Research on the Characteristics of the Soybean Leaf and Petiole Change in Its Genetic Improvement in Jilin Province

[Objective] The reference for the improvement of high-yielding soybean and the utilization of its germplasm resources was provided through the research on the compound leaf area and the change of diameter and length of petiole of soybean in Jilin province. [Method] The leaf at the 4th,10th and 16th node of 42 main soybean varieties,which had been applied in Jilin Province since 1923,was researched in the change trend of their compound leaf area,the length and diameter of petiole among years. [Results] In Jilin Province the curve of S:slow-fast-slow in soybean compound leaf area and petiole growth was showed. The process of compound leaf area and petiole growth was different and there were 3-5 days later in the growth of petiole length than the growth of leaf area; and 5-7 days later than the growth of petiole diameter. The area of the leaf at the 4th soybean node was increased with the increment of its releasing year,but there was declining trend in the area of the leaf at the 10th and 16th soybean node with the increment of its releasing year. The length and diameter of petiole of soybean at all of nodes in were increased with the increment of its releasing year. [Conclusion] The leaf area at the bottom layer of soybean variety mainly applied in production in Jilin Province was increased at middle and upper layer was decreased with the increment of its releasing year and also the length and diameter of petiole grew largely.