Comparative Analysis And Evaluation On The Expression Of Traits Of Oil Tea(Camellia Oleifera) Superior Clones

Oil-Tea belongs to Camellial. L. of Theaceae which is a unique and important edible woody oil plant in southern China and which has high economic value and high oil content. It is one of the four famous oil plants in the world.Comparative analysis and evaluation have been carried out on morphological characters, individual variability, growth traits and economic indexes, photosynthetic physiology of 6 Oil-Tea superior clones including"CHANGLIN"number3,number4,number27,number53,number56 and number166. Meanwhile, ISSR markers are used to detect their genetic relations for 11 Oil-Tea species including the above-mentioned 6 clones and"CHANGLIN"number18 , number21 ,number40,number59 and 1 control sample(seedling). The major conclusions are as follows:(1) Despite the great similarities of traits found in 6 clones, big differences are discovered in some morphological characteristics, which can be regarded as one of important factors to identify breeds. The differences include: number 27(16.57 cm2) belongs to large-leaved type, the opposite is number 166(9.25cm2) and number 3(9.00cm2); number 53 (length 3.7cm, diameter 4.13cm) belongs to large-fruit type, the opposite is number 166 (2.85cm,3.40cm); number 4 belongs to high bushy-branch type, the opposite is number 27 and number 3; number 56 belongs to high-thin type while number 53 is of low type; number 166 belongs to wide-crown type, the opposite is number 27.(2) Comprehensive evaluation of individual variability shows that the order of stability from stand to fall is number 3, number 4, number 53, number 166, number 56 and number 27. Comprehensive evaluation of growth speed shows that the order from stand to fall is number 4, number 3, number 166, number 56, number 53 and number 27. Four signs (yield, the percentage of fresh seed, content of tea oil in seeds, linoleic acid content) are chosen as comprehensive evaluation indexes to assess the economic traits of the six Oil Tea superior clones. The result shows that the order from stand to fall is number 3, number 56, number 53, number 4, number 166 and number 27. The comprehensive result shows that the best breed is number 3, followed by number 4, and the opposite is number 27 in the 6 Oil-Tea clones.(3) The main components in the seed of 6 clones are unsaturated fatty acids. The relative proportion of unsaturated fatty acids to their total amount of fat presents a descending order-- number 166(90.16%),number 4(89.81%),number 53(89.12%), number 27(88.69%),number 3 (88.47%) and number 56(83.61%). The relative proportion of linoleic acid to their total amount of fat also shows a descending order-- number 56 (14.09%), number 53 (10.81%), number 3(6.35%),number 27 (6.30%), number 166 (5.33%), number 4 (4.40%). (4) The curve types of daily change on net photosynthetic rate are roughly the same for the 6 Oil-Tea superior clones in the same growth stages, but a relatively big difference is found among a particular period in the photosynthetic rate which varies with the change of growth stages. The net photosynthetic rate is the lowest in July, the highest in September and followed in November in different growth stages. The variation tape of net photosynthetic rate in July and September are both"double peak curve". The peak occurs at 8:00a.m.and at 17:00p.m. respectively in July, and the numerical value at 8:00a.m.is bigger than that at 17:00p.m. The peak occurs at 10:00a.m.and at 17:00p.m.respectively in September, and the numerical value at 10:00a.m.is bigger than that at 17:00p.m. The variation tape of net photosynthetic rate in November is"singer peak curve"with the peak occurring at 12:00a.m.(5) ISSR marker method is used to detect the genetic diversity among 10 Oil-Tea superior clones and 1 control sample (seedling). The average genetic distance between genotypes of clones is 0.419,which is of closer distance compared with that between super clones and control sample (0.58).Clustering results are divided into three groups. GroupⅠis the control sample (seedling); Group II the number 4. GroupⅢcontains the other nine clones among which the genetic distance is closer between number 3 and number 18, number 27 and number 56, number 21 and number 40. Cluster analysis indicates some differences between clones which can be told from molecular level. At the same time agreements between expression of traits and genetic distance are discovered.(6) Changes are discovered in the order of the expression of all traits in individual variability, growth state and correlation degree because of the change of growth stages or ages. The major reasons are as follows: firstly, these clones are only 4～6 year old at the research stage, who need at least another 8～10 years to reach maturity. Secondly, there is a early yield when they are 3～4 years old. Therefore, it is difficult to balance nutrition and procreant growth. Thirdly, the simultaneousness of yielding and flowering leads to the contradiction of nutritious balance. Finally, different genetic traits exist among them.