Preliminary Study On The Evaluation System Of Resistance To Early Blight Of Virus-Free Potato Test-Tube Seedlings

Potato(Solanum tuberosum L.)is a perennial herb with edible tubers and both food and vegetable.It belongs to solanaceae,Solanum genus,and is a barren resistant crop with high yield and strong adaptability.Together with rice,wheat,sorghum and corn,it is known as the world’ s five major crops.Potato diseases(viral diseases,blight,scab,etc.Early blight mainly infects solanaceae crops,mainly damages the leaves of plants,but also infects stem,petiole and tuber and other parts of plants.By collecting potato early blight materials in xinjiang,the evaluation system of resistance to early blight of virus-free potato test-tube seedlings was preliminarily studied.The main research results are as follows:(1)Through the collection and separation of potato early blight materials,30 strains of early blight were obtained,with round size,gray black and uniform growth of aerial hyphae,and slightly different colony color.(2)Compare and analyze the growth situation of potato early blight pathogen with 6 treatments of different medium,temperature,pH value,ultraviolet irradiation time,carbon source and nitrogen source.Among them,the growth amount of hyphae increased gradually with the change of PSA and PDA medium over time,with better performance.15-20℃,pH value in the range of 7-8,suitable to the growth of hypha;Compared with other treatments,the growth of mycelia was better with soluble starch as the carbon source.When potassium nitrate was added as substrate nitrogen source in the culture medium,the growth of mycelia also showed good performance.(3)The incidence was observed in all the 6 groups of early-disease pathogen suspensions with different concentration gradients in the experiment,and the higher the concentration of inoculation was,the higher the incidence rate was,and the larger the observed plaque was.Early epidemic strains under the condition of 25 ℃ and 30℃,in vitro leaf can also come on,similar disease spot situation and the disease spot in the field.(4)Inoculated with six varieties have different degree of incidence,the vaccination after a week,when the index is higher than 40,the incidence is higher than 70%,can determine the basic’Zi Hua Bai’,’Atlantic’,’No.3 of Zhong Shu Series’,’Xia Zhai 65’and’Favorita’,disease index of less than twenty,incidence of less than 20%,summer poti to disease-resistant varieties can be determined.