蓖麻杂交组合收获指数评价

为了提高蓖麻杂交育种效率,研究杂交组合收获指数与性状之间的关系,观察和测量了133个蓖麻杂交组合的13个农艺性状,即收获指数、单株产量、生物量、百粒重、有效穗数、一级分枝数、株高、茎粗、主茎节数、主穗长、主穗位高、叶绿素含量、净光合速率。采用相关分析和回归分析研究133个杂交组合的农艺性状间的关系。结果表明,不同蓖麻杂交组合的收获指数差异较大,变幅为0.126~0.644,平均值为0.398;133个杂交组合中收获指数在0.5以上的组合仅占16.54%。相关关系结果表明,收获指数与单株产量呈极显著正相关,与主穗长呈极显著负相关。回归分析表明,单株产量、株高、主穗长、有效穗数4个性状对收获指数的影响较大。因此在育种过程中,选择主穗花序较长、植株相对较高、一级分枝数较多的个体,可提高育成材料的单株产量。

蓖麻高光效种质的筛选

【目的】研究蓖麻不同种质的光合特性,为蓖麻高光效种质的筛选及利用提供参考。【方法】结合主成分分析与系统聚类分析等方法,对29份来自不同地区的蓖麻种质胞间CO_(2)浓度(Ci)、蒸腾速率(Tr)、气孔导度(Gs)、净光合速率(Pn)、叶片瞬时水分利用效率(WUE)和蒸腾效率(TE)6个光合参数综合评价,筛选出优异蓖麻种质。【结果】6个光合参数的变异系数范围为16%~35%。其中,Pn与Gs的变异系数最高、达35%;Ci的变异系数最低、为16%。相关性分析中,Pn与Ci呈极显著负相关,与Tr和WUE均呈极显著正相关。主成分分析结果表明,3个主成分可以解释6个光合相关参数的99.15%,3个主成分可称为光合因素、气孔因素和水分因素。光合参数聚类分析将29份蓖麻种质划分为4个类群。其中第Ⅱ类包括4个材料,占总材料数的13.79%,这些材料净光合速率最高,均超过整体材料净光合速率的平均值,且本类群中的Pn、Gs和Tr均处于较高水平。筛选出YSL-5、SD-21、A40-7、B11-1等4个材料作为适合育种需要的高光效蓖麻种质。【结论】Pn高、Gs大、WUE相对较高的一类种质可作为蓖麻高光效品种选育的中间材料加以利用。

Flesh Color Diversity of Sweet Potato: An Overview of the Composition, Functions, Biosynthesis, and Gene Regulation of the Major Pigments

Sweet potato is a multifunctional root crop and a source of food with many essential nutrients and bioactive compounds.Variations in the flesh color of the diverse sweet potato varieties are attributed to the different phytochemicals and natural pigments they produce.Among them,carotenoids and anthocyanins are the main pigments known for their antioxidant properties which provide a host of health benefits,hence,regarded as a major component of the human diet.In this review,we provide an overview of the major pigments in sweet potato with much emphasis on their biosynthesis,functions,and regulatory control.More-over,current findings on the molecular mechanisms underlying the biosynthesis and accumulation of carotenoids and anthocyanins in sweet potato are discussed.Insights into the composition,biosynthesis,and regulatory control of these major pigments will further advance the biofortification of sweet potato and provide a reference for breeding carotenoid-and anthocyanin-rich varieties.

Assessment of Castor Plant (Ricinus communis L.) Tolerance to Heavy Metal Stress-A Review

Increased urbanization and industrialization have greatly contributed to the emission of higher amount of heavy metals such as cadmium,nickel,and lead into the environment.These metals are non-biodegradable and toxic,causing much effects on plants and by extension to animals and humans,which have become a major global concern.The inherent ability of plants to resist heavy metal toxicity seems to be the most sustainable and cost-effective strategy.Castor plant is widely studied due to its tolerance to the effects of heavy metal contaminated soils,owing to its large biomass content and high accumulating capacity.Castor plants to some extent can tolerate elevated levels of heavy metals through several developed mechanisms,such as activation of antioxidant enzymes,exclusion,accumulation of proline,compartmentalization,organic acid exudation,and phytochelatins.Molecular studies have identified some stress-responsive to aid the tolerance of heavy metals in castor.Stress caused by heavy metal toxicity affects seedling growth,biomass,photosynthetic pigments,protein level,and nutrient uptake of castor plant.The response of castor,however,to these stresses differs among cultivars,metal type and concentration,and time of metal applied.This review aims to summarize the physiological responses and various defense mechanisms of castor to tolerate and eradicate heavy metal toxicity and some stress-responsive genes identified at transcriptional and posttranscriptional levels that confer metal tolerance in this plant.

Construction ofcastorfunctionalmarkers fingerprint andanalysis of geneticdiversity

In order to provide a molecular basis for selecting good hybrid combinations for the identification of castor bean germplasm resources,fingerprint and genetic diversity analysis of 52 castor bean materials from 12 regions in 5 countries were constructed by using the Functinal Markers(FMs)associated with fatty acid metabolism-related genes.A total of 72 alleles were amplified by 29 pairs of FMs with an average of 2.483 per marker and the polymorphic information content was 0.103–0.695.Shannon’s information index(I),observed heterozygosity(Ho)and expected heterozygosity(He)were 0.699,0.188 and 0.436 respectively.The clustering results indicated that the castor germplasm could be divided into two groups with the genetic similarity coefficient of 0.59.The genetic similarity of 12 regions ranged from 0.518 to 0.917 and the genetic distance was between 0.087 and 0.658.A total of 5 pairs of core primers were screened to construct a digital fingerprint of different castor germplasm resources,which could distinguish all 52 germplasms.This study provides a scientific basis for screening high-quality castor germplasm resources and broadening the genetic basis of castor breeding at the molecular level.

蓖麻骨干亲本杂种优势群的划分

为提高蓖麻种质的鉴别和利用效率,本研究利用简单重复序列标记(simple sequence repeats,SSR)对来自10个国家15个地区的101份蓖麻骨干亲本材料进行了杂种优势群的划分。结果显示:58对SSR标记在101份蓖麻骨干亲本材料中共检测出328个等位基因,平均每个位点的等位基因数为5.655个;Shannon’s信息指数(I)的范围为0.916~1.939,平均值为1.469;平均多态性信息含量(PIC)为0.732,变幅为0.377~0.894。有效等位基因数(Ne)、观测杂合度(Ho)和期望杂合度(He)分别为3.941、0.817和0.732。利用UPGMA方法在遗传相似系数为0.462时将101份蓖麻骨干亲本划分为5个大群8个亚群。分群结果显示,大部分试验材料表现出很强的地域性,来自同一个国家或地区的材料往往聚为一类。来自15个不同地区蓖麻材料的群间遗传距离介于0.122~0.936,平均为0.508,遗传一致度在0.312~0.885范围内,平均为0.606。其中,来自广东和山东的蓖麻材料的遗传距离最小,遗传一致度最高,亲缘关系较近。本研究在分子水平上为蓖麻亲本选配等工作提供了科学依据。