苗期甘蔗氮高效基因型评价指标的筛选

Screening of Sugarcane with High Nitrogen Efficiency at Seedling Stage

本研究通过低氮压力选择,筛选出甘蔗氮高效种质,分析影响甘蔗氮高效的重要指标,为甘蔗氮高效育种及栽培提供理论依据。以58份甘蔗种质资源为材料,在苗期采用正常供氮(2 mmol/L N)和低氮(0.2 mmol/L N)处理,分析甘蔗植株形态、干重及氮素在各器官中累积分配的特征。通过主成分分析方法筛选影响甘蔗氮高效利用的重要指标,通过聚类分析对58份种质进行聚类。结果表明,低氮(0.2 mmol/L N)处理可以明显从植物形态区分不同种质的氮利用差异,58份种质低氮条件下的干重范围为0.64~14.75 g/株,氮累积量为5.53~63.00 mg/株,氮利用率范围为115.40~279.30 g/g。对低氮压力下甘蔗干重及氮累积等25个指标进行主成分分析后,提取出4个主要成分,总贡献率为92.35%。通过高、低氮条件下与氮利用效率有关的氮转移系数及基因潜力等19个指标分析后提取出5个主成分,总贡献率为82.21%。影响甘蔗氮高效的重要指标有甘蔗的干重(全株、叶、根)、氮累积量(全株、叶、茎)、氮利用率(全株、叶)、叶的相对氮利用率、茎的基因潜力、茎的相对干物质量和茎的相对氮累积量。经聚类分析后初步将58份甘蔗种质分为氮高效基因型、偏氮高效基因型、偏氮低效基因型和氮低效基因型。

The purpose of the experiment is to screen high nitrogen use efficiency(NUE)genotypes under a low nitrogen pressure selection system.Furthermore,the important indexes which affecting the NUE of sugarcane were analyzed.The results could provided a theoretical basis for the high NUE breeding and cultivation of sugarcane.In the study,seedlings of 58 sugarcane genotypes were evaluated in a hydroponic experiment with low-N(0.2 mmol/L N)and normal-N(2 mmol/L N)treatment.The growth,dry biomass and N cumulative and distribution characteristic in various organs were evaluated according to descriptive statistic,principal component analysis and cluster analysis.The results indicated that morphology,biomass,nitrogen efficiency traits showed high genotypic variation for N treatments.Under low-N treatment,the dry biomass of 58 genotypes varied from 0.64 to 14.75 g/plant,nitrogen accumulation was from 5.53 to 63.00 mg/plant and NUE was from 115.40 to 279.30 g/g.Four factors were extracted with variance contribution approximated to 92.35%,according to 25 parameters such as dry biomass and N uptake with N deficiency.And another five factors were extracted with variance contribution approximated to 82.21%,according to 19 parameters under both normal and low N treatment such as nitrogen transfer coefficient,genetic potential.The data revealed that dry biomass(whole plant,leaf,root),N uptake(whole plant,leaf,shoot),NUE(whole plant,leaf),leaf relative NUE,shoot relative dry weight,shoot relative N uptake,shoot genetic potential were the key factors that involved in sugarcane high NUE.58 sugarcane genotypes were clustered into four group:high NUE group,slightly higher NUE group,slightly lower NUE group and low group.