| Cucumber is an important vegetable crop in the world. Due to narrow genetic base of cucumbers, low polymorphism among cucumber cultivars, greatly limited the breeding process of cucumber. Using the specific germplasm resources of cucumber varieties is an effective way to variety improvement and germplasm innovation. Cucumis hytivus Chen and Kirkbride is the world’s only successful interspecific hybridization in cucumber, utilized it to cross with cucumber cultivars and created allotriploid cucumber which had high growth vigor and unique fruit flavor. So the allotriploid cucumber could be used as a new type of greenhouse cucumber. This study included the reciprocal crosses carried out between C. hytivus and C.sativus, and cross-compatibility evaluated in different cross combinations in order to provide the basic theoretical basis for broadened the cucumber genetic resources and solved the cucumber breeding problems.Storability is closely related to commodity quality. The water content of cucumber fruit is very high so that easily dehydrated aftef harvest, resulting in fruit softening and even rot, seriously impacted on the quality. Now the domestic cucumber cultivar is thin skin, poor storability and short shelf life. Ningyun No.3was the storability cucumber cultivar with long shelf life. It could regulate the production and sold balance, supply and demand of cucumber, activate the market, increase the income of growers.Based on the above background, carried out the research about the reciprocal hybridization and cross-compatibility analysis of C.hytivus and C.sativus and the storability characteristics of cucumber. The mian results were:1. Reciprocal hybridization between C.hytivus and C.sativusWhen C.hytivus as the female, the average fruit set percentage of cross combinations was47.18%, the seeds per fruit were14.61; while C.sativus as the female, the average fruit set percentage of crosse combinations was44.90%, the seeds per fruit were16.32. Given genotypes of cucumber cultivars, the cross combination between C.hytivus and the north China type cucumbers had much more fruit set percentage and seed number per fruit than other combinations, so these cross were conducive to creat allotriploid cucumber. Thousand kernel weight also reflected that the quality of hybrid seed was better when C.hytivus as the female. The result showed that the genotype of cucumber cultivars influenced the effect of hybridization.2. ITS sequence analysis of several Cucumis cropsITS sequences length (including5.8S) was618-640bp with GC content of58.7-64.5%in different Cucumis materials. In cucumber, the variable and the informative sites was105and20, respectively, accounting for22.01%and4.19%of total bases. Based on the ITS sequences information in Cucumis, C.hytivus had a closer genetic distance and a higher cross-compatibility with the cucumber cultivars from China. In molecular level to further verify the genotype of the cucumber cultivars influenced the hybrid effect.3. Physiological and biochemical characteristics of cucumber during StorageFruits of Ningyun No.3and Nankang No.l were used as the materials in storage from3days to13days after harvesting. The results indicated that during storage fruit firmness dropped by15.73%for Ningyun No.3and32.74%for NanKang No.1; fruit weight loss rate was2.49%for Ningyun No.3and6.17%for Nankang No.1; MDA content significantly increased by80.15%in Ningyun No.3and102.88%in Nankang No.1; upon storage for one week, the SOD activity of Ningyun No.3remained84.20%higher than Nankang No.1whereas the respiration rate was38.29%lower than Nankang No.l. With storage for longer time, most measurements reached significant difference the two cultivars. |
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