基于主成分分析的玉米萌发期抗旱性综合评定

试验在人工气候室内利用称重法精确控制75%和35%土壤相对含水量(RWC),通过分析播种后7 d不同玉米品种的发芽率、根系生长、干物质转化等对干旱胁迫的响应差异,对10个玉米品种进行萌发期抗旱性综合评定。结果表明,干旱胁迫降低了玉米的发芽势、发芽率、发芽指数、种子萌发抗旱指数、地上部与地下根物质积累和贮藏物质转运率,增大了根冠比。利用主成分分析与热图分析得出,玉米萌发期抗旱鉴定的四级指标分别为干物质积累量、发芽指数和种子萌发抗旱指数;根长、根冠比和根干重等;根体积和贮藏物质转运率;发芽势。将指标按照对抗旱性影响的差异分为4类,发芽率、发芽指数、种子萌发抗旱指数;根体积、贮藏物质转运率;根冠比;根长和芽长。依据综合值对10个玉米品种萌发期抗旱性评价,其抗旱性强弱依次为浚单29、蠡玉35、五谷704、吉祥1号、先玉335、博优989、郑单958、伟科702、农玉2号、登海605。

Integrative Evaluation of Maize Drought Tolerance in Germination Period by PCA Method

Seeding pot experiment had been conducted with 35% and 75% relative soil water content to evaluate the drought tolerance of 10 summer maize varieties in the germination stage in the climate chamber. The results showed that seed germination potential, germination rate, germination index, aboveground and belowground biomass, storage substance remobilization rate, plant height and root length after seedling had been significantly decreased under drought stress while the root/shoot ratio increased. Principal component analysis (PCA) and heat map analysis showed that four levels of indexes had been established, dry matter, germination index and germination drought resistance index; root and shoot relationship; root volume and the storage substance remobilization rate; germinating potential. In addition, all indexes were divided into four categories according to the response of drought on seedling emergence, germination rate related parameters; root volume and the storage substance remobilization rate; root-shoot ratio and root length; plant height. PCA and heat map clustering analysis showed that drought tolerance of 10 varieties was in the order of XD29, LY35, WG704, JX1, XY335, BY989, ZD958, WK702, NY2, DH605.