Genetic improvement of farmed tilapias: Biochemical characterization of strain differences in Nile tilapia

Four African wild strains (Egypt, Ghana, Senegal and Kenya) and four established Asian farmed strains of Nile tilapia, Oreochromis niloticus (popularly known in the Philippines as Taiwan, Thailand, Singapore and Israel) were analysed electrophoretically at 30 protein loci to estimate genetic differences among the strains. All strains shared alleles at 14 monomorphic and 16 variable loci. Among the African strains, characteristic allele frequency differences were observed at AAT-1 ^* 46 for Ghana and Senegal, ADH ^* 83 for Kenya, ADH ^* 120 for Senegal, G3PDH-2 ^* 300 for Egypt, IDDH ^* 67 for Senegal, sMDH-1 ^* 120 for Kenya and SOD ^* 150 for Senegal. Genetic distance values among the strains revealed a clustering of the farmed strains with Egypt and Ghana O. niloticus, a slight separation of the Senegal strain and a larger separation of the Kenya strain. This profile may reflect the origins of the few founder populations of this species previously introduced to Asia. It also confirms the wider genetic divergence of the Kenya strain (O. niloticus vulcani) from the others studied here, which are all O. n. niloticus. Observed heterozygosities of the strains ranged from 0.026 to 0.071, with the African wild strains the lower values (mean Ho = 0.036) and the farmed strains the higher ones (mean Ho = 0.056). The implications of these results to the ongoing tilapia genetic improvement programme in the Philippines are discussed.     

日本沼虾4种群肌肉营养品质的比较

4个种群日本沼虾(Macrobrachium nipponensis)于2001年8月分别取自太湖、洪泽湖、广西南宁3地天然水域及浙江德清养殖种群。肌肉营养成分测定结果表明,养殖种群的粗蛋白含量为(15.83±0.32)％(质量分数),显著低于3个野生种群(P<0.05),而粗脂肪质量分数为(1.37±0.02)％显著高于野生种群(P<0.05)。3个野生种群中洪泽湖种群鲜味氨基酸含量最高;但太湖种群粗蛋白含量(17.71±0.38)％最高,必需氨基酸组成最为均衡,且单不饱和脂肪酸总量和多不饱和脂肪酸总量均为最高,分别达25.904％和35.953％。比较得出太湖种群日本沼虾肌肉的营养品质最高,养殖种群最低。     

福建省野生豆科植物资源及植物生态地理区系分析

对福建省野生豆科植物资源调查表明,福建省野生豆科植物有233种80属(包括变种、亚种),其中单种属、2～4种属居多并占绝对优势,分别占总属数的47.50%和30.50%。对福建省野生豆科植物资源生态地理区系分析表明,植物区系成分在属、种的水平上有13个类型,4个亚型,植物区系特征在属的水平上以热带成分为主,其中热带分布属有53属,占总属数的68.83%,可见本区系属的热带成分占明显优势,具有明显的热带性质。在种的水平上以泛热带分布类型占较大比例,其他多种分布类型并存,表现为丰富的物种多样性特征。     

橡胶树1981’IRRDB野生种质预割诱导次生乳管分化的比较分析

巴西橡胶树树干树皮中的次生乳管是天然橡胶合成和贮存的主要组织,次生乳管列的多少与胶乳产量密切正相关。割胶是天然橡胶生产中的核心环节,是当前获得天然橡胶的唯一途径,而割胶伤害能诱导次生乳管分化。采用碘-溴染色方法和石蜡切片技术,观察预割前后1981’IRRDB野生种质成龄树的树皮结构,对不同种质预割前后黄皮层和水囊皮区域的乳管列进行统计,并分析新分化的次生乳管列。研究结果表明,选取的85份8年生野生种质在自然条件下的乳管分化能力普遍较弱,黄皮层和水囊皮中成列的次生乳管数量均较少,2个部位合计乳管列数普遍低于8列。预割后不同种质水囊皮中次生乳管列数普遍增多,但黄皮层尚无明显变化。根据伤害诱导分化新的次生乳管列数的多少,将预割诱导乳管分化的能力由低到高分为1、2、3级,分别对应于新分化乳管列数为少于2列、2~3列(含2列)、3~4列（含3列）。在85份种质中,对应1级57份、2级23份、3级5份的种质,所占比例分别为67.06%、27.06%、5.88%,可见,诱导分化次生乳管能力强的种质占比较低,大部分种质为1、2级乳管分化,3级分化能力的种质极少。被诱导新分化次生乳管的能力与种质在自然条件下的分化能力有关,尤其是高乳管分化能力的种质通常在自然条件下也有较强的分化乳管的能力。通过预割判断乳管分化能力不仅为野生种质鉴定和评价奠定基础,也为橡胶树高产育种以及早熟、晚熟品种的早期预测提供有效指标。     

东乡野生稻种质资源保护现状、存在问题及对策

通过对江西省东乡野生稻种质资源的野外调查,结合东乡野生稻原生境保护区实地监测结果,分析了东乡野生稻种质资源保护现状及其存在的主要问题,提出了进一步保护和利用的对策,为更好保护东乡野生稻种质资源和研究利用提供借鉴。     

Dissecting Genetic Basis of Deep Rooting in Dongxiang Wild Rice

Deep rooting is an important trait in rice drought resistance. Genetic resources of deep-rooting varieties are valuable in breeding of water-saving and drought-resistant rice. In the present study, 234 BC₂F₇ backcross introgression lines were derived from a cross of Dongye 80 (an accession of Dongxiang wild rice as the donor parent) and R974 (an indica restorer line as the recurrent parent). A genetic linkage map containing 1 977 bin markers was constructed by ddRADSeq for QTL analysis. Thirty-one QTLs for four root traits (the number of deep roots, the number of shallow roots, the total number of deep roots and the ratio of deep roots) were assessed on six rice chromosomes in two environments (2020 Shanghai and 2021 Hainan). Two of the QTLs, qDR5.1 and qTR5.2, were located on chromosome 5 in a 70-kb interval. They were detected in both environments. qDR5.1 explained 13.35% of the phenotypic variance in 2020 Shanghai and 12.01% of the phenotypic variance in 2021 Hainan. qTR5.2 accounted for 10.88% and 10.93% of the phenotypic variance, respectively. One QTL (qRDR2.2) for the ratio of deep roots was detected on chromosome 2 in a 210-kb interval and accounted for 6.72% of the phenotypic variance in 2020. The positive effects of these three QTLs were all from Dongxiang wild rice. Furthermore, nine and four putative candidate genes were identified in qRDR2.2 and qDR5.1/qTR5.2, respectively. These findings added to our knowledge of the genetic control of root traits in rice. In addition, this study will facilitate the future isolation of candidate genes of the deep-rooting trait and the utilization of Dongxiang wild rice in the improvement of rice drought resistance.     

四方井水利枢纽工程古树名木和重点保护野生植物分布现状及保护对策

通过野外调查查清了宜春市四方井水利枢纽工程项目区内古树名木及重点保护野生植物的种类、数量、生境类型、保护等级、生长势、保护管理现状及根系生长情况,结合工程项目的要求,提出了对古树名木及重点保护野生植物的保护对策,将工程建设对古树名木及重点保护野生植物资源的负面影响控制到最小,并为项目建设单位、有关政府机构制定和实施生态环境管理、监测计划提供科学依据.     

野生红小豆品系 JH01的筛选与应用效益

为筛选出具有一定经济价值且适合林地栽培的红小豆品系,从野生红小豆群落中,根据种子颜色、抗病虫害特性、株高和产量4个方面筛选满足要求的红小豆品系。通过选择获得红小豆品系 JH01,其种子为红色、株高超过4 m、病虫危害轻,产量潜力高（1．58kg/株）,符合品系筛选目标。该红小豆品系能满足林地栽培要求,具有较高的经济价值。     

南岳衡山野生药用植物资源组成及药用特点

采用查阅资料和线路调查与样地调查相结合的方法,研究了南岳衡山野生药用植物资源组成和药用特点。结果表明:南岳衡山药用植物有167科467属817种,其中蕨类植物32科49属100种,裸子植物4科4属4种,被子植物131科414属713种。含10种药用植物以上的科有21科,其中菊科56种,蔷薇科33种,蝶形花科30种。817种药用植物中,木本植物254种,占31.09%,草本植物563种,占68.91%。各类药用功效植物占药用植物总数的比例变化范围在0.49%~33.78%之间,相差较大,属于I级(10.00%)有14类,II级(10.01%~20.00%)有3类,Ⅲ级(20.01%)有5类。药用植物中,同类器官入药的植物种数占药用植物总种数的百分比变化范围在0.98%~32.80%之间,其中一级(10.00%)所含植物的器官有木材类,节类,藤及藤茎类,树(枝)皮类和花类等5类,占器官总类别的50.00%;二级(10.01%~20.00%)所含植物的器官有茎及地下茎,果及种子类,枝叶等3类,占30.00%;三级(20.01%)有全株类和根及根皮类,占20.00%。药用植物中,直接用于临床的药材泡制材料的维管束植物有220种。