Study On Seed Germination Characteristics Of Peach Rootstock

Peach [(Prunus Persica(L.)Batsch)] is a plant of Prunus in Rosaceae,with ornamental flowers and edible fruits,which has high nutritional value and economic benefits.China is rich in peach germplasm resources,and the peach cultivated area and fruit yield rank first in the world,but the peach seedling breeding technology is generally not high.At present,the main method of peach seedling breeding is grafting of solid stock,so the selection of peach stock is very important.During the cultivation of peach seedlings,the problems of difficult germination of rootstock seeds and low germination rate often occur due to the reasons of hard seed shell,late ripening of seed embryo and the existence of substances inhibiting germination in seed coat.In order to obtain higher germination rate of rootstock seeds and well-developed seedlings,an appropriate method to break seed dormancy is needed for later inoculation and grafting.Aiming at the important problems of low germination rate and long germination time of peach rootstock seeds,this paper studied the effects of harvest maturity,seed cap restriction,low temperature refrigeration and fungicide treatment on seed germination and seedling growth of peach rootstock seeds,and discussed the characteristics of dormancy of peach rootstock seeds and the methods of dormancy lifting through various aspects.This study provided theoretical basis for the study of dormancy process,dormancy release and germination of peach seeds.The main research results are as follows:1)Seed coat had a significant effect on seed germination and growth of peach rootstock.Removal of seed coat at different degrees was beneficial to breaking seed dormancy,but there were differences among different treatments.The seed germination rate reached 98.33% after removal of seed coat at the top,which was significantly different from the control.After ring cutting treatment and loosening treatment of seed coat,the seed germination rate was generally not high,and the germination rate of ’Shengzhoumaotao’ only reached 31.67%.The plant height and stem diameter of ’Longquanshanmaotao’ reached 19.27 cm and 0.22 cm,and the plant height and stem diameter of ’Longquanshanmaotao’ were well developed in the growth process without deformed leaves,which was significantly different from other varieties.Among the five varieties,’GF305’ had the lowest plant height and stem diameter,only 14.37 cm,0.16 cm,the germination rate and seedling growth were not ideal.2)Fruit harvest maturity has significant effect on peach wood seed germination growth,overall with increased maturity,’Nemaguard’ and ’Taozhen JS-4’ two varieties peach wood seed germination rate,germination potential and germination index were different degree increase,and the seed germination rate and uniformity significantly increased,but the differences between the varieties,when fruit maturity is relatively low,the difference of germination rate between the two cultivars was significant,and the difference was significantly reduced when the fruit maturity reached 90 %.After sowing,the total plant height and stem diameter of the seedlings increased with the increase of maturity,but the difference was not significant.The leaf deformity of’Nemaguard’ seedlings was serious.(3)Cold storage had a significant effect on the germination and growth of peach rootstock seeds.With the prolongation of cold storage time,the germination rate,germination potential and germination index of seeds were significantly increased,and the germination speed and uniformity were significantly enhanced.Under the same cold storage time,the germination index of 90% mature seeds was significantly higher than that of other maturity,and the germination rate of 90% mature seeds could reach 100% after 30 days of cold storage at room temperature.Low temperature and cold storage had a significant effect on seedling growth after sowing.In general,the plant height and stem diameter of seedlings increased to varying degrees with the prolongation of low temperature,and the growth of 80% and 90% mature seedlings was generally better than that of 70% and 10% mature seedlings.When the cold storage time reached 50 days,the deformity disappeared.(4)The 11 fungicides used in this study all had inhibitory effects on seed mildew during cold storage.Among them,five fungicides,45% thiothiol mixture,75%chlorothalonil,45% midaxanide,80% mancozeb and 25% pyrazolate,had significant antibacterial effects on seeds of the two varieties of peach,and the seed mildew rate was not more than 10%.80% mancozeb had the strongest effect on seed germination,and the germination rate of the two varieties of peach rootstock seeds reached 81.67%and 66.67%,respectively.