| Wheat is one of the important food crops in China,and its yield and quality play a vital role in the quality of people’s life and national food security.With the shortage of water resources,drought has gradually become one of the important factors limiting wheat production and affecting its quality.Studies have shown that heterologous goat grass is an important germplasm resource for genetic improvement of wheat,and its cytoplasm directly affects the stress tolerance and quality of wheat.In this paper,10 homogeneous heterogeneous wheat strains of Goatgrass were used as materials,and by analyzing various physiological indexes of heterogeneous wheat seedling stage under PEG-6000 simulated drought stress,the cytoplasm of Goat grass with excellent drought resistance was screened,which provided a theoretical basis and drought-resistant germplasm for wheat drought-resistant breeding,and at the same time explored the differences in grain starch characteristics,dough characteristics and baking quality of 10 homogeneous heterogeneous wheat under rainfed and irrigated conditions,which laid the foundation for further utilization of heterologous goat grass germplasm for wheat quality improvement.The main results are as follows:1.PEG-6000 simulated drought stress had a significant effect on the germination of homonuclear heterogeneous wheat,and the fresh weight,dry weight,relative water content,total root volume,total root surface area,total root length and plant height decreased after drought stress at the seedling stage,but the germination and growth indexes were significantly different between cytoplasms.The aerial morphology and root indexes of Aegilops tauschiiChris,Aegilops uniaristata-Chris,and Aegilops longissima-Chris performed well after drought stress,and the germination indicators performed relatively well.Wheat under the cytoplasmic background of Aegilops tauschii,Aegilops uniaristata,and Aegilops longissima could better maintain root morphology under stress,improve water absorption capacity and maintain aboveground growth,indicating that it has strong adaptability to arid environment.2.The MDA content,antioxidant enzyme activity,soluble sugar content,free proline content and chlorophyll content of 10 kinds of homonuclear heterogeneous wheat under PEG-6000 simulated drought stress were compared,and the results showed that drought stress increased the physiological indexes of homonuclear heterogeneous wheat to varying degrees.Under drought stress,Aegilops longissima-Chris showed large increase in antioxidant enzyme activity,small increase in MDA content and accumulation of osmoregulatory substances,and also performed well in wheat plant growth indexes and morphological indicators,indicating that the cytoplasm of Aegilops longissima had a positive effect on drought resistance at the seedling stage of wheat.In contrast,wheat against the cytoplasmic background of Aegilops cylindrica and Aegilops crassa showed weak drought resistance.3.Compared with the traits under irrigation,the plant height,panicle length,number of ears per plant and yield of 10 heterogeneous wheat materials were reduced under rain-fed conditions,and the ear length and 1,000-grain weight were less affected by rain-fed conditions.Under rain-fed conditions,Aegilops longissima-Chris performed better in yield traits,while Aegilops cylindrica-Chris and Aegilops crassa-Chris,on the contrary,showed that the cytoplasm of Aegilops longissima had significant advantages in resisting yield reduction under rain-fed conditions,and showed better drought resistance corresponding to the drought resistance index at seedling stage.The correlation analysis of ear traits under rain rearing showed that the number of ears,the number of ear grains and the drought resistance performance of each plant were positively correlated with the yield,while the plant height showed a negative correlation.The results showed that spikelet number,ear number and plant height were important factors determining the yield and drought tolerance of homogeneous wheat.4.Under rainfed conditions,the protein content,wet gluten content,sedimentation value and amylose content of 10 homonuclear heterogeneous wheat grains were reduced,and the number of B-type starch grains was increased.The grain quality of Aegilops tauschii-Chris and Aegilops bicornis-Chris was better and the number of amylose grains decreased less than that of irrigation,and the number of B-type starch grains of Aegilops bicornis-Chris and Aegilops kotschyi-Chris increased more.Compared with the irrigation conditions,the dough mixing characteristics under the cytoplasmic background of Aegilops bicornis,Aegilops longissima and Aegilops variabilis were better under rainfed conditions,and the dough stabilization time and formation time of these three cytoplasmic backgrounds were longer,indicating that the three cytoplasmic heterogeneous wheat were more resistant to kneading and had better dough quality under rain-fed conditions.5.Under rainfed conditions and irrigation conditions,the characteristics of four different qualities of homonuclear heterogeneous wheat flour bread were analyzed and it was found that the phenotype and texture of bread changed to varying degrees.The bread made from homonuclear heterogeneous wheat flour under rain-fed conditions had a larger specific volume and volume and a better overall score.Aegilops kotschyi-Chris showed considerable sensory evaluation and bread appearance under rain-fed conditions,while the opposite was true for Aegilops cylindrica-Chris under irrigation and rainfed conditions.In summary,wheat under the cytoplasmic background of Aegilops longissima showed strong drought resistance at the seedling and ripening stages,and the bread made from wheat flour under dry farming conditions had better dough quality and taste. |
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