Abstract: This paper presents some preliminary results of the experiments conducted in 1953 and 1954 on the temperature and duration requirements for vernalization of wheat varieties cultivated in the East China. In determining the requirements for vernalization of those varieties, the method described by Ivanov (1951)was used. Seeds free from any disease, were selected for uniformity. They were wrapped in gauze and tagged with cloth-labels marking the variety, temperature and duration for vernalization. Prior to the vernalization-treatments, the seeds already prepared were soaked in water at room temperature for 24 hours. The seed-moisture was brought approximately to 45% before the seeds were made to germinate at 10℃ (but without- the radicle penetrating the coat). During vernalization the seeds were kept at 0-3℃ (or 2-4℃ as in 1953), 5-8℃, and 10-12℃ for 5 to 45 days at an interval of every 5 days. Non-vernalized seeds served as controls. Both the vernalized seeds and the controls were sown on the same date in spring when the soil temperature had become higher than 10℃ and the daily possible sunshine longer than 12 hours thereafter. The temperature and duration requirements of the different varieties for the Completion of the vernalization process were judged from the earing dates and their unifomity. Results thus obtained are briefly summaried as follows; 1. The temperature and duration requirements for vernalization have been worked out for 104 varieties. In accordance with their characteristics in response to vernalization-treatments, these varieties may be divided into 3 groups: (1) Spring type Controls eared as normally as the fully-vernalized plants. Those from seeds vernalized for different lengths of periods showed no significant difference in earing dates. In most cases, acceleration in earing due to vernalization was 0-2 days, indicating that the vernalization-stage was very short, probably less than 10 days. 27 varieties belonged to this type (Tab. 1. Var. no. 1--27). (2) Semi-winter type The optimum temperature for vernalization of these verieties was 5-8℃. In accordance with their response to vernalization treatments. varieties of this group may be farther subdivided into 2 groups: Group A. This group was distinguished in its wider range of temperatutre for vernalization process. At a temperature higher than 10℃, vernalization process still proceeded at some moderate rate. Acceleration in earing due to vernalization treatments was 4-11 days. There were 8 varieties belonging to this group (Tab. 1. Var. no. 28-35). Group B. Controls failed to ear. Temperature higher than 10℃ was probably too high for the normal process of vernalization. Vernalization-stage at 5-8℃ was 25-30 days in length, varying with varities. 23 varieties belonged to this group (Tab. 1. Var. no. 36-58.). (3) Winter type Controls failed to ear. Temperature higher than 10℃ was too high for the normal process of vernalization. Vernalization proceeded slower at 5-8℃ than at 0-3℃. The duration for the quickest completion of vernalization at 0-3℃ was 30-45 days, varying with varieties. 2. The varietal characteristics in vernalization-stage was found to be closely connected with the winter conditions under which the varieties had been formed and cultivated. Varieties grown in the regions lying between January isotherm -2℃ and 0℃ were mainly of winter type; those cultivated in the regions south of January isotherm 4℃ were mainly of spring type. Varieties distributed in the regions south of January isotherm 0℃ and north of January isotherm 4℃ were mainly of Semi-winter type (Tab. 2).