Selection of rootstock is very important for citrus production.  Besides its major role on resistance, the rootstock also can affect fruit production and quality.  Currently, the main concerns on selection of rootstock for citrus production are compatibility and resistance, due to less information on the impacts of rootstock to the performance of scion varieties.  This study aims to provide information on performances of navel orange varieties on different rootstocks.  Three late-ripening navel orange varieties (Citrus sinensis var. Powell, Chislett and Banfield) grafted on seven rootstocks (Swingle citrumelo (C. paradisi×P. trifoliata), Carrizo citrange (C. sinensis×P. trifoliata), X639 (C. reticulata×P. trifoliata), MXT (C. sinensis×P. trifoliata), Hongju (C. reticulata), Ziyang Xiangcheng (C. junos) and trifoliate orange (P. trifoliata)) were used as plant materials for comprehensive comparison of the performances on tree growth, fruit yield and quality in 21 scion–stock combinations.  Investigation was carried out in these combinations in field nine years after planting.  Vigorous growth of all the three late-ripening navel orange varieties was observed on Carrizo citrange with the largest canopy volume at 33.34 m³ and the highest yield at 29.43 kg per tree, but a low yield efficiency at 2.87 kg m^–3.  On the contrary, those on trifoliate orange had the smallest canopy volume at 10.79 m³ and the lowest fruit yield at 12.51 kg per tree, but the highest yield efficiency at 3.95 kg m^–3. Rootstocks did not show significant effects on fruit size, fruit shape index, peel thickness and the edible rate of the fruits, but fruit quality was significantly affected by the rootstocks.  Fruits from the trees grafted on trifoliate orange presented the best quality with significantly higher total soluble solids (TSS) content than those on Ziyang Xiangcheng and Hongju, and also the highest ratio of TSS/titratable acidity (TA).  The TA content was observed from the fruits on X639 at 0.59 g 100 mL^–1.  Vitamin C (Vc) content of fruits on Hongju was the highest at 49.25 mg 100 mL^–1.  Growth vigor of the trees was positively correlated with fruit yield at an extremely significant level.  The canopy volume was negatively correlated with yield efficiency, but positively correlated with compatibility index.  Results of this study indicated that the rootstock has great impacts on the growth vigor of the tree, yield efficiency and quality of the fruit.  In order to achieve good quality and yield efficiency for navel orange production, less growth vigor rootstock such as trifoliate orange is highly recommended. 

Aphelinus asychis is an important aphid endoparasitoid.  Under field and greenhouse conditions, high temperature is one of the factors limiting the application of A. asychis for biological pest control.  To explore the potential role of transient receptor potential (TRP) channels and heat shock proteins (HSPs) in this process, we identified 11 genes encoding TRP channels and nine genes encoding HSPs.  Three proteins (AasyTRPA5, AasyPyrexia, AasyPainless) that belong to transient receptor potential ankyrin (TRPA) subfamily and nine HSPs are involved in the response to high temperature.  We also investigated the survival of A. asychis and the response of the identified TRP channels and HSPs to high temperature.  The results showed that the maximum temperature that allowed A. asychis survival was approximately 41°C; females had higher survival rates than that of the males at 40 and 41°C.  Short-term heat-shock resulted in increased expression of Aasyshsp in males, and Aasyhsp40, Aasyhsp68, Aasyhsp70-4, Aasyhsp70-5 and Aasyhsp90 were upregulated and then downregulated, whereas Aasyhsp70-3 was upregulated at 41°C.  Moreover, Aasyhsp40 and Aasyhsp90 showed higher expression levels in females, while Aasyshsp and Aasyhsp70-3 presented opposite expression patterns.  At temperature above 35°C, expression of AasyPyrexia in females was significant higher than that in males, whereas AasyPainless and AasyTRPA5 presented higher expression in males at 40 and 41°C, respectively.  Altogether, these results indicate that protection against thermal stress in A. asychis is coordinated by TRP channels and HSPs.  These findings provide a basis for understanding the potential mechanism of A. asychis in response to high temperatures.