断根对冬小麦竞争能力与产量的影响

 采用简化的deWit替代系列法研究了盆栽冬小麦‘长武135’（Triticum aestivum cv. Changwu 135）在拔节初期断根对冬小麦根冠关系、竞争能力及其与产量性状的关系。无论干旱或湿润，单栽条件下断根降低了小麦的根冠比，在混栽条件下，断根小麦的相对穗重和相对地上部生物量均显著低于未断根小麦，说明断根降低了小麦的竞争能力。根冠比越大竞争能力越强，即作物的竞争能力与根冠比存在正相关关系。单栽湿润条件,断根降低了小麦的穗重和籽粒产量，而在中等干旱条件下，断根小麦穗重和籽粒产量高于未断根小麦 。说明在水资源充分的条件下，较高的作物个体竞争能力则具有较高的生产能力，而在水资源有限的情况下，降低作物个体竞争能力反而提高了群体籽粒产量。

EFFECT OF ROOT EXCISION ON COMPETITIVE ABILITY AND YIELD OF WINTER WHEAT

Aims Decreasing root biomass might be an effective way to increase crop production under drought stress. A winter wheat with root excision was chosen to determine whether 1) root biomass or R/S (root/shoot ratio) is reduced by root excision, 2) competitive ability is reduced by root excision and its link with R/S and 3) competitive ability influences crop production. Methods The effects of root excision on root-to-shoot relations, competition ability and yield characters of winter wheat (Triticum aestivumcv Changwu135 ) were investigated using a deWit replacement series in a pot study. Root excision was conducted from tillering to jointing. Two culture methods (mono and mixed) were compared. The effect of drought was estimated from two groups of plants, one group maintained at 75% soil FWC and a second at about 50%, after root excision. Soil water was controlled by weight daily. At grain maturity, plants for each pot were harvested, divided into shoot and root, dried and weighed. Important findings The R/S was significantly reduced after root excision in monocultures irrespective of water condition. Furthermore, spike weight and aerial biomass of wheat after root excision were reduced in mixed cultures, indicating that the competitive ability of wheat was reduced after root excision. There was positive correlation between competitive ability and R/S in crop varieties, i.e., the crop with the higher R/S had higher competitive ability. In monocultures, spike weight and yield of wheat after root excision were reduced with a complete water supply. However, the spike weight and yield of wheat w ere higher after root excision than without excision under drought conditions. This study indicated that the crop with higher competitive ability has a higher production capability with a complete water supply and that the crop could obtain higher yield with the reduction in individual competitive ability under limited water.