| 【Objective】In order to obtain suitable rootstocks for Orah and suitable planting areas in Guangdong, the comparison of Orah grafted on different rootstocks and introduction performance in Guangdong were studied. The results can provide a basis for highly efficient production of Orah. 【Method】Red tangerine（Citrus reticulata Blanco cv. Red tangerine）, fragrant citrus（Citrus junos Sieb. Ex Tanaka）and poncirus trifoliata〔Poncirus trifoliate（L.）Raf.〕were taken as grafting rootstocks for Orah. The affinity, tree growth, early fruiting and fruit quality of different rootstock-scion
combinations of Orah were studied. And the introduction performance of Orah in eastern, western and northern Guangdong was observed to systematically understand the adaptability of Orah in Guangdong.【Result】The Orah on the three rootstocks showed the advantages of strong scion affinity and rapid crown formation. Among them, the fragrant citrus rootstock plants grew vigorously, the red tangerine rootstock plants grew moderately, while the trifoliate rootstock plants grew moderately and dwarfed obviously. The Orah on red tangerine rootstock and trifoliate orange rootstock had higher yield at early fruiting stage, reaching 8.8 kg/plant and 8.5 kg/plant, respectively, with early fruiting and better high yield stability, while the initial yield of fragrant citrus rootstock was low, only 6.5 kg/plant. However, the effect of rootstock on yield was not obvious after 2 years. The single fruit weight of red tangerine rootstock was the highest, with an average of 150.07 g, followed by that of fragrant citrus rootstock, with an average of 141.83 g and the lowest was found in poncirus trifoliata rootstock, only 132.13 g. The single fruit weight between red tangerine rootstock and poncirus trifoliata rootstock reached a significant difference level. The contents of soluble solids, total sugar and total acid were the highest in trifoliate orange rootstock and the lowest in fragrant citrus rootstock. The differences of soluble solids, total sugar and total acid between trifoliate orange rootstock and fragrant citrus rootstock were significant in the first two years, however, the differences were not obvious after 3 years. The phenological period of Orah was affected by the planting area. In eastern and western Guangdong, the shoot period and flowering period were about 30 days earlier than those in northern Guangdong, and the fruit ripening period was about 20 days earlier than that in northern Guangdong, but the colorchanging period was about 10 days later. The cultivation of Orah in different regions of Guangdong had the characteristics of good early fruiting, high yield and excellent fruit quality, but the fruits and autumn shoots of Orah in northern Guangdong were sensitive to frost.【Conclusion】Red tangerine and fragrant citrus are excellent rootstocks and worthy of promotion, while poncirus trifoliata is prone to yellowing and premature senility after high yield, therefore, it is not recommended to be used as grafting rootstocks for Orah. Orah is not suitable for large-scale cultivation in northern Guangdong due to its vulnerability to freezing injury. |
