多效唑对谷子茎秆特征及抗倒性的影响

为研究多效唑对谷子茎秆性状及其穗颈的抗倒性影响，采用随机区组设计，在谷子拔节期前(A1)、拔节期(A2)和孕穗期(A3)分别叶面喷施300 mg·L^-1的多效唑，以清水作为对照(CK)，对谷子主要茎秆性状、倒伏指数、穗颈参数及产量进行测定。结果表明：①与CK相比，施药后谷子植株的生长发育受到明显抑制，喷施时期越早，抑制效果越明显，株高越低，2个品种的株高均在A1处理下达到最小值，同时植株重心高度与株高的比值变化趋势与之相一致。②基部节间茎粗增大，在A1处理时达到最大值。随多效唑喷施时期的推移，各节间长度降低幅度减小，而节间直径则随着节间长度的减少逐渐增大，茎秆充实度明显提高。③随多效唑喷施时期的推移，茎秆各节间的弯曲力矩和倒伏指数渐增，抗折力渐减，抗倒性逐渐减弱，均在A1处理时最好。④穗颈方面，农大8号穗颈含水量、弯曲力矩有明显变化，其中，穗颈弯曲力矩在A1处理最小，穗颈含水量则在A2处理下最低。而张杂10号穗颈除弯曲力矩有影响外，其他指标无显著变化，其中，穗颈弯曲力矩在A1处理时达到最小。⑤影响谷子产量的关键构成是穗重及穗粒重，在A2处理下谷子增产显著，农大8号产量比CK增加7.10%，张杂10号产量比CK增加8.29%。因此，在拔节期喷施300 mg·L^-1多效唑，可提高谷子茎秆充实度，增强抗倒伏能力，增产效果最好。

Effects of Paclobutrazol on Stalk Characteristics and Lodging Resistance of Foxtail Millet

In order to study the effects of paclobutrazol on stalk traits and panicle neck lodging resistance of foxtail millet, this paper used a randomized block design, 300 mg·L^-1 paclobutrazol were sprayed on foxtail millet leaf at the stage before jointing (A1), jointing stage (A2) and booting stage (A3), which water was used as control (CK). Stalk characters, lodging index, panicle parameters and yield of millet were measured. The results were as followed. ① Compared with CK, the growth and development of millet plants were significantly inhibited. The earlier spraying period was, the more obvious inhibition effect was, and the lower plant height was. ② The plant heights of the two varieties were the minimum in A1 treatment, and the ratio between height of gravitational center and plant height had similar changing trend. The stem diameter of basal internode was increased and reached the maximum value in A1 treatment. With the advance of paclobutrazol spraying period, the decreasing range of internode length was smaller, and the internode diameter was gradually increased with the decrease of internode length, and the stalk plumpness was significantly improved. ③ With the advance of paclobutrazol spraying period, the bending moment and lodging index were increased gradually, the bending force was decreased, and lodging resistance was gradually decreased. All of them were best in A1 treatment. ④ In terms of panicle neck, the water content and bending moment of Nongda 8 had been obviously changed. Among them, the bending moment of panicle neck was the smallest in A1 treatment, while the water content of panicle neck was the lowest in A2 treatment. However, there was no significant change other indexes except the bending moment of panicle neck of Zhangza 10. Among them, the bending moment of panicle neck reached the minimum in A1 treatment. ⑤ The key components affecting the yield of millet were panicle weight and grain weight of panicle. In A2 treatment, yield was increased significantly. Compared with CK, the yields of Nongda 8 and Zhangza 10 were increased 7.10% and 8.29% higher, respectively. Therefore, the spraying of 300 mg·L^-1 paclobutrazol at the jointing stage could improve the stalk plumpness and enhance the lodging resistance. The effect of increasing yield was the best.