Studies on cotton breeding technique resistant to Fusarium and Verticillium wilts

Chinese. 研究棉花抗枯、黄萎病育种技术，选育棉花抗枯、黄萎病的多抗性新品种。试验采用致病力强的菌种，培养备制成棉枯萎病棉籽粉载菌体和棉黄萎病孢子悬浮液，研究不同菌量、不同接菌方法、致病温度因素、病圃接菌选择及多抗病性育种选择技术指标。播前土壤接棉枯萎病菌棉籽粉载菌体，棉苗2片真叶时，伤根接黄萎病菌孢子悬浮液，盖膜保温诱导发病，淘汰感病群体及感病个体。大田病圃是在重病地接种发病棉杆，移栽时再用棉黄萎病菌孢子悬浮液沾根，发病高峰淘汰棉枯、黄萎病感病群体及感病个体，结合丰产、优质性状的遗传选择，培育出抗病棉花品种。该项技术是在研究棉花苗期诱导抗性和大田病圃筛选相结合构建的新方法。

English. The cotton breeding technique resistant to both Fusarium wilt and Verticillium wilt should be studied in order to gain resistant cultivars based on it. The method of inducing cotton multi-resistance by selection with artificial inoculation was adopted in the study. The strong virulence pathogen strains of wilt diseases were cultured in autoclaved cottonseed to make pathogen carrier respectively. Fusarium oxysporum f. sp. Vasinfectum was inoculated with cottonseed meal at the dosage of 90 gand#8226;m-2 in nursery soil before sowing. Then each seedling was inoculated with 10 ml of Verticillium dahliae spore suspension at the concentration of 2×107 spores per milliliter by watering injured roots at 2 true leaf growth stage. The nursery bed was covered with polythene film to keep the average bed temperature of 2025℃. Then the susceptible varieties or plants would show disease symptoms and should be eliminated. And the resistant plants of resistant variety were selected and transplanted to the field which was inoculated with the diseased cotton plant 1500 kgand#8226;ha-1 beforehand. Each seedling was inoculated with Verticillium dahliae spore suspension by dipping injured roots when they were being transplanted. And the susceptible varieties or plants were eliminated again in field. It was shown that this breeding technique was practicable and efficient. The cotton varieties with multi-resistance, good fiber quality and high yield production, were bred in our breeding practice with this technique adopted.