Quantitative trait loci for fruit size and flowering time-related traits under domestication and diversifying selection in cucumber (Cucumis sativus)

In cucumber, the genetic basis of traits under domestication and/or diversifying selection is not well understood. Here, we reported QTL mapping for flowering time and fruit size-related traits with segregating populations derived from a cultivated × wild cross. Phenotypic data of flowering time (FT), fruit size (FS), fruit number (FN) and fruit weight per plant (FW) were collected in multiple environments. QTL analysis identified 19 QTL for these traits. We found that the major-effect QTL FT1.1 played an important role in regulating flowering time in cultivated cucumber, whereas the minor-effect QTL FT6.3 contributed to photoperiod sensitive flowering time during domestication. Two novel consensus FS QTL, FS1.4 and FS2.3, seem to be the targets of selection during breeding for the US processing cucumber. All other FS QTL were co-localized with previously detected QTL using populations derived from cultivated cucumbers, suggesting that they were under selection during both initial domestication and subsequent improvement. Results from this study also suggested that the wild cucumber is a useful resource for capturing positive transgressive segregation and novel alleles that could be explored in cucumber breeding.     

白马鸡人工驯养初步研究

通过人工饲养的方式探索出白马鸡驯养的经验,即:在野生白马鸡适宜生境下建立饲养场,从育雏阶段开始进行人工投食饲养和本地土鸡带领相结合的驯养方式。目前已经完成从子一代到子二代的完整驯养、饲养流程,取得了云南省林业厅的驯养繁殖许可证。对育雏、亚成体、成体阶段的喂食量、存活情况等作了分析,认为接近原始生境的环境及本地带雏母鸡是成功的重要条件。     

水稻落粒性的研究进展

落粒性是野生稻适应自然环境和保持群体繁衍的重要性状,落粒性的丧失是水稻驯化过程中的一个关键事件。落粒程度既直接影响水稻的产量,也影响其对现代化机械收割方式的适应性。本文综述了近年来水稻落粒性的研究进展,包括水稻落粒的生理基础、落粒性基因的定位与克隆,以及调控落粒性的分子机理。     

基于高通量GBS-SNP标记的栽培燕麦六倍体起源研究

栽培六倍体燕麦是世界重要粮食作物,理清其起源对燕麦种质资源的高效利用和保护具有重要意义。本研究利用GBS (genotyping by sequencing)对27份来自中国的大粒裸燕麦材料测序,结合先前发表的包括6个六倍体燕麦种在内的66份燕麦材料的GBS数据进行SNP挖掘。UNEAK管道挖掘共计得到MAF大于0.5, call rate大于0.95的SNP标记8902个。进一步剔除缺失值大于0.15的4个燕麦材料后,对其余89份材料进行PCA分析、STRUCTURE分析以及UPGMA聚类分析。结果表明,在野生种中,除A. sterilis外,大多数来自同一物种的材料聚为一类,不同物种间能够较好地分开,表明这些物种之间存在较强的遗传分化。聚类分析将供试材料分为分别代表野生种和栽培种的2支,表明野生种和栽培种之间存在明显的遗传差异;在栽培种中, A. sativa与A. byzantina具有较高的遗传多样性,分散在不同的类群中,二者未出现明显的遗传分化,具有较高的遗传同质性, A. sativa ssp. nuda与A. sativa亲缘关系较近,但存在一定的遗传分化,因此形成独立的类群。值得注意的是,来自野生种A. sterilis的材料被分在2个类群中,其中来自西南亚地区(伊朗-伊拉克-土耳其地区)的居群与A. sativa和A. byzantina聚在一起,揭示此地区的A. sterilis居群可能是A. sativa和A. byzantina的祖先种。野生种A. hybrida显示出与A. fatua较高的遗传同质性,因此将其作为A. fatua的亚种较为合理。本研究为栽培六倍体燕麦起源提供了理论依据。     

Seed Shattering of Cañahua (Chenopodium pallidicaule Aellen)

Cañahua (Chenopodium pallidicaule Aellen) is a semi‐domesticated relative of quinoa (Chenopodium quinoa Willd.) with high nutritious quality. It is tolerant to frost, drought, saline soils and pests. One seed yield limitation is seed loss during the maturity stages. Two greenhouse experiments in Denmark and field experiments in Bolivia were carried out to determine seed shattering in landraces and cultivars with different growth habits. 15–21 % of the seed shattering in the fields took place whilst the plants still were flowering and 25–35 % during physiological maturity. Seed shattering varied between locations on the Bolivian Altiplano. Cañahua types with the semi‐prostrate growth (‘lasta’) had the highest seed shattering rate in the greenhouse experiments. The Umacutama landrace had lower seed shattering (1 %) than the cultivar Kullaca (7.2 %) both of the ‘lasta’ type. Under field conditions, the cultivar Illimani with the erect growth (‘saihua’) had the highest seed shattering rate (6.4–33.7 %) at both locations and at four different sowing dates. The Umacutama had the lowest rate (0.5–1.5 %). There were no significant differences between plants of the ‘lasta’ and the ‘saihua’ types. The landrace had significantly less seed loss than the cultivars. However, in the greenhouse, the landrace yield was approximately 25 % lower than the yields of the cultivars. In general, cañahua cultivars had higher yield compared to landraces, but also a higher seed shattering rate. Landraces may be used in breeding programmes to develop high‐yielding cultivars with reduced seed shattering.     

Comparing genetic diversity in agroforestry systems with natural forest: a case study of the important timber tree Vitex fischeri in central Kenya

It is possible that current tree domestication practices undertaken by farmers reduce the genetic base of tree resources on farms, raising concerns regarding the productivity, sustainability and conservation value of agroforestry ecosystems. Here, we assessed possible changes in genetic variation during domestication in the important and heavily utilised timber species, Vitex fischeri Gürke (syn. Vitex keniensis), by comparing geographically proximate forest and farm material in central Kenya. Employing RAPD analysis, a total of 104 polymorphic markers revealed by five arbitrary primers were scored in a total of 65 individuals, 32 from forest and 33 from farmland. Despite concerns of possible genetic erosion, forest and farm stands did not differ significantly in levels of genetic variation, with H values of 0.278 and 0.269, respectively. However, Mantel tests did reveal greater geographically related associative genetic structure among individuals in farm rather than forest material, with r _M values of 0.217 and 0.114, respectively. A more detailed analysis of structure suggested this could be due to local variation in origin of some on-farm trees. Implications of data for the genetic management of V. fischeri stands during farmer-led tree domestication activities are discussed. At present, there appears little reason to reject on-farm V. fischeri as a source of germplasm for future on-farm planting or for conservation purposes, although this situation may change and will require monitoring.     

野生盾叶秋海棠引种驯化及应用研究

1997～2001年，采集西畴、麻栗坡野生盾叶秋海棠，引种至昆明市植物园温室区，通过物候观察，繁殖，生态适应性试验，证明引种的盾叶秋海棠生长健壮，正常开花结实，繁殖后代，可用于室内观赏或作为林下地被。     

树木引种驯化的生态限制条件探索

在昆明树木园的树木引种驯化工作中 ,探讨了引种树木的生存、生长、发育受引种地常年性和偶发性生态条件影响的程度以及引种树种对新环境条件的适应能力。一定的生态环境 ,对一些树种是适生条件 ,对另一些树种则是生存、生长发育的限制条件。这决定于树木的遗传变异性。由于各树种的遗传变异性不同 ,因而在受引种地生态条件影响的程度上存在种间差异 ,相同树种个体间也存在一定的遗传差异 ,种内在受引种地生态条件影响的程度上也存在着个体差异。引种树木对引种地的新环境的适应能力可分为相似生态适应能力、潜在适应能力和可塑性适应能力。这种适应能力也存在种间和种内个体差异 ;适应能力的大小是该引种树木在新环境中能否存活以致正常生长发育的关键。研究引种地常年性和偶发性生态条件对引种树木的影响和引种树木的适应能力 ,可以开扩树木引种驯化视野 ,使树木的引种驯化工作取得显著成效     

观光木人工林驯化栽培试验和系统生产力研究

本文对观光木驯化栽培环节中的采种、育苗、造林、管抚等摸索了一定的经验,并用分层切割法测定10年生样本地上部分各器官的生物量,用壕沟法测定地下部分根系的生物量。结果表明:10年生林分生物量为55.03t/hm~2,其中乔木层为53.035t/hm~2(占96.37%),乔木层中树干、枝、叶和根系分别为37.91t/hm~2、6.17t/hm~2、2.21t/hm~2和6.75t/hm~2。18年生解析木数据表明:胸径、树高和材积速生期分别出现在4—12年、5—7年和第14年。