The Construction Of Cucumber Regeneration System And Selection Of Heat-Resistant Materials

Cucumber is one of the most important vegetables in the word. The selection of heat-resistant varieties is the most important priority as the global climate becoming warmer. The conventional breeding is an inefficient way in terms of the cucumber's narrow genetic range and the waste of manpower and resources. While the heat-resistant mutants in vitro can be operated directionally and efficiently under artificial high-temperature environment. This paper mainly studied the establishment of regeneration system and selection and identification of heat-resistant mutant. The results were as follows:1 The establishment of regeneration systemCucumber (07X-2 and 07X-3) with different heat-resistant were used in the experiments. An orthogonal experimental design L16 (45) was used to optimize the callusing induction process through seedling age, cotyledon size, IAA, NAA and 6-BA. The results showed that:Callusing ability of cotyledon explants derived from 6-day-old in vitro seedlings of 07X-2 or 7-day-old in vitro seedlings of 07X-3 was evaluated on MS medium containing 0.1mg/L IAA,1.5mg/L 6-BA and 0.1mg/L NAA or MS medium containing 1.0 mg/L 6-BA and 0.1 mg/L NAA. Also cotyledons were cut in half and used as explants.Green and compact callus of 07X-2 were selected and turned into MS medium containing different PGRs for shoot regeneration. The results showed that:High quality and frequently shoot induction of 07X-2 were obtained on MS medium containing 2.0 mg/L 6-BA,0.1 mg/L IAA,3.0 mg/L AgNO3.Selected adventitious shoots with an average height and segregated into small clusters containing two or three shoots for shoot elongation. These shoots clusters were transferred to MS medium containing different concentrations of 6-BA or KT. The results showed that:The shoots elongated well in MS medium containing 0.05 mg/L 6-BA.2 Heat-resistant mutants in vitro selectionCallus of 07X-3 that were green and compact were selected and placed on the condition of 38℃,42℃,45℃with different time of 8h,12h,16h,20h. The results showed that:The best condition for heat resistant filter at 45℃for 12h.Survival callus of 07X-2 and 07X-3 were selected and cultured. The results showed that:Two kinds of heat stress can significantly reduce the survival rates of callus, extend the time for buds. 3 Identification the heat-resistant of plantsMother plants, regenerated plants D1 and heat-resistant regenerated plants were heat treated in the greenhouse. After treatment, their physiological indexs were measured in the Lab. The results showed that:Heat-resistant regenerated plants and regenerated plants D1 of 07X-2 were more resistence to heat than the mother plants, while the ratio of 07X-3 were seperately twenty percent and forty percent than the mother plants...