Screening And Identification Of Early Maturity Mutants Induced By EMS In Processing Tomato

In Xinjiang,tomato processing is a unique horticultural industry,with the largst production and processing scale in the country.Xinjiang has a short frost-free period,resulting in a concentrated supply period of processed tomato raw materials and a short full-load operation time for processing equipment.Therefore,a reasonable mix of early,mid-and late-maturing varieties is required in production to extend the supply period of raw materials and achieve the purpose of a balanced supply.In the breeding of new varieties,due to the lack of early-maturing germplasm resources and the difficulty of genetic selection,there are fewer early-maturing varieties popularized in production.At present,cultivating early-maturing varieties has been an important goal for the selection and breeding of new varieties of processing tomato,and it has also become one of the main tasks for the selection and breeding of new varieties.Therefore,this article uses EMS mutagenesis to obtain early-maturing mutants as experimental materials,and studies the phenological period,agronomic traits,photosynthetic characteristics,and quality indicators of the mutants,and uses transcriptomics methods to molecularly analyze the flowers and fruits of the mutants.Horizontal research,to explore the mechanism of early maturity of mutants from physiological to molecular level,provides a certain reference and theoretical basis for the breeding of early-maturing varieties..The results of the study are as following:1.Investigations on the phenological period and agronomic traits of the early-maturing mutants of processing tomato showed that the early-maturing mutants had a low initial flower node,and the budding and flowering periods were earlier than the original parents.Therefore,the budding period,flowering period and initial flower node position which can be used as the basis to judge the early maturing varieties.From the perspective of various agronomic traits,the early-maturing mutants TH11-2 and TH12-7 performed the best.The number of first and second ears and the early yield were significantly higher than those of the original parent,but the weight of each fruit was smaller than that of the original parent.There was no significant difference in the control group.It can be seen that the single fruit weight has a significant negative correlation with the number of ears and two ears.Therefore,early maturity and single fruit weight should be considered in the selection process of early maturing varieties to obtain the best varieties.The study of leaf chlorophyll content and photosynthetic characteristics of early-maturing mutant materials found that the chlorophyll content and photosynthesis of the same variety showed a low-high-low trend as the growth period progressed;the changes between different varieties are different,and the current The chlorophyll content of the early-maturing mutants TH11-2 and TH12-7 was significantly higher than that of the original parent at the bud stage,flowering stage and fruit setting stage,increasing by 8.52%,8.88%,9.87% and respectively.9.43%,8.58%,3.47%;the photosynthesis changes,TH11-2 in the fruit setting stage,the transpiration rate,net photosynthetic rate and stomata.The conductance was significantly higher than that of the control Rigel 87-5;the net photosynthetic rate of TH12-7 in the budding and flowering stages was significantly higher than that of the control,Increased by 16.4% and 13.6% respectively,indicating that the chlorophyll content and photosynthetic capacity of the leaves of the early-maturing varieties were higher in the bud,anthesis and fruiting stage.2.The results showed that the contents of total sugar,lycopene,sugar-to-acid ratio and solid-to-acid ratio in the early maturity mutant TH11-2,significantly increased.The content of total acid and ascorbic acid decreased significantly,fruit firmness and soluble solid content no significant difference.Fruit firmness,soluble solids,total acid and ascorbic acid content of TY11-1 fruit were significantly lower than those of control.The contents of total sugar and lycopene in TH12-7 fruit were significantly higher than those in the control,Increased by10.95% and 21.65% respectively,and the ratio of sugar-acid was significantly lower.There were no significant differences in total acid,soluble solids,fruit firmness and the ratio of solid-acid from those of the original parent;Lycopene,soluble solids,fruit firmness and ascorbic acid content of TH12-6 were significantly lower than the control.On the whole,the precocious mutant Th11-2 was superior to Th12-7 and Ty11-1 to Th12-6.These results indicated that the traits of mutant Th11-2 and Th12-7 were superior to those of the control,and their agronomic traits and quality indexes met the requirements of early maturing varieties.3.Using transcriptional methods to study the precocious mechanism of the precocious mutants.The results showed that the J gene,which regulates flowering,the DDTFR18 gene,the MADS-box family genes FUL1,FUL2,TAGL1,SOC1,AGL24,and the main gene GA2ox1 for gibberellin synthesis,GA2ox2,flower-promoting factor gene FPF1 were all up-regulated in the mutant,while the ethylene receptor and ethylene response factor-related genes in the mature fruit of the early-maturing mutant were down-regulated,thereby negatively regulating the ripening of the fruit.