关键词: 小麦, 豫麦2号, 骨干亲本, 系谱分析, 遗传贡献, 共祖先度法

Abstract: Yumai 2（Baofeng 7228）is a representative variety in the Huanghuai wheat region，possessing excellent characteristics，including high yield，stress resistance，wide adaptability，and outstanding combining ability. It has played a significant role in production，and has been a key backbone parent for decades. This study systematically compiled the pedigree information of Yumai 2 and its 887 derivative varieties（lines and intermediate materials）. By constructing pedigree network，the genetic transmission pathway from Yumai 2 to the third⁃generation varieties was revealed，the distribution characteristics of derivative varieties（lines and intermediate materials）across different generations，approval periods，and geographical regions were analyzed，and its genetic contribution was quantitatively assessed using the coefficient of coancestry method，aiming to provide scientific support for the high⁃quality and sustainable development of wheat breeding in the Huanghuai wheat region. The results showed that the derivative family of Yumai 2 exhibited a typical‘ pyramid’ expansion structure，with 36 first⁃generation（directly derived） varieties（lines and intermediate materials），137 second⁃generation varieties，and 714 third⁃generation（deeply derived）varieties，accounting for 80.5% of the total derivative varieties（lines and intermediate materials）. In terms of temporal distribution，the number of approved（bred）varieties （lines and intermediate materials） increased rapidly from 24 during 1982—2000 to 482 during 2021—2025，with the number approved in the most recent five years alone exceeding the total of the previous 20 years. Zhoumai 16，Aikang 58，Zhoumai 18，and Zhengmai 366 were identified as the second⁃generation super parents，collectively supporting 84. 5% of the third⁃generation varieties. The average genetic contribution rate of Yumai 2 to the second⁃generation varieties reached 26.4%，higher than the theoretical expectation（25.0%） under Mendelian segregation，demonstrating excellent combining ability.The derivative varieties（lines and intermediate materials） were highly concentrated in Henan Province（60.9%），Anhui Province（13.5%），Shaanxi Province（8.3%），and Shandong Province （5.2%），basically covering the core production areas in the Huanghuai wheat region. Among the leading wheat varieties recommended in Henan Province from 2023 to 2025，76.3% contained the pedigree of Yumai 2，indicating that its pedigree still occupied a core position among current mainstream varieties.

Key words: Wheat, Yumai 2, Backbone parent, Pedigree analysis, Genetic contribution, Coefficient of coancestry method