| Bottle gourd has been used widely for grafting of curcurbitaceae crops like watermelon and muskmelon. Using bottle gourd as stocks can overcome soil-borne disease, avoid continuous cropping obstacles, release the harm of soil secondly salinization of agricultural facilities, and enhance crop yield. By now, the studies of resistance on watermelon Fusarium wilt. and root-knot nematode, the genetic diversity, and stocks selection of watermelon grafting seedlings under specific weather conditions have been few. This research, which is aimed at selecting root-stocks with strong resistance on watermelon Fusarium wilt. and root-knot nematode and higher grafting compatibility and symbiosis, and providing instructions to use stocks with phenotypic divergence of disease resistance as breeding materials, was studied by observing agronomic characters of 32 bottle gourd stocks which were collected from Japan and China, inoculating 2 diseases to them, and analyzing heterosis of disease resistance of these stocks by complete diallel cross. The main results were showed as following.1. Analyzing 12 seedling characters and 5 fruit characters of 32 bottle gourd stocks, the ones which coefficient variation were low were seedlings characters like hypocotyl thickness (12.02%), and cotyledon stenter (17.10%). And the higher ones were fruit characters like per fruit weight (39.94%) and stem diameter (32.88%). Using PCA to 12 seedling characters, the result showed that cotyledon stenter, cotyledon length, overground fresh weight, overground dry weight, underground dry weight, stem diameter and hypocotyl length were main indexes to measure growth condition of bottle gourd seedlings.2. By cluster analysis, the stocks were divided into 3 groups. Group I were ones whose cotyledon length and stenter, stem diameter, and hypocotyl length were in the middle. Their overground fresh weight and underground dry weight were higher. Seedlings of this group grew well and had better foundation for grafting. Group II were ones whose hypocotyl length and cotyledon length were higher. This group showed excessive growth and was suit for grafting at young age. Group III were ones whose hypocotyl length was shorter.3. The watermelon Fusarium wilt, inoculation study showed that, as time went by, the resistance of bottle gourd stocks decreased gradually. After been inflected for 35d,6 of them (H04, H05, H07, H10, H12, H13) had higher resistance on watermelon Fusarium wilt., accounting for 18.75%. 7 of 46 hybridized combination had higher resistance of watermelon Fusarium wilt., showing stronger heterosis.2 of cross combination (H05×H04, H10×H04) which used H04 as male parent had mid-parent heterosis, over high-parent heterosis, over-standard heterosis, and 3 kinds of over-low parent heterosis. H10xH04 had the strongest mid-parent heterosis and over high-parent heterosis, which was-65.60%. H05×H04 had strongest over-standard heterosis, which was-32.05%.4. The root-knot nematode inoculation study showed that the overground dry and fresh weight, relative underground dry weight, relative root superficial area, relative stem length, and ovum amount per root fresh weight could value the root-knot nematode resistance of stocks comprehensively. By subordinative function value, the order of resistance to root-knot nematode of gourd stocks homozygous inbred lines from strong to weak was H04> H07> H05> H12> H13> H10; and of hybridized combination was H05×H13> H10×H13> H10×H04> H05×H04> H04×H05> H12×H05> H05×H12. The gourd stocks was divided into three groups named low resistance, sensitive and high sensitive. Totally, H04, H05, H07, H12, and H13 grew well and had stronger resistance on watermelon Fusarium wilt. and root-knot nematode, the cross combination of them had heterosis. They could be parents for watermelon stock breeding. |
PDF Full Text Request