Crossbreeding of the elite clones is an important strategy to breed the new germplasms of Camellia oleifera capable of higher oil yield and quality. While the genetic control model and heterosis of oil-related traits in C. oleifera remains challenging. To improve the breeding efficiency, several genetic parameters were evaluated in this study based on a 5 x 5 complete diallel design of C. oleifera. A total of seven oil-related traits were measured for three years in the F1 progenies, including oil content of dry kernel (OC) and the contents of six kinds of fatty acid in the oil. For these seven traits, we calculated their parental general combining ability (GCA), special combining ability (SCA) and heritability. And the changed heterosis in F1 progenies during the growth period was analyzed. The results showed that the GCA and SCA of parents for most of the traits had significant differences among the crosses. And the ratio of GCA to SCA ranged from 1.67 to 2, meaning that the SCA was more important than GCA in C. oleifera breeding. The broad-sense heritability for the seven traits were from 11.74% to 53.38% and these traits were significantly affected by environmental factors. And the variation of heterosis were different at different traits. According to the assessed combining ability, heritability and heterosis, three parental combinations were suggested to use in C. oleifera crossbreeding, which harbored greater potential to produce the progeny with optimal oil-related traits. The cross CL4 xCL40 was most apt to obtain superior progeny in terms of OC and C16:0. Whereas the cross CL4 xCL53 would be also the better choice for culturing progeny with a high OC content. The cross CL10 xCL53 and CL95 xCL53 would be likely to beget superior progeny for the C18:1 and C18:2 content, respectively.

Camellia oleifera is a major tree species for producing edible oil. Its seed oil is well known for the high level of oleic acids; however, little is known regarding the molecular mechanism of lipid biosynthesis in C. oleifera. Here, we measured the oil contents and fatty acid (FA) compositions at four developmental stages and investigated the global gene expression profiles through transcriptomics sequencing. We identified differentially-expressed genes (DEGs) among the developmental stages and found that the distribution of numbers of DEGs was associated with the accumulation pattern of seed oil. Gene Ontology (GO) enrichment analysis revealed some critical biological processes related to oil accumulation, including lipid metabolism and phosphatidylcholine metabolism. Furthermore, we investigated the expression patterns of lipid biosynthesis genes. We showed that most of the genes were identified with single or multiple copies, and some had correlated profiles along oil accumulation. We proposed that the higher levels of stearoyl-ACP desaturases (SADs) coupled with lower activities of fatty acid desaturase 2 (FAD2) might be responsive to the boost of oleic acid at the late stage of C. oleifera seeds’ development. This work presents a comprehensive transcriptomics study of C. oleifera seeds and uncovers valuable DEGs that are associated with the seed oil accumulation.

In this paper,the orthogonal design was used to optimize ISSR amplification system of Larix in five factors(Mg~(2+),dNTP,primer,Taq polymerase,DNA templet) at four levels respectively.The data were analyzed by soft ware MINITAB.A suitable ISSR reaction system was established,namely 20 μl reaction system containing 50-200 ng DNA templet,0.5 μmol/L primer,1×PCR buffer,0.15 mmol/L-0.2 mmol/L dNTP,1U Taq DNA polymerase,2.0 mmol/L-2.5 mmol/L Mg~(2+).The optimal annealing temperature for ISSR-PCR reaction was proposed by gradient PCR.

通过对樟子松叶、枝、芽、果等部位进行组织切片和真菌分离培养,鉴定出真茵24种,其中子囊茵3种、担子茵1种、半知茵20种.这些真菌种群在樟子松树体上可分为芽栖真菌、叶栖真茵、枝栖和果栖真菌4大类,其种类组成和数量与樟子松树龄、叶龄、枝龄、树冠层次等有密切关系.芽栖真菌种类和数量随树龄的增加而增多,叶栖真菌(特别是兼性寄生真茵)的种类和数量随叶龄的增加而增多,枝栖真菌种类和数量随枝龄的增加而增多.樟子松树栖真菌种群组成也随环境条件而发生变化,在发病的樟子松林分内樟子松枯梢病菌数量激增占主导地位,环境条件的恶化是促成变动的主要原因.在健康的樟子松林分内也广泛地分离到樟子松枯梢病菌,表明该病害是潜伏性的侵染病害.

试验筛选出10种对樟子松枯梢病病原茵Diplodia pinea有拮抗作用的真菌,最终确定具有拮抗作用的真菌6种.拮抗效果由强到弱依次为绿木霉(Trichoderma viride)、单格孢(Ulocladium chartarum)、枣褐霉(Spadicoides oboratum)、镰刀茵(Fusarium sp.)、球毛壳孢(Chaetomium globosum)、附球茵(Epicoccum sp.).其中绿木霉效果最好,为首选茵种.拮抗茵的筛选以相对抑茵效果为准,同时应考虑被抑制率和菌种本身具有的致病性.

应用森林病理学的研究方法,通过对病区和非病区不同时期健康株针叶、芽、梢、枝、果等不同部位的组织进行分离培养、接种和套袋隔离试验,测定樟子松枯梢病在病区和非病区健康株上的潜伏侵染带菌率,并对照病区和非病区不同部位、不同时期健康组织的分离培养结果进行分析研究,以得出樟子松枯梢病的潜伏侵染规律,为此病的防治提供一定的理论依据.