Screening Of High Carotenoid Germplasm Resources Of Spinach And Analysis Of Combining Ability Of F₁ Generation

Spinach is rich in nutrients and minerals and is loved by vegetable growers and consumers.Spinach is the leafy green vegetables with the highest carotenoid content,which is of positive significance to human health.With the improvement of people's health awareness,the research on carotenoids in spinach and the breeding of varieties with high nutritional quality have become an important breeding direction.However,there are few studies on the evaluation and utilization of different germplasm resources of carotenoids in spinach,and the accumulation of carotenoids in spinach,and the breeding and application of high-quality varieties with high accumulation of carotenoids are also scarce.In this experiment to spinach's collection of 151germplasm resources for materials at home and abroad,through the analysis of the measuring and carotenoid content,select the high carotenoid accumulation germplasm material,and build the F₁ generation of carotenoids related groups,select the excellent cross combinations,spinach for carotenoid accumulation pattern research lay the foundation.The main results are as follows:1.The carotenoid content of 151 germplasm resources collected ranged from 2.1mg to 4.5 mg per gram of dry weight,and the carotenoid content of materials was in line with normal distribution,with an average of 3.3 mg per gram of dry weight.Among them,the spinach material US216-9 introduced from France had the lowest carotenoid content,and the spinach material US355-4 introduced from United States region had the highest carotenoid content.These germplasm with rich difference in carotenoid content laid the material foundation for the breeding of spinach with high carotenoid content.2.Thirty-two hybrid combinations were prepared,and the biological characters,downy mildew resistance and carotenoid content of 10 F₁ populations crossed from wild and cultivated species of spinach were investigated.The results showed that the leaves of 10 combinations had round and different degrees of halberd leaves,which were different from those of the parents.Compared with the green and light green leaf colors of the parents,the 10 combinations had abundant leaf colors,which were divided into dark green,green,light green and yellow-green,the differentiation of leaf color of F1 generation population was diverse.The chlorophyll content of F₁generation spinach ranged from 24.57 SPAD to 62.03 SPAD,with an average value of40.28 SPAD.The average value,minimum value and maximum value of chlorophyll content in F₁ generation of US357-1-10×SP73 were 37.34 SPAD,27.87 SPAD and46.77 SPAD respectively.The average value of chlorophyll content in F₁ generation of US362-5×SP73 was 48.87 SPAD,the minimum was 32.73 SPAD,and the maximum was 62.03 SPAD.In addition,leaf color is related to carotenoid content and chlorophyll content,but the change rule of carotenoid content and chlorophyll content is not clear.3.By analyzing the general combining ability(GCA)of carotenoid content of six parent materials,it was clear that SP73 was suitable to be the female parent in the cross combination,and US359-6,US357-1-10 and US357-1-12 were suitable to be the male parent in the cross combination.The results showed that SP73×US357-1-12,SP73×US357-1-10 and SP73×US359-6 had higher special combining ability effect on carotenoid content.In the 10 cross combinations,the positive advantage of carotenoid content in ultra-low parental dominance was 30%,and the positive advantage in ultra-high parental dominance and ultra-medium dominance was negative,indicating that there was no heterosis in carotenoid content in the 10 cross combinations.In addition,through the relative heritability analysis,it was found that the genetic characteristics of spinach carotenoids were more complex,and the probability of variation was larger.4.Carotenoid content of F₁ generation was investigated.The carotenoid content of SP73×US359-6 ranged from 1.4 mg to 3.3 mg per gram dry weight,with an average of 2.3 mg per gram dry weight.The carotenoid content of SP73×US357-1-10ranged from 1.6 mg to 3.3 mg per gram dry weight,with an average of 2.6 mg per gram dry weight.The carotenoid content of SP73×US362-5 ranged from 1.4 mg to3.3 mg per gram dry weight,with an average of 2.1 mg per gram dry weight.The carotenoid content of SP73×US358-9 ranged from 1.2 mg to 3.2 mg per gram dry weight,with an average of 2.1 mg per gram dry weight.The carotenoid content of SP73×US357-1-12 ranged from 1.8 mg to 3.1 mg per gram dry weight,with an average of 2.7 mg per gram dry weight.The carotenoid content of US359-6×SP73ranged from 1.7 mg to 2.5 mg per gram dry weight,with an average of 2.0 mg per gram dry weight.The carotenoid content of US357-1-10×SP73 ranged from 1.1 mg to3.1 mg per gram dry weight,with an average of 2.1 mg per gram dry weight.The carotenoid content of US362-5×SP73 ranged from 1.4 mg to 2.9 mg per gram dry weight,with an average of 2.2 mg per gram dry weight.The carotenoid content of US358-9×SP73 ranged from 1.4 mg to 3.1 mg per gram dry weight,with an average of 2.2 mg per gram dry weight.The carotenoid content of US357-1-12×SP73 ranged from 1.4 mg to 2.9 mg per gram dry weight,with an average of 2.0 mg per gram dry weight.The results showed that the carotenoid content of F₁ material with inbred line as female parent was higher than that of F₁ material with inbred line as male parent.The results showed that the content of carotenoids in spinach was affected by cytoplasmic genes.There was a significant positive correlation between carotenoid content and chlorophyll content,which indicated that chlorophyll content could be used as an auxiliary index for screening carotenoids in spinach.5.The investigation on downy mildew resistance of F₁ material showed that SP73×US358-9 had the lowest downy mildew resistance and SP73×US357-1-12 had the highest downy mildew resistance.There was a significant positive correlation between downy mildew resistance and carotenoid content and chlorophyll content,suggesting that carotenoid content and chlorophyll content of spinach might promote the improvement of downy mildew resistance of spinach.