紫花苜蓿物候期与热量条件的关系

Relationship between phonological phase and thermal conditions for alfalfa

【目的】研究紫花苜蓿物候期与气象条件的关系,为紫花苜蓿的高产栽培和育种提供参考。【方法】采用有效积温法探讨了紫花苜蓿各生育阶段的下限温度,利用各生育阶段和各茬次的热量指标分析了7个不同秋眠性紫花苜蓿品种物候期热量条件的变化规律。【结果】(1)秋眠性苜蓿品种巨人201返青晚、开花晚、对温度要求较高;非秋眠性品种超级13R返青早、开花早、对温度要求较低;半秋眠性品种路宝、美国杂交熊、牧歌104和超级阿波罗居中。(2)紫花苜蓿从返青到分枝、从分枝到现蕾、从现蕾到开花、从开花到结荚的温度下限分别为(5.68±0.61),(13.95±1.78),(17.37±2.99)和(21.83±0.95)℃。(3)2004年紫花苜蓿一年刈割了4茬,前3茬在开花期刈割,第4茬在分枝末期刈割。全年刈草≥5℃总有效积温为4 570.91(d.℃),间隔时间236.57 d。其中,第1茬苜蓿从返青到刈草≥5℃的有效积温平均为1 036.21(d.℃),间隔时间为75.57 d;第2茬苜蓿需≥5℃的有效积温平均为1 163.80(d.℃),间隔时间为50 d;第3茬苜蓿需≥5℃的有效积温平均为1 515.50(d.℃),间隔时间为61 d;第4茬苜蓿需≥5℃的有效积温平均为855.40(d.℃),间隔时间为50 d。【结论】气温和紫花苜蓿的物候期关系密切,只有气温≥紫花苜蓿某一发育阶段要求的温度下限值,并且有完成该生育阶段所要求的≥5℃有效积温时,紫花苜蓿才能够顺利地完成该生长阶段的发育过程而进入下一生育阶段。

【Objective】Relationship between phonological phase and thermal conditions of alfalfa was exposed to offer reference for high-yielding cultivation and breeding practices of alfalfa.【Method】Lower limit temperature of different growth phases in alfalfa was discussed by effective accumulated temperature method,also,change rule of thermal condition of different phonological phases for seven alfalfa varieties was analyzed by thermal index in different growth phases and different cuttings.【Result】（1）Fall dormancy cultivar,Ameristand201 revived and flowered late,required high average temperature.Semi-fall dormancy cultivar such as Lobo,Meiguozajiao,Amerigraze401 and Apollo supreme were second.Non-fall dormancy cultivar 13Rsupreme revived and flowered early,required low average temperature.（2）For alfalfa,from reviving to branching period,branching to budding period,budding to efflorescence period,and efflorescence to pudding period,lower limit temperature was respectively（5.68±0.61）,（13.95±1.78）,（17.37±2.99）,（21.83±0.95）℃.（3） Alfalfa was harvested three times a year in efflorescence period,and the fourth cutting was harvested in branching later period in 2004.Interval days and effective accumulated temperature above 5 ℃ were respectively 236.57 days and 4 570.9 1（d·℃） from reviving period to the last cutting in a year,75.57 days and 1 036.21（d·℃） for the first growth season,50 days and 1 163.80（d·℃） for the second growth season,61 days and 1 515.50（d·℃） for the third growth season,50 days and 855.40（d·℃） for the forth growth season.【Conclusion】Temperature and phonological phase were closely related.Alfalfa can not accomplish some growth stage and enter the next one,until temperature is up to the lowest limitation with accumulated temperature for some growth stage.