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甘薯杂交育种工作,首先需要通过有性杂交获取大量杂交种子,以培育出多样性的杂种实生苗。由于每株实生苗均具备不同的形态特征、生物学特性和经济性状,因此大群体的实生苗,是甘薯选种的丰富材料。但在甘薯实生苗的培育过程中,经常发生死苗现象,死苗率一般达1—5%,严重时可达10%左右,造成大量实生苗的损亡,降低了选择的机率,影响甘薯杂交育种工作的开展。1979年我们研究鉴定这种实生茵死苗现象是由立枯丝核菌(Rhizoctonia solani Kühn)引起的。据前人报道,这种病菌的寄主范围较广,如棉立枯病,甜菜根腐病、马铃薯黑痣病及茄立枯病等同属这一种寄生菌,至今有近200种植物能感染此病。
Sweet potato hybrid breeding work, first of all need to obtain a large number of hybrid crossbred seeds to breed a variety of hybrid seedlings. Because each plant has different morphological characteristics of seedlings, biological characteristics and economic traits, so a large group of seedlings, sweet potato is a rich selection of materials. However, in the process of sweet potato seedling cultivation, the phenomenon of dead seedlings often occurs. The rate of dead seedlings is generally 1-5%, and in severe cases about 10%, resulting in the loss of a large number of seedlings, reducing the probability of selection and affecting sweet potato Hybrid breeding work carried out. In 1979, we investigated the identification of this deadly shoot phenomenon caused by Rhizoctonia solani Kühn. According to previous reports, this host has a wide range of host bacteria, such as cotton tick, beet root rot, potato black mole disease and so on. It has nearly 200 kinds of plants that can infect This disease.