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采用 6个国际玉米小麦改良中心的热带玉米自交系为亲本 ,按Griffing方法 2组配成双列杂交 ,在高氮和低氮条件下对各主要性状进行鉴定 ,并估算其遗传参数。结果表明 ,从高N到低N ,籽粒产量降低程度最大 ,降减系数 (RI)达0 4845 ,与叶绿素含量降低程度几乎一致。自交系间和杂交组合间在产量的降解系数上有明显的遗传差异。低氮条件下 ,籽粒产量、穗行数、百粒重、穗长、单株穗数、穗位以下绿叶数、雌雄开花差期、穗位叶面积、地上部干重和株高有显著的加性遗传方差 ,同时 ,籽粒产量、穗长、穗粗、雌雄开花差期、叶绿素含量、地上部干重、行粒数、百粒重、单株穗数和株高有显著的显性遗传方差。狭义遗传力较高的性状包括株高、穗长、穗位叶面积、百粒重、穗行数和穗位以下绿叶数。研究显示 ,通过轮回选择在自交系中积累较多有利基因 ,组配优良杂交组合来提高玉米耐低氮的能力是可能的。
Six maize inbred lines of Maize Wheat Improvement Center were used as parents to identify the major traits according to Griffing method and double genetic analysis. The genetic parameters were estimated under high nitrogen and low nitrogen conditions. The results showed that from high N to low N, grain yield decreased the most, and the reduction coefficient (RI) reached 0 4845, which was almost the same as that of chlorophyll content. There were significant genetic differences in yield coefficients between inbred lines and cross combinations. Under low nitrogen conditions, grain yield, number of ears per plant, grain weight per plant, spike length, number of panicle per plant, number of green leaves per panicle, number of male and female flowering stage, leaf area at ear position, dry weight above ground and plant height were significant Additive genetic variance. At the same time, there was significant dominant genetics of grain yield, ear length, ear diameter, difference of male and female flowering, chlorophyll content, aboveground dry weight, grain number per line, grain weight per plant, panicles per plant and plant height variance. Traits of narrow heritability include plant height, spike length, leaf area at the ear, 100-grain weight, number of rows per ear and number of green leaves below the ear. Studies have shown that it is possible to improve the ability of maize to tolerate low N by combining good crosses with more favorable genes in inbred lines through the cycle selection.