Correlation analysis and comprehensive evaluation were conducted on leaf anatomical structure and photosynthetic characteristics of five Camellia oleifera superior lines, and the relationship between leaf anatomical structure and photosynthetic capacity of five Camellia oleifera superior lines was explored, and the superior lines with the best photosynthetic characteristics were screened, so as to provide scientific basis for subsequent breeding, cultivation and popularization.

By artificial cross pollination between ‘Sanhua’ and ‘Xianglin 210’, five superior lines of Camellia oleifera were selected, namely ‘Huashi’ (‘Huashuo’ × ‘Huajin’), ‘Huazeng’ (‘Huajin’ × ‘Xianglin210’), ‘Huatuo’(‘Huajin’ × ‘Xianglin210’), ‘Huafeng’ (‘Huashuo’ × ‘Huaxin’) and ‘Huaping’ (‘Huajin’ × ‘Huaxin’). The chlorophyll content, stomatal characteristics, leaf anatomical structure and photosynthetic characteristics of the five superior lines were determined. Finally, correlation analysis and principal component analysis were used to analyze the five superior lines of Camellia oleifera.

It was found that ‘Huatuo’ had the highest leaf shape index, ‘Huashi’ had the largest leaf area, and the total chlorophyll content (10.06 mg·g^-1) was significantly higher than that of the other four superior lines of Camellia oleifera. ‘Huafeng’ had the best stomatal density (10.80/mm²), and the upper epidermis thickness of ‘Huazeng’ was the largest. However, the leaf thickness (523.23 μm), spongy tissue thickness (288.22 μm), palisade tissue thickness (171.40 μm) and transpiration rate of ‘Huaping’ were higher than those of the other four superior lines of Camellia oleifera. Correlation analysis showed that the net photosynthetic rate of leaves is negatively correlated with the thickness of palisade tissue and the ratio of palisade to leaf, and positively correlated with the thickness of leaves, the thickness of the upper and lower epidermis and TRPS. Principal component analysis showed that the cumulative contribution rate of four principal components extracted from 10 leaf traits reached 85.530%, among which the first, second, third and fourth principal components reflected 29.422%, 27.329%, 18.203% and 10.576% of the original data information, respectively, which could fully reflect the leaf anatomical structure and photosynthetic characteristics of Camellia oleifera superior lines. Based on the principal component analysis method, the comprehensive score of each superior line is calculated, and the order is ‘Huaping’, ‘Huatuo’, ‘Huafeng’, ‘Huazeng’ and ‘Huashi’ according to the comprehensive score from high to low.

This study revealed the relationship between leaf anatomical structure and photosynthetic characteristics of superior lines of Camellia oleifera, and screened the superior line ‘Huaping’ with the best photosynthetic characteristics, which provided an important reference for the breeding of improved varieties of Camellia oleifera. Future research should further combine multi-trait comprehensive evaluation and consider the influence of environmental conditions to improve the comprehensiveness and reliability of the research.

The study on the compatibility of interspecific hybridization between Castanea henryi and Castanea mollissima was carried out to overcome the obstacles of flowering period between C. henryi and C. mollissima, and to provide a theoretical basis for the creation of specific germplasm of Castanea.

Four varieties of C. henryi ‘Huali 1’ ‘Huali 2’ ‘Huali 4’ and ‘Dili 1’ are used as female parents and C. mollissima ‘Tanqiao’ as male parent to carry out interspecific cross pollination, and natural pollination of four C. henryi varieties as control to compare and analyze their compatibility and fruit quality.

The compatibility between four varieties of C. henryi and C. mollissima ‘Tanqiao’ was in the following order: ‘Deli 1’ > ‘Huali 4’ > ‘Huali 1’ > ‘Huali 2’, the highest seed setting rate was 42.41%, and the lowest seed setting rate was 28.93%. The growth trend of hybrid fruit and natural pollinated fruit was slow-fast-slow, and the growth trend of fruit was not affected by interspecific hybridization. The fruit ripening period of four interspecific hybrid combinations was affected by the male parent C. mollissima ‘Tanqiao’. The use of C. mollissima ‘Tanqiao’ pollination significantly increased the single grain quality, while also markedly raising their starch content, vitamin C content, and total flavonoid content, in which the single grain quality increased by 4.07%-27.92%, and the starch content increased by 5.21%-21.21%. The content of vitamin C increased by 6.37%-116.49%, and the content of total flavonoids increased by 9.80%-95.50%. The comprehensive evaluation of fruit quality by comprehensive direct evaluation method and average membership degree method showed that C. mollissima ‘Tanqiao’ improved the nut quality of ‘Huali 1’ most significantly.

The interspecific hybridization between C. henryi and C. mollissima has a certain compatibility, and different female parent varieties have different compatibility. The maturation period, nut size, nut quality and the number of nuts in a single bulb were greatly affected by the male parent. The interspecific hybridization between C. henryi and C. mollissima is a potential way to improve the quantity and fruit quality of individual spiny nuts.

To explore the effects of basic medium, hormone type and ratio on the bud and stem segment of Camellia oleifera belt, establish an efficient and rapid propagation system for C. oleifera in order to provide technical support for the commercial cultivation of C. oleifera in the future.

The stem segment with bud of a superior C. oleifera plant ‘Deyou No. 6’ was used as the test material to study the effects of basic medium, growth hormone and hormone ratio on primary bud induction culture, IBA, IAA, KT and other hormone ratio on proliferation culture, and quick dip IBA, salicylic acid treatment methods on rooting culture inside and outside the bottle. Determine appropriate disinfection methods and breeding and rooting media.

The axillary bud germination induced by IAA and IBA was significantly higher than NAA, and IAA was significantly better than IBA in promoting bud elongation. Both WPM and 1/2MS basic medium had good growth effect on bud induction, but WPM medium promoted the growth rate of bud. The orthogonal experiment of bud induction in stem segment of oil tea belt was designed with three hormones, 6-BA, IAA and GA₃, and the main factors were IAA > 6-BA > GA₃, A₁B₁C_1: WPM+1.0 mg/L 6-BA+1.0 mg/L IAA+2.0 mg/L GA₃, and the induction rate was 93.8%. With WPM+2.0 mg/L 6-BA+0.25 mg/L IBA+1.0 mg/L KT, the proliferation coefficient was 3.14, and the leaves were strong and green. For single bud treatment, the rooting effect was obvious when the base of the bud was rapidly soaked with 5.0 mg/mL IBA(10 s)+1.0 mg/L salicylic acid (20 s). The rooting rate reached 90.9% when the blank medium of 1/2MS (4g/L Agar) was added, and the rooting rate reached 87.5% when the medium of vermiculite+perlite was 1∶1.

The tissue culture and rapid propagation system of buds and stems of C. oleifera was established, especially the method of rapid dipping with high concentration of auxin was used to achieve a higher rooting rate by rooting inside and outside the bottle.