Induction And Identification Of Polyploid Physalis Pubescens L.

Physalis pubescens L.is a multi-purpose horticultural plant of the genus Solanaceae,which has high medicinal value,nutritional value,ornamental value and good development prospect.At present,there are many problems in the products of Physalis pubescens L.,such as small size and too many seeds in the fruit,which seriously affect the appearance,flavor,taste and process.Polyploid breeding is a common breeding method used in horticultural crops,which usually leads to fruit enlargement,seed reduction and fruit quality improvement.In this study,colchicine was used to induce polyploidy of three cultivars of Physalis pubescens L.,and the induction technology was constructed.The polyploidy induced in this study might provide germplasm materials for the quality improvement of Physalis pubescens L.,and promote the development of Physalis pubescens L.industry.The main results were as follows:1.There were significant differences in the germination rates at different temperatures among ’Dahuang’,’Tiebaqing’,and ’Lilitian’.With the increase of temperature,the germination rate of seeds increased.The optimum germination temperature for the three cultivars was 37℃.’Dahuang’ showed hightest germination rate.Seed dormancy was found in the aged seeds stored at room temperature,and cold treatment at 4℃(Id、2d、3d、4d)could break seed dormancy.Among the treatments,cold treatment at 4℃for 1 day was the best,with a germination rate of 83.45%.With the prolongation of cold treatment time,the germination rate decreased.’Dahuang’ showed significant decrease in seed germination rate when treated at 4℃ for different time(i.e.Id、2d、3d、4d).2.The treatment of soaking for 7 days by colchicine showed the best vigorous germination for Physalis pubescens L..Except for water control,the treatment with the largest number of germination were 100mg/L for 12 hours.The treatment time and concentration of colchicine with the best doubling effect of the three varieties at 7d,12d and 30d were as follows:’Tiebaqing,12h,400mg/L;12h,200 mg/L;12h,100 mg/L;`Dahuang’:12h,100 mg/L;12h,400 mg/L;12h,100 mg/L;’Lilitian’:12h,100 mg/L.The results of tissue culture induction method showed that the treatment time of 3 days or 5 days was the best,and the concentration of colchicine was 50 mg/L and 100 mg/L,respectively;The phenotypic doubling effect of three cultivars was the best under different treatment time with the concentration of 50 mg/L of colchicine,and the highest mortality rate with the concentration of 100 mg/L.Compared with impregnation method,mixed culture method showed higher induction rate,and was more suitable for polyploidy induction of Physalis pubescens L..3.Comparing the tetraploid and diploid of Physalis pubescens L.,it was found that:the fruit of tetraploid Physalis pubescens L.was bigger,the deformity of leaves was rough,the vein of leaves changed obviously,and the stem became thicker;the stomatal length became bigger,the density decreased;the pollen grains became bigger and the pollen vigor decreased;Flow cytometry observation showed that the DNA content of diploid increased,and the DNA content of homologous tetraploid was twice as that of diploid plants.