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美国北部大平原种植的春小麦的籽粒灌浆期恰与干旱和高温胁迫时期相遇,这往往降低作物的产量和品质。在北达科他州四种旱作环境中测定了20个春小麦基因型,用以评价籽粒灌浆速度和持续期的基因型变异,并且考查了开花后干旱和高温胁迫对估计籽粒灌浆参数、环境限制因素、小麦生产力和环境容许的胁迫耐力间的关系。用一个二次多项式来描述籽粒重量和从开花至成熟期间累积的生长度-日之间的关系。根据拟合曲线估算籽粒灌浆速度和灌浆持续期。各基因型的籽粒灌浆速度和持续期都不相同,但在灌浆期间增温,使籽粒过早地趋于停止生长,并加速生理成熟。籽粒灌浆速度与粒重相关,而不是持续期与粒重相关。在本试验环境条件下,靠延长籽粒灌浆期来增加籽粒重量,看来并不是增加籽粒产量的一个有效途径。因为本试验基因型中,籽粒灌浆的速度和持续期无必然联系,所以本试验认为,不需要延长籽粒灌浆持续期只要同时选择高灌浆速度和高籽粒重量便可能获取高籽粒产量;并认为通过高籽粒重量来选择高籽粒灌浆速度也是可能的。在本试验的基因型中,似乎籽粒灌浆的高速度与短持续期有助于增加对胁迫的耐力,但在研究的20个基因型中只有一个具备两种特性。在生育期常因严重胁迫而缩短的环境中,高籽粒灌浆速度和短到中等长度的持续期看来是较为理想的。
Spring wheat grown in the northern Great Plains of the United States, just before drought and during high temperature stress, tends to have a lower grain yield and quality during grain filling. Twenty spring wheat genotypes were assayed in four dry-farming environments in North Dakota to assess genotypic variation of grain filling rate and duration, and the effects of drought and high temperature stresses on grain filling parameters, environmental limiting factors , The relationship between wheat productivity and environmental tolerance stress endurance. A quadratic polynomial is used to describe the relationship between grain weight and the degree of growth accrued during flowering to maturity - day. Estimation of grain filling rate and filling duration based on fitted curve. The grain filling rates and durations of all genotypes were different, but the temperature was increased during filling, which prematurely stopped the growth of the grain and accelerated the physiological maturation. Grain filling rate was related to grain weight, not duration, to grain weight. Under this experimental environment, increasing grain weight by prolonging grain filling does not appear to be an effective way to increase grain yield. Because the speed and duration of grain filling were not necessarily related to the duration of the grain filling in this experiment, we concluded that high grain yield could be achieved without the need of prolonging the grain filling duration as long as both high filling speed and high grain weight were selected; It is also possible to select high grain filling rates with high grain weights. In the genotypes of this experiment, it seems that high speed and short duration of grain filling help to increase endurance to stress, but only one of the 20 genotypes studied has both characteristics. In environments where growth is often shortened due to severe stress, high grain filling rates and short to medium duration durations appear to be ideal.