不同砧穗组合对红肉蜜柚树体和果实品质的影响

为研究张家界地区不同砧木类型对红肉蜜柚树体和果实品质的影响，以2 种砧木和4 种中间砧类型的红肉蜜柚为试材，对植株生长势、果实内在和外在品质进行测定和比较。结果表明，不同砧穗组合红肉蜜柚植株生长势表现出较大差异，其中酸柚砧和菊花芯柚中间砧组合株高最高，温州蜜柑中间砧组合株高最低；酸柚砧亲和性较好，枳砧亲和性较差，存在明显“大脚”现象；椪柑中间砧的接穗粗度明显大于中间砧，其他组合均略小。不同砧穗组合对红肉蜜柚果实品质有明显影响。外在品质方面，酸柚砧和椪柑、菊花芯柚中间砧组合果实体积明显大，单果重也明显高；果实中心柱大小与果实大小有较高相关性；砧穗组合类型对果形指数影响不大。内在品质方面，椪柑中间砧组合果实可溶性固形物含量明显 低，而酸柚砧和菊花芯柚中间砧组合果实可滴定酸含量明显高于其他组合。以酸柚为砧木，树势旺盛、果实体积大、单果重更高，虽然可滴定酸稍高，但是可溶性固形物含量也不低，同时不存在与接穗品种不亲和的现象，所以酸柚的综合表现比较均衡，是目前比较适合用作红肉蜜柚砧木的类型。本研究为张家界地区发展红肉蜜柚产业，提高产量、改善品质提供了参考。

Effect of Different Scion/Rootstock Combinations on Tree Growth and Fruit Quality of Red-flesh Sweet Pomelo

Objective]The influence of rootstock on the horticulture and pathology characteristics, especially on scion varieties, growth, yield, fruit size, fruit quality and resistance, which directly decides the economic benefit of orchard. The selection of suitable scion/rootstock combination is an important prerequisite for good quality and high yield of citrus. In the country of origin of sweet pomelo, Fujian, sour pomelo (Citrus Grandis Osbeck) is used extensively as rootstock in nursery stock production. Trifoliata orange (Poncirus trifoliata L.) is one of the most common rootstock in citrus seedling industry of our country, which showed no graft compatibility in the late age of seedling grafting. The traditional citrus industry is satsuma orange, ponkan and a local variety ‘Juhuaxinyou’ in Zhangjiajie area, Hunan province. Red-flesh sweet pomelo industry developed in great area by seedling field planting or budling top graft which was introduced from Fujian province. There for, trifoliate orange and sour pomelo as stock or trifoliate orange as the base stock and navel orange, pokan, satsuma orange, ‘Juhuaxinyou’ as the inter stock becoming the features new of the scion/rootstock combination. Graft incompatibility such as premature aging of tree vigor, abscission layer in graft union, big and small foot, etiolation of branches and leaves appear on different scion/rootstock combination, which has caused a severe economical loss. The screening out of scion/rootstock combination with good wide compatibility and growth vigor has become an extremely urgent duty. In this study, to explore the most suitable rootstock type of red-flesh sweet pomelo, the canopy, plant height, scion/rootstock coarseness of tree and the weight of single fruit, thickness of rind, newel size, vertical and transverse diameter, the soluble solid (TSS) and titratable acid (TA) content of the fruit were measured for evaluating the effect of different rootstock types on tree growth and fruit quality of red-flesh sweet pomelo. Method]6-year-old red-flesh sweet pomelo trees with trifoliate orange and sour pomelo as stock and 4-year-old trees with trifoliate orange as the base stock and navel orange, pokan, satsuma orange, ‘Juhuaxinyou’ as the inter stock were used as material in this study. The row spacing is 4 m and plant spacing is 3 m. 10 test trees were measured for growth vigor and 10 test fruits were measured for fruit shape in each combination. The tree canopy and plant height were measured with a tape measure. The weight of single fruit was weighed by electronic scales. The thickness of rind, newel size, vertical and horizontal diameter was measured with vernier caliper. TSS and TA content of the fruit were measured by the method of national standard GB 8210-2011. Inner quality estimated by mixed juicing sample which was composed of 10 fruit and 20 g sarcocarp from each one. Data in the paper are all average value. Data analyses were performed by using SAS statistical package; statistically significant differences were identified using analysis of variance (ANOVA); multiple comparisons were compared using the method of least significant difference (LSD). Result]Rootstocks and inter-stocks were found to have significant effects on plant growth, fruit internal and external quality. The red-flesh sweet pomelo grafted on sour pomelo and top grafted on ‘Juhuaxinyou’ showed higher plant height—at 3.05 and 3.70 m respectively, and which top grafted on Mandarin orange showed the lowest—at 2.23 m. The trees had stronger affinity with sour pomelo than trifoliate orange on which showed ‘Bigfoot’. The scion girth on ponkan showed obviously bigger than inter-stock which scion/stock girth ratio is 1.28, other combinations are all small than 1. To external quality, red-flesh sweet pomelo grafted on sour pomelo and top grafted on ponkan, ‘Juhuaxinyou’ had longer vertical and transverse diameter than 160 mm and high single fruit weight than 1400 g. There was significant relationship between fruit size and central axis. The types of scion/rootstock combination had little effect on fruit shape index. To internal quality, the fruits budded on ponkan inter-stocks had lower soluble solid contents—at 9.57 %, while the fruits budded on sour pomelo rootstocks and ‘Juhuaxinyou’ inter-stocks had apparently higher titratable acid contents than other combination—at 1.47 % and 1.48 % respectively. Conclusion]Using sour pomelo as rootstock, it always shows strong and vigorous growth, big and heavy fruit, slightly high TA, not low TSS, at the same time there also graft compatible with scion. So, the comprehensive behavior of sour pomelo is relatively balanced which is the suitable rootstock style that can be used for red-flesh sweet pomelo. This research provides a reference for the industry of red-flesh sweet pomelo and improvement of yield and quality.