改良S_1后代轮回选择在玉米群体改良中应用的研究 Ⅰ.直接响应与相关响应

Studies on the Application of Modified S_1 Progeny Recurrent Selection in Maize Population Improvement I. Direct and Correlated Responses

以玉米群体中综3号为材料,研究改良S_1后代轮回选择在玉米群体改良中的应用。通过对中综3号三轮改良S_1后代选择群体的二年三点比较试验,研究改良S_1后代轮回选择的直接响应与相关响应。结果表明:以籽粒产量为主要目标的改良S_1选择,每轮群体自身产量可获得8％-10％的遗传增益,群体S_1后代籽粒产量可获得近14％的增益。单穗籽粒产量的提高,从穗部性状看,主要是穗长的增加和千粒重提高的结果。每行粒数有所增加,但不显著,穗行数趋于减少,穗粗变化不大。应用改良S_1选择对产量性状进行选择时,若兼顾抗性,则效果更佳。本研究中综3号群体经三轮改良S_1选择后,抗倒性、抗青枯性得到了极显著改良,每轮倒伏率下降16.5％-18.2％,青枯病株下降10.1％-10.3％。但在选择籽粒产量时,若同时想降低株高、穗位,将难以奏效。

Three cycles of modified S1 progeny recurrent selection [ZZ3 (MS1)] of Zhong Zong No.3 (ZZ3) have been completed. The direct and correlated responses of S1 recurrent selection in ZZ3 (MS1) were evaluated in 1992 and 1993 at three lacations. The average population grain yield per mu was increased by 8 to 10% per cycle (significant at P< 0.01), and the increase of the average grain yield of S1 progeny was nearly 14% per cycle (significant at P≤ 0.01). The increase of grain yield per plant relied mainly upon the increases of ear length and 100 kernel weight. Selection was very effective for both traits; The increases were 6.2 to 7.0% and 5.4 to 5.7% respectively (both were significant at P≤0.05). The number of rows per ear decreased with selection, and the number of kernel / row / cycle only increased sightly. But the ear diameter did not change. Plant height and ear height increased and lodging and wilting decreased with selection too, but days to silk emergence and pollen shedding remained throughot the cycles.