超高产大豆砧木对不同年代育成品种光合生理指标和产量性状的影响

【目的】研究以超高产大豆品种为砧木嫁接不同年代育成品种,旨在明确嫁接超高产品种的根系对接穗品种叶片生理指标的影响,从而揭示根系改良在大豆育种中的作用。【方法】以来自相同的祖先亲本(Williams和Amsoy)且地理纬度相同的美国俄亥俄州和中国辽宁省不同年代育成的11个代表性大豆品种为接穗,采用劈接法,于子叶期分别与超高产大豆品种辽豆14和中黄35的砧木进行嫁接,其中,以11个不同年代育成品种的自身嫁接处理与不嫁接处理作为对照。在盆栽条件下,于R1、R2、R4、R5、R6期测定植株叶片的光合速率、气孔导度、蒸腾速率和叶色值,于成熟期收获后对植株进行考种,测定植株的单株粒数、百粒重和单株产量。【结果】不同生育时期大豆品种的根系活力均表现为辽豆14中黄3511个不同年代育成品种,R5期和R6期达到显著或极显著差异水平。叶片的光合速率、气孔导度、蒸腾速率和叶色值均呈单峰曲线变化,其中,光合速率、气孔导度、蒸腾速率于R2期达到高峰值,叶色值于R4期达到高峰值,而后开始呈下降趋势。不同年代育成品种在不嫁接与自身嫁接条件下具有相似的变化曲线,而嫁接于超高产品种辽豆14和中黄35的砧木后,曲线下降较缓慢。R5至R6期间,嫁接于自身砧木上的植株其叶片的光合速率、气孔导度、蒸腾速率和叶色值平均每天分别下降1.43%、3.67%、3.38%和0.82%,而嫁接于超高产品种砧木上的植株相应下降了1.11%、3.26%、2.05%和0.48%。不同年代育成品种在自身嫁接与不嫁接条件下,其单株粒数、百粒重、单株粒重无显著变化,而与自身作砧木的植株相比,嫁接到超高产品种辽豆14或中黄35砧木上后,其单株粒数、百粒重和单株产量分别提高了2.82%、9.36%和10.60%,且当代品种的增幅要大于中期品种和共同亲本。【结论】超高产品种辽豆14和中黄35根系在生殖生长期具有较高的生理活性。嫁接超高产品种砧木可以有效减缓不同年代大豆品种生育后期的叶片光合速率、气孔导度、蒸腾速率和叶色值的下降速率,增强植株的光合能力,进而提高产量。因此,在未来大豆育种工作中,应该更加注重根系的遗传改良。

Effects of Super-High-Yield Soybean Cultivars as Rootstock on Some Physiological and Yield Traits of Cultivars Released in Different Decades

【Objective】 The objective of this study is to determine the effects of super-high-yield soybean cultivars as rootstocks on some physiological traits of cultivars released in different decades, in order to reveal the important role of root improvement in soybean breeding. 【Method】 The 11 cultivars released in different decades by Liaoning, China and Ohio, USA, having the common ancestors Amsoy and Williams, were used to graft onto the rootstocks of super-high-yield cultivars Liaodou 14 and Zhonghuang 35 by cleft grafting method at cotyledon stage, respectively. The 11 cultivars released in different decades treated with self-grafting and non-grafting were used as the control. Under the conditions of pot experiment, the photosynthetic rate, stomatal conductance, transpiration rate and leaf greenness values were determined at R1, R2, R4, R5, and R6 stages, the seeds per plant, 100-seed weight, seed weight per plant were determined at mature stage and after harvest to test the plants. 【Result】 The root vigor of soybean cultivars at different growth stages were characterized by Liaodou 14 ＞ Zhonghuang 35 ＞ 11 cultivars released in different decades, at R5 and R6 were at significant or extremely significant level. The photosynthetic rate, stomatal conductance, transpiration rate and leaf greenness values showed a single peak curve in the whole growth stages. The photosynthetic rate, stomatal conductance, transpiration rate reached peak value at R2 stage, and the leaf greenness values reached peak value at R4 stage, and then began to decline. Cultivars released in different decades had similar curves between non-grafted and self-grafted plants. However, the decline of the curve became slower after being grafted onto the rootstocks of super-high-yield cultivars Liaodou 14 and Zhonghuang 35 than that of self-grafted plants. At R5 to R6 stages, the daily decrease rates of non-grafted and self-grafted plants for photosynthetic rate, stomatal conductance, transpiration rate and leaf greenness were by 1.43%, 3.67%, 3.38% and 0.82%, respectively, but those of cultivars grafted onto Liaodou 14 and Zhonghuang 35 rootstocks were by 1.11%, 3.26%, 2.05% and 0.48%, respectively. The seeds per plant, 100-seed weight, seed weight per plant of cultivars released in different decades had no significant difference between self-grafted and non-grafted plants. At mature stage, the seeds per plant, 100-seed weight and yield per plant of cultivars released in different decades were increased significantly as grafted them onto super-high-yield cultivars Liaodou 14 or Zhonghuang 35 as rootstocks, by 2.82%, 9.36% and 10.60%, respectively, and the increase of current cultivars was greater than middle cultivars and common parents. 【Conclusion】 The roots of super-high-yield cultivars Liaodou 14 and Zhonghuang 35 have higher physiological activity at reproductive stage. Cultivars grafted onto the rootstock of super-high-yield cultivar could reduce significantly the rate of decline in photosynthetic rate, stomatal conductance, transpiration rate and leaf greenness value, and improve the photosynthetic ability, and thus increasing grain yield. Therefore, more attention should be pay to the genetic improvement of root in the future breeding work.