倒春寒发生时期和次数对冬小麦产量性状的影响

为了解倒春寒发生时期和次数对冬小麦产量性状的影响,以45个冬小麦品种(系)为材料,室内模拟倒春寒的发生,调查和分析不同倒春寒处理后冬小麦株高、有效穗数、生物产量、籽粒产量等性状的变化.结果表明,随着低温处理时间的推迟和次数的增加,抽穗期均值相应递延1d.早期(3月初即拔节期)和晚期(4月初即孕穗期)发生的倒春寒都会造成产量不同程度下降,以早期倒春寒影响更为严重,产量降幅达19.9％,而晚期倒春寒使产量降低8.9％.发生两次倒春寒时减产效应累加,产量分别较对照、早期倒春寒和晚期倒春寒降低28.3％、10.6％和21.4％.早期倒春寒的减产作用主要是因为穗数降低,而晚期倒春寒主要是因为穗粒数降低.周麦23号由于其春季晚发快长特性,受倒春寒的影响较小.因此,在新品种选育时,应注意减少选择冬季表现为半冬性、而春季表现为早发快长的弱冬性品系,以减轻倒春寒的危害.

Effect of Different Periods and Frequency of Late Spring Coldness on Winter Wheat Yield Related Traits

In order to understand the influence of late spring coldness period and frequency of occurrence on yield of winter wheat,simulating the time and frequency of occurrence of unusually coldness in early spring were conducted on 45 winter wheat cultivars(lines).The results showed that with the extension of time and increase of frequency under low temperature treatment,heading stage averagely deferred 1 d.Early or later of late spring coldness had various degrees impact on wheat yield,but the early frost damage was more serious than late frost damage.Wheat yield decreased by 19.9% when the early frost damage happened and reduced by 8.9% when late spring coldness happened.Wheat yield was the lowest when frost damage occurred twice,and the degree affected by freezing showed the cumulative effects.The effects made wheat yield further reduced significantly.Yield reduced by 28.3%,10.6% and 21.4% when frost damage occurred twice compared with the control,early late spring coldness and later late spring coldness occurred once.Early frost damage mainly decrease yield by reducing ear number,while late frost damage mainly affected yield by decreasing grain number per spike.Zhoumai 23 was affected less by coldness in early spring due to its characteristics.Attention should be given to reduce the choice of the performance of semi-winter habit in winter,and weak winter habit in spring to reduce the damage when unusually coldness in early spring occurres.