不同土壤水分下大豆根冠互作对产量和农艺性状的影响

为明确不同土壤水分下大豆根冠互作对产量和农艺性状的影响,为大豆抗旱育种提供理论依据,利用耐旱型品种辽豆14与干旱敏感型品种辽豆21进行相互嫁接,在结荚期设置正常供水(80%田间持水量)和水分胁迫(50%田间持水量,持续20 d)处理,成熟期测定主要农艺性状。试验结果表明,大豆地上部农艺性状和产量主要由地上部基因型决定,但水分胁迫下也会受到根系基因型的影响。正常供水与水分胁迫下,与辽豆21相比,辽豆14接穗的株高平均提高24.3%和14.8%,主茎节数分别平均提高19.6%和15.3%,分枝数分别平均提高60.2%和90.6%,单株生物量平均提高57.1%和87.1%,单株荚数平均提高70.0%和92.3%,分枝荚数平均提高159.9%和197.9%,分枝瘪荚率平均降低57.8%和60.4%,最终单株粒重平均提高19.9%和54.9%。与辽豆21自身嫁接植株相比,水分胁迫下,嫁接辽豆14砧木使单株荚重、单株荚数、单株粒数、百粒重和单株粒重分别显著提高了45.8%、27.4%、21.7%、5.2%和20.4%,产量性状的提高与主茎第9～15节位间有效荚数的提高有关。因此,通过地上部与根系的协同改良是提高大豆抗旱性的重要途径。

Effects of root|shoot interaction on yield and agronomic traits of soybean under different soil moisture conditions

The purpose of this study was to determine the effects of soybean root|shoot interaction on yield and agronomic traits under different soil moisture conditions, thus provide theoretical basis for drought resistant soybean breeding. Grafted plants of drought|tolerant cultivar Liaodou 14 and drought|sensitive cultivar Liaodou 21 grew in the pot|culture experiments. Well|watered (80% of field water holding capacity) and water stress (50% of field water holding capacity, lasting for 20 days) were conducted during podding stage, and the agronomic traits were measured at maturity. The results showed that the agronomic traits and yield of soybean were mainly determined by the shoot genotype, but were also affected by the root genotype under water stress. Compared to Liaodou 21 scion, Liaodou 14 scion had averaged increases of 24.3% and 14.8% in plant height, 19.6% and 15.3% in main stem node number, 60.2% and 90.6% in number of branches, 57.1% and 87.1% in biomass, 70.0% and 92.3% in number of pod per plant, and 159.9% and 197.9% in number of pod on branch; it also had averaged decreases of 57.8% and 60.4% in flat pods rates on branch, and increases of 19.9% and 54.9% in grain yield under both well|watered and water stress conditions, respectively. Under water stress, grafting Liaodou 21 scion onto Liaodou14 root stock resulted in significant increases in pod weight per plant, number of pods per plant, number of seeds per plant, 100|seed mass, and grain yield per plant by 45.8%, 27.4%, 21.7%, 5.2%, and 20.4%, respectively, which was attributed to greater available number of pods on 9~15th nodes on stem, as compared to its self|grafts. Our results suggested that the cooperative improvement between shoot and root would be an important way to improve the drought resistance of soybean.