A Early-ripening Characters Analysis Of Gannanzao Navel Orange

In Ganzhou County,Jiangxi Province,navel orange planting area has been ranked first in the world,with annual output up to million tons.But,the variety of navel orange is single,which is more than 90%varieties of Newhall navel orange.Therefore,the most important breeding imperative is to select navel orange variety of various maturity.Gannanzao navel orange is a spontaneous early-ripening mutant from Newhall navel orange.Compared with the ’Newhall’,we studied the early-ripening mutant’s chlorophyll content in fruit peel and main quality indicators in the fruit pulp during orange fruit ripening,analyzed the mutant peel volatile oil constituents and made the identification to the mutant in the DNA level.The main results are as follows:1.Through comparative analysis the orthogonal combination between extract methods and extraction reagents,we used the 95% ethanol grinding method is best the chlorophyll extraction of navel orange peel.2.There were significant differences in the peel chlorophyll content and the quality indexes of fruit between ’Gannanzao’ and the wild type during fruit development.In total,soluble solids,sucrose,glucose,fructose,vitamin C,malic acid and quinic acid contents in ’Gannanzao’ were apparently higher than in the wild type,but the peel chlorophyll,titratable acid and citric acid contents were apparently lower.’Gannanzao’ early-ripening fruit features were obvious,including the change of colour and lustre in advance,sugar accumulation up,TSS/TA jumps early during the same period.The appearance and inner quality compared with the wild type,’Gannanzao’ was ahead for more than 30 days.’Gannanzao’early-ripening character was stable in genes,for the quality indicators for the generation were consistent with the parent.In addition,’Gannanzao’ maturity showed early-ripening among five different areas.3.Volatile oil of Gannanzao navel orange peel and its control were extracted by using steam distillation,and then,the volatile oil components were identified and analyzed by GC-MS.The results showed that 54 and 61 kinds of components were identified respectively in ’Gannanzao’ and its wild type.There were 39 kinds of the same compounds in ’Gannanzao’ and its wild type which mainly including Limonene,(1S)-(-)-β-pinene,1R-α-pinene,Valencen and so on.But there were 37 kinds of particular compounds in them,of which the relative contents range from 0.025% to 0.806%.Two varieties of peel volatile oil components in the kinds and contents had greater differences,resulting in the aromas of ’Gannanzao’ and’Newhall’ has quite variance.4.The differences between ’Gannanzao’ and its wild type were analyzed at DNA level using SRAP and AFLP molecular markers.The results indicated that the difference at DNA level hadn’t been found between two types by SRAP,but one polymorphism fragment had been found by AFLP.The polymorphism fragment existed stably in the wild type and the early-ripening returned type,while didn’t exist in the most of ’Gannanzao’ samples.But it existed in the few of ’Gannanzao’ generation samples.This conclusion still needs to be verified further.However,it is certain that the polymorphism fragment did exit in the early-ripening returned type,which can be inferred that the polymorphism fragment may be associated with early-ripening features.