水分亏缺冬小麦近等基因系冠气温差与群体总耗水量的关系

Canopy-air temperature difference of winter wheat near-isogenic lines and its relationship with total water consumption by winter wheat grown under water deficit conditions

研究品种之间群体耗水特性的差异及其关键影响因素,为品种耗水特性评价与低耗水品种鉴选方法提供依据。选用水分亏缺条件下产量差异不显著,但耗水量差异极显著的冬小麦品种晋麦47和京411及其15个近等基因系为实验材料。利用防雨池和防雨棚开展实验,模拟水分亏缺条件。监测全生育期土壤水分含量,计算总耗水量,收获后测定籽粒产量,计算水分利用效率(WUE)。同时,分别在拔节-孕穗期、抽穗-开花期和灌浆期3个不同生育期监测冠层-大气温度差值(CTD)、叶片蒸腾速率和气孔导度。结果表明,3个不同生育期,15个近等基因系及其亲本之间,CTD均达到显著差异。CTD的方差分析表明,基因型和年份均对不同生育期的CTD有显著影响,但是二者之间仅在抽穗-开花期存在互作(P=0.0002)。15个近等基因系及其亲本之间耗水量存在显著差异,产量没有显著差异。源于耗水量的差异,部分品种/系之间WUE达显著差异。3个不同生育期,15个近等基因系及其亲本之间,CTD与总耗水量均呈极显著负相关关系。抽穗-开花期最高,2012—2013年度和2016—2017年度分别达到0.7042和0.6095。叶片蒸腾速率和气孔导度与群体总耗水量之间相关性很弱,3个生育期均未达到显著水平。对该组近等基因系材料,影响群体总耗水量的关键因素不是叶片蒸腾生理特性,而是群体冠层生长特性。表明构建合理的群体冠层结构不仅是获得高产的途经,而且是调控群体总耗水量,提高品种水分利用效率的重要途径。

This study explored the key factors that lead to differences in water consumption among different populations with different genotypes, to evaluate genotype-specific water consumption traits and select ideal varieties with low water requirements. Fifteen near-isogenic lines( NILs),along with their donor parent Jing 411 and recurrent parent Jinmai 47,were used as materials in this experiment. The materials tested have significantly different water consumptions,but there areno significant differences in their yields under water deficit conditions. Automatic rain-shelter and rain-proof pools that can prevent water seepage were used for the simulated water deficit treatment. The soil water content of all the genotypes were monitored over the whole experimental period and the total water consumption was calculated using the water balance equation. Grain yield was measured after harvest and then the water use efficiency( WUE) was calculated. The canopy-air temperature difference( CTD),leaf transpiration rate,and stomatal conductance were also monitored at the jointingbooting,heading-flowering,and grain-filling stages. The results indicated that the 15 NILs,along with their parents,had significantly different CTDs during all three growth periods. Analysis of variance for the CTD differences indicated that genotype,and growth and development year significantly affected CTD,but there was an interaction between the two factors only at the heading-flowering stage( P = 0.0002). There were significant differences in water consumption among the 15 NILs and their parents. However,there were no significant differences in yield. The differences in water assumption meant that there were significant differences in WUE among some genotypes. The CTDs at all three growth and development stages negatively correlated with water consumption. The R2 value was the highest at the heading-flowering stage,and was 0.7042 and 0. 6095 during 2012-2013 and 2016-2017,respectively. The correlations between leaf transpiration rate,and stomatal conductance and water consumption were very weak among the 15 NILs and their parents. The correlations were not significant for any of the three growth and development stages. The results for the near-isogenic lines tentatively indicate that under water deficit conditions,the canopy structure traits,rather than leaf gas exchange properties such as leaf transpiration rate and stomatal conductance,significantly affect population-specific water consumption. The results also show that establishing a suitable population canopy structure increases yields and can control water consumption,which leads to an improvement in WUE.