Effects Of Exogenous Plant Growth Regulators On Wheat Processing Quality

Wheat(Triticum aestivum L.)is one of the most widely distributed,the biggest in area,the largest amount of trade,the highest nutritional value of food crops worldwide.China is the largest wheat producer and consumer.In China,there are many wheat varieties with pretty high yield but poor processing quality.The improvement of processing quality has become an increasingly prominent problem.Plant growth regulators play an important role in the formation of wheat processing quality.To investigate the effects of the plant growth regulators on processing quality of wheat and to provide basic knowledge for quality breeding,3 wheat lines(Roblin,Shumai 482 and Qc)were selected and planted in experimental farm in Wenjiang,Sichuan Agricultural University.Abscisic acid,cytokinin,ethephon,auxin,methyl jasmonate,salicylic acid,gibberellin and gibberellin inhibitors uniconazole were sprayed once a week at 5:00 pm for five continuous times,and water was sprayed as control.The hormones were firstly sprayed on the 7th day after flowering.The protein content,wet gluten content,sedimentation value,mixograph parameters,farinograph parameters and the content of starch were tested.The main results were summarized as follows:1.After external application of abscisic acid,cytokinin,ethephon,auxin,methyl jasmonate and salicylic acid,bulk density,1000-grain weight and gluten index decreased,but the difference was not significant;Protein content,sedimentation value,wet gluten content,dry gluten content increased,but the difference was not significant;Falling number decreased and the difference was not significant,however,with the peak time,width,8 min width as the representative of the mixograph parameters and the formation time,water absorption rate,stable time as the representative of the farinograph parameters did not change significantly or show a clear trend of change.The viscosity,breakdown,setback,peak time and pasting temperature of Shumai 482 and Qc decreased,but the pasting parameters of Roblin improved.The results of variance analysis showed that the genotype had the greatest influence on wheat processing quality parameters and pasting characteristics,followed by plant growth regulators,and genotype × plant growth regulators had minimal impact.2.After spraying gibberellin,protein content,sedimentation value,wet gluten content,dry gluten content,gluten index decreased,but the difference was not significant;Falling number decreased.significantly,the viscosity,breakdown and setback of pasting parameters properties decreased significantly.However,the above parameters showed the opposite trend after exogenous spraying uniconazole.The mixograph parameters and the farinograph parameters were closely related to meterials.Exogenous application of gibberellin,uniconazole could reduce the enzyme activity of granule-bound starch synthase(GBSS)during grain filling,soluble starch synthase(SSS)during the later period of filling,and reduce the content of total starch,amylose and amylopectin.Spraying gibberellin could make the amylose/amylopectin ratio of Shumai 482 increase,meanwhile,spraying uniconazole could make the amylose/amylopectin ratio of Roblin reduce.The results of variance analysis showed that the genotype had the greatest influence on wheat processing quality parameters,however,the plant growth regulators had the greatest influence on pasting characteristics.