Biological Characteristics And Molecular Marker Analysis Of Luhong Citrus

Ponkan (Citrus reticulate Blanco) is a native variety to China and it is widely distributed in China. It is popular with consumers by its good quality and long storage length. The color of ponkan fruit in markets usually is orange yellow or orange, but there has been no report about the mechanism of the fruit peel color of ponkan with orange-red or red.'Luhong'was found in an ordinary ponkan orchard of Luxi County in 2001. Its fruit peel color is orange-red. With many years' observation, all the genetic traits of'Luhong'appear stable. In this research, the phenology and plant morphology of'Luhong'and'Luxi'ponkan have been observed. And the fruit qualities were also studied to analyze their differences. The relationships of'Luhong' and'Luxi'ponkan, as well as some other common citrus varieties were analyzed by using SRAP molecular markers. With clustering and principle coordinates analysis by NTSYS-pc software, the genetic relationship of 'Luhong' has been explored. The results are as follows:1 There are difference between'Luhong'and'Luxi'ponkan in fruit peel color, fruit size, pericarp thickness and seed shape. The fruit peel color of'Luhong'is orange-red, but orange in'Luxi'ponkan. The phenologies, growth vigor, shoot growth, leaf shape and leaf size is the same.2 Not only the appearance but also the quality presented difference between'Luhong' and'Luxi'ponkan. The average soluble solids in'Luhong, is 14.06%, campanied with 11.94% total sugar,1.18% total acid, and 45.82mg/100ml Vc content; By contrast, there are 12.06%soluble solids,11.16% total sugar,1.00%total acid and 36.34mg/100ml Vc content in 'Luxi'. The peel carotenoid content of 'Lu hong' is 430.37μg/g-FW, which is 1.65 times than that in'Luxi'ponkan. It can be deduced that the changed carotenoids content in'Luhong'resulte in the orange-red color in its fruit peel.3 The data of SRAP and SCoT molecular marker was analyzed by NTSYS-pc software. The results showed that 'Luhong' belongs to orange class of citrus, posesse the highest similarity coefficient to ponkan and have the closest relationship with ponkan, which can be deduced that the'Luhong'is a variation of the'Luxi'ponkan.