| Caixin(Brassica campestris L.ssp.chinensis var.utilis Tsen et Lee,2n=20=AA)or flowering Chinese cabbage,also known as Tsai-tai,is rich in the content of amino acids and mineral elements,which is an important vegetable in southern China.It not only tastes delicious but also has many health care functions for people.So far,researchers mainly aimed to study the yield and plant resistance,but they paid much less attention to the nutritional quality,especially the content of mineral elements.In this study,six cytoplasmic male sterility lines and six inbred lines of Caixin were used as plant materials,and twenty-one cross combinations were made by incomplete diallel cross.In order to obtain excellent cross combinations,heterosis and correlation were analyzed by determining agronomic traits containing plant height,plant width and weight of main flower stalk,quality traits such as the content of vitamin C and mineral elements which including Ca,Mg,Na,Fe,Mn,Zn.Furthermore,according to measuring the contents of mineral elements in different parts of Caixin during the whole growing period,we analyzed the relationship of mineral element contents among stem,root and leaf,and the effect of different maturity on mineral element contents.Based on the analysis above,the main results were as follows:1.Caixin is rich in the contents of Ca,Mg,Fe,Zn.The highest value(dry weight)of the contents of Ca and Mg in Caixin were higher when compared with pakchoi cabbage and cauliflower,the content of Zn was higher than pakchoi,cauliflower and rape,and Fe in Caixin were higher than cauliflower.Hence,Caixin had considerable nutritional value.Besides,in all female parents,CX-b contained the highest contents of Ca,Mg,Fe,Zn,CX-a contained the highest content of Na,CX-e contained the highest content of Mn.The ratio of the maximum value to the minimum value was from 2.415 to 3.111.In all male parents,15-2 contained the highest content of Ca,Zn,15-1 contained the highest content of Mg,15-3 contained the highest content of Na,15-4 contained the highest content of Mn,the ratios of the maximum to the minimum were from 1.386 to 3.000.There were significant differences in the contents of mineral elements in different parents,and the experimental materials were the ideal parents for hybrid breeding.The GCA showed that CX-b,CX-c,CX-f,15-1,15-4 and 15-5 had a better effect on increasing the contents ofCa,Mg,Fe and Zn in hybrid progenies.And 15-5 had a good effect on reducing the contents of Na and Mn in hybrid progenies.2.Heterosis analysis on agronomic traits,quality traits and mineral element contents showed: more than 80% of the cross combinations had positive mid-parent heterosis in plant width,leaf length and weight of main stalk.The heterosis of agronomic traits in Caixin was obvious,the same as mineral elements,more than 60% of the cross combinations showed positive mid-parent heterosis in contents of Ca,Mg and Mn.However,heterosis of quality traits were insignificant,while the positive mid-parent heterosis of cross combinations were less than 30%.Therefore,the hybridization had good effects on improving agronomic traits,cellulose content and mineral elements content in Caixin.3.The Grey Comprehensive Evaluation Approach combained with heterosis analysis indicated that 4 hybridized combinations were found to be with excellent comprehensive characters: the soluble protein content in CX-c×15-4 and CX-e×15-3were 3.642% and 3.767%,respectively.The content of Ca in CX-e × 15-3 was up to17.288mg/g.CX-f×15-6 was rich in vitamin C which was up to 103.668mg/100 g,also highly yield.And CX-d×15-3 was an early-maturing hybrids with good edible quality.4.The results of correlation analysis among agronomic traits,quality traits and mineral element contents showed a significant correlation between mineral elements of Fe,Mg,Zn and agronomic traits of yield and plant size,which indicated that mineral element fertilizers may be helpful to improve vegetable yield and mineral element contents but not the quality traits.In addition,better materials with high contents of mineral elements could be obtained by observing the agronomic traits.And high-zinc plants may mean high calcium,high magnesium,high iron,high manganese and low sodium.5.Significant differences were found in the mineral element contents among the root,stem and leaf.But the correlation coefficients were different.This study showed that leaves were more nutritious because they contained higher levels of Ca,Mg,Fe and soluble proteins,and the cellulose was lower(only 86.510% of stem)when compared to stems.According to the relationship,the effect of foliar fertilizer may be better than general fertilizer in increasing Zn content.6.Studies on the content changes of mineral elements in Caixin showed: planting would decrease the content of mineral elements in vegetable plants in some period,even may affect the content of mineral elements in harvest period.The change of mineral element contents among different maturity materials had similar tendency.However,the late-maturing material had more Na and Mg content which were 1.241 times than the early material,The result indicated that the longer growth period is beneficial to the accumulation of some mineral elements in the plant.In addition,according to the change of mineral contents before and after the harvest period,the content of Ca and Zn was higher if Caixin was picked ahead of harvest time,and the content of Mg and Fe is higher if Caixin is picked according to the normal schedule. |
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