose of this study was to investigate the magnitude of commercial heterosis for seed yields in oilseed rape to determine the potential advantage of hybrids, especially to observe morphological charactes which may influence seed yields. Field tests