为探明稻茬烤烟湘烟7号下部烟叶最适采收成熟度,在湖南桂阳烟区开展了下部烟叶不同成熟度采烤试验.结果表明:随下部烟叶采收成熟度提高,鲜烟叶的SPAD值下降;正组烟叶比例下降,杂色烟叶比例增加;烟叶外观质量提高;烟叶总糖、还原糖、烟碱含量及两糖比增加,氮碱比下降;评吸质量下降,上等烟比例下降,均价下降.因此,为提高上等烟比例和烟农收入,湖南桂阳烟区湘烟7号下部烟叶应在SPAD值为26.26～30.33时及时采收.“,”To clarify the suitable harvest maturity of Xiangyan 7 of the lower leaves of paddy-tobacco, the curing test of lower tobacco leaves with different maturities was carried out in Guiyang tobacco area of Hunan in China. The results showed that the SPAD value of fresh tobacco and proportion of normal group decreased, the proportion of mottle tobacco increased, the appearance quality of tobacco leaves became worse, the level of total sugar, reducing sugar, nicotine and reducing sugar/total sugar increased, and the total nitrogen/nicotine decreased with increased harvest maturity of lower tobacco leaves. It could cause lower smoking quality, lower proportion of high-class tobacco leaves and lower average price if the harvest of lower tobacco leaves was delayed. Therefore, the lower leaves of Xiangyan 7 in Guiyang tobacco area of Hunan should be harvested early. Suitable harvest maturity required light green leaf blade, light green midrib, and curl leaf margin. When the SPAD value of fresh tobacco was 26.26～30.33, it could be used as a reference for guiding the appropriate harvest maturity of lower paddy-tobacco leaves of Xiangyan 7.