Construction Of High Efficient System In Vitro Gynogenesis In Summer Squash (Cucurbita Pepo L.)

Embryo sac plants (R0) via in vitro unpollinated ovary or ovules culture were abtained from 15 genotype squash (Cucurbita pepo L.) material The results showed that inductivity were influencedd by genotyp and medium.Hot stock in dark had an positive role, the best treatment was at 35℃for 5 days.Among the factor affected embryogenesis , 2,4-D was important ,while it was not absolutely necessarily. It was the best for treat by 4mg/L 2,4-D for 7 days . The ratio of NH4+ / NO3- also affected embryogenesis .It was better for ratio 1:1 when added 4mg/L 2,4-D ,while the best ratio was 2:1 without 2,4-D.One genotype material was used for radiated pollination in vitro culture .The results showed that the ratio of regenerated plants was strongly influenced by radiation dose and inoculation method. In sum the best dose was 100 Gy and the best inoculation method is without hull .Comparision to different ploidy indentification method for regenerated plants , flow cotometry for identification of ploidy is convenienct and accurate , but it is expensive. Chloroplast counting in guard cells was an effective tool.Morphologic observation and embryology results showed that the regenerated Embryo sac plants was via embryogenesis. Embryoid origined from Embryo sac .A acclimatizing and transplanting technique for the tube plantlet was successfully established.It is an simple,operater easily, practiceal and high survival rate for transplanting of the regenerated plants.More than 1200 regenerated Embryo sac plants (R0) were abtained and 784 were planted. R0 plant showed separation of leaf, vine, melon shape and colour.Tetraploid plant were huge. The seeds over 120 line of R0 are being planted in fields.