耐低氮烟草基因型的筛选及其氮效率类型

摘要

Genotypes with tolerance to low nitrogen (N) are preferred in improving N use efficiency of tobacco and reduce nitro-gen pollution. In this study, seedlings of 74 tobacco genotypes were evaluated in a hydroponic experiment with low-N (0.5 mmol L–1) and normal-N (5.0 mmol L–1) treatments, and the genotypes were evaluated according to descriptive statistics, factor analysis and cluster analysis. The root volume, root biomass, N accumulation in stalk and leaf, and aboveground biomass varied greatly across genotypes with the variation coefficients of 0.37–0.68 in low-N treatment and 0.38–0.64 in normal-N treatment. The prin-cipal components under both N levels were similar, showing that the N accumulation in stalk and leaf and aboveground biomass were important components. According to evaluation indexes Heatmap clustering and scatter diagram analysis of N efficiency comprehensive value, 15 low-N tolerant genotypes were screened out, accounting for 20.3% of varieties tested, including eight genotypes of high-efficiency under low-N but low-efficiency under normal-N, six genotypes of low-efficiency under both low-N and normal-N, and one genotype of high-efficiency under both low-N and normal-N. In addition, eight genotypes were found to be sensitive to low-N, including six genotypes of low-efficiency under low-N but high-efficiency under normal-N and two geno-types of low-efficiency under both low-N and normal-N. We primarily identified 14P9 as the low-N tolerant and N-efficient to-bacco and Zhongyan 100 and K394 as the low-N sensitive and N-inefficient tobacco.%筛选耐低氮及氮高效的烟草基因型是提高氮素利用效率,减少氮污染的一种有效途径.本文采用营养液培养方法,以低氮(0.5 mmol L–1)和正常氮(5.0 mmol L–1)处理74个烟草基因型幼苗,通过指标统计、因子分析、聚类分析来确定评价指标,并筛选出耐低氮基因型.不同基因型烟草的根系体积、根系生物量、茎叶氮累积量、地上部生物量变异明显,低氮和正常氮处理的变异系数分别为0.37~0.68和0.38~0.64.两种氮水平下的主成分基本相似,并表明茎叶氮累积量和地上部生物量起主要作用.根据评价指标的Heatmap聚类和氮效率综合值散点图分析结果,筛选出15个耐低氮基因型,占供试材料的20.3%,其中8个属于低氮高效正常氮低效型,6个属于低氮低效正常氮低效型,1个属于低氮高效正常氮高效型;还筛选出8个低氮敏感基因型,其中6个属于低氮低效正常氮高效型,2个属于低氮低效正常氮低效型.初步确定14P9为耐低氮且氮高效基因型,中烟100和K394为低氮敏感且氮低效基因型.