小麦成熟胚无性系后代的性状表现

观察了来源于小麦成熟胚培养再生植株中R_2代无性系农艺性状的变异。结果表明;R_2无性系的株高、穗粒数、千粒重、抽穗期和穗长都发生了不同变异,每个农艺性状的变异频代率较高,并且穗系间也有变异,还对无性系的变异和利用进行了讨论。     

60Co-γ射线诱变连麦2号M3代主要农艺性状的变异及多元分析

用60Co-γ射线诱变小麦连麦2号,对M3代292个穗行进行了主要农艺性状的变异及多元分析.结果表明:各性状的变异幅度是不同的,变异系数从大到小依次为:穗数＞千粒重＞穗长＞小穗数＞株高＞行粒重＞退化小穗数＞穗粒数＞穗粒重;变异率从大到小依次为:穗数＞千粒重＞株高=行粒重＞穗粒数＞穗长＞穗粒重＞小穗数＞退化小穗数.穗数、...     

小麦体细胞无性系矮秆变异体AS34株高构成和育种潜力探讨

创制和利用矮秆资源对于小麦品种改良具有重要意义。到目前为止,在小麦属中虽然已鉴定了多个矮秆资源,但多数矮秆资源在小麦中的利用价值有限。本研究对利用无性系变异途径获得的小麦矮秆材料AS34及其与模式小麦品种中国春杂交F1、F2材料进行了株高构成和主要农艺性状分析。结果发现,AS34共有4个节间,比其野生型豫麦66少了1个节间,各个节间长度按相似比例缩短,穗下节长度短于第2节长度;F1株高、节间长度指数介于2个亲本之间,节数与AS34相同,穗长、小穗数、穗粒数超过2个亲本;F2株高、穗长、穗粒数、小穗数变异范围广泛,约70%植株株高为60~89 cm,穗长6.0~9.9 cm、穗粒数50~79粒、小穗数20~24个。结果表明,AS34的矮秆变异由多基因控制,表现为数量性状,其矮秆性状对杂交后代穗长、小穗数、穗粒数等主要农艺性状有正向遗传效应,F2选择穗大、粒多、株高适中优良单株的机率较大,具有很好的育种利用价值。     

EMS对三个玉米自交系的诱变效应分析

EMS诱变玉米花粉是玉米化学诱变的主要技术。该研究以生产上3个常用的玉米自交系K305、21-ES、R08为材料,对其花粉用不同浓度的EMS诱变处理,探讨其EMS诱变的最佳浓度范围,明确其诱变效应。结果表明：3个自交系经过不同浓度的EMS诱变后,其结实率随着浓度的增大表现出减小的趋势,从其半致死剂量来看,EMS诱变花粉的适宜浓度范围自交系K305和R08均为0.67~1.0 mL?L-1,21-ES在1.67 mL?L-1附近。 M1代不同性状其变异幅度和变异系数与对照相比主要表现出增大的趋势,其不同性状的生物学效应在材料间表现不一致,表明性状在不同材料间对EMS的敏感性不一样,生育期表现为21-ES>K305>R08;主要株型性状表现为R08>21-ES>K305;主要雄穗性状K305和21-ES比R08敏感;主要果穗性状表现为21-ES>K305>R08。 M2代整体表现为变异谱扩大,其株高、穗位高和叶面积以及主要果穗性状的变异表现复杂,主要雄穗性状中除K305的M2株系雄穗分枝数呈双向变异外,其余M2株系整体偏向于雄穗变短,雄穗分枝数减小。该研究结果为后续研究和应用打下了基础。     

高蛋白小麦无性系

八十年代以来在多种植物组织培养物的再生植株中观察到体细胞无性系变异现象,并开始用于植物的品种改良。本工作以小麦花粉植株纯系为材料,经幼穗培养,诱导胚性愈伤组织,经8—10个月继代培养,得到大量再生植株(SC_1)。SC_1植株中约有30%表现性状变异,这些变异在SC_2代分离。一些 SC_1不变异的植株在 SC_2代中出现变异株。表明体细胞无性变异包括显性和隐性两类变异。变异的性状有:植株高度、成熟期、芒性、蜡质、穗形等。对     

海南疣粒野生稻DNA导入栽培稻及其后代的SSR验证

选取抗性较好且生长旺盛的海南疣粒野生稻,提取其基因组DNA,通过穗颈注射法将其导入杂交水稻恢复系R225、R128、R15。第1代开始选择在生育期、株高、株叶型和穗粒结构等性状与群体中其他单株有明显不同的变异株,经过3代选择,筛选到15份稳定材料。利用SSR分子标记检测4份导入后代材料具有供体而受体无的DNA条带,说明本试验获得了来自疣粒野生稻的变异材料。     

大豆航天搭载SP4选择效果与SP2代变异率相关分析

摘要：为了明确大豆航天搭载早期世代农艺性状选择的依据,提高航天搭载育种早期世代选择效果。对6个大豆品种经过航天搭载后的SP2代变异率和SP4代选择效果进行了分析,结果表明遗传力高的SP2代的单株荚数和单株粒数2个农艺性状的变异率与SP4代入选单株数相关达到极显著水平;SP2代遗传力较高底荚高度和节间长度的变异率与SP4代入选单株相关达到显著水平,SP2代遗传力不高的植株高度和主茎节数变异率与SP4代入选单株相关不显著;SP2代对单株荚数、单株粒数、底荚高度、节间长度进行选择有效,而对植株高度和主茎节数选择效果不明显。     

大豆航天搭载SP4代选择效果与SP2代变异率相关性分析

为了明确大豆空间诱变早期世代农艺性状选择的依据,提高空间诱变育种早期世代选择效果,对6个大豆品种经过航天搭载后的SP2代变异率和SP4代选择效果进行了分析,结果表明遗传力高的SP2代的单株荚数和单株粒数2个农艺性状的变异率与SP4代入选单株数相关性达到极显著水平;SP2代遗传力较高的底荚高度和节间长度的变异率与SP4代入选单株相关性达到显著水平,SP2代遗传力不高的植株高度和主茎节数变异率与SP4代入选单株相关不显著;SP2代对单株荚数、单株粒数、底荚高度、节间长度进行选择有效,而对植株高度和主茎节数选择效果不明显。     

普通野生稻（Oryza rufipogon）DNA导入栽培稻后代主要性状的遗传变异

通过花粉管通道法将普通野生稻(Oryza rufipogon)DNA导入宁夏水稻品种宁粳16号和宁粳23号中,获得外源DNA导入系(以D表示),选择的导入系经4次连续自交获得D4代材料.选择其中36个株系在北京种植,进行农艺性状调查和变异类型分析.结果表明,这些导入系分别在株型、生育期、分蘖力、株高、每穗粒数、每穗粒重、穗长、千粒重等性状上发生变异;一些导入系的每穗实粒数、每穗粒重、穗长、千粒重和分蘖数等明显高于受体,表现出高产潜力.本文着重阐述导入系的每穗实粒数、千粒重、分蘖数等与产量相关性状的遗传变异.     

基因枪法转化水稻E32后代非目标农艺性状变异的研究

采用基因枪法将4个抗真菌性病害基因(RAC22、RCH10、β-1,3-Glu和B-Rip)导入超级稻(Oryza sativa L.)恢复系E32中,经选择获得10个T4代转基因株系。分蘖盛期纹枯病抗性鉴定表明外源基因已在转基因株系中得到表达并获得抗性,这些转基因株系除了产生抗病性等目标性状的变异外,还发生生育期、植株形态、谷粒外观及产量性状等非目标农艺性状变异。对这些非目标性状进行遗传增益和稳定性分析表明,不同转化株系间或性状间的遗传增益均存在较大差异,其中遗传增益最高的性状是单株穗数、着粒密度和单株产量;各性状中以株高、穗长和谷粒外观性状的变异程度最低,单株穗数和千粒重的变异系数最大。通过选择可获得产量与品质性状均有提高的转基因水稻。     

QTL mapping analysis of plant height and ear height of maize (Zea mays L.)

Genetic map containing 103 microsatellite loci obtained on 200 F2 plants derived from the cross R15 x 478 was used for quantitative trait loci (QTL) mapping in maize. QTL were characterized in a population of 200 F2:4 lines, derived from selfing the F2 plants, and were evaluated with two replications in two environments. QTL determinations were made from the mean of these two environments. Plant height (PH) and ear height (EH) were measured. Using composite interval mapping (CIM) method, a total of 14 distinct QTLs were identified: nine for PH and five for EH. Additive, partial dominance, dominance, and overdominance actions existed among all detected QTL affecting plant height and ear height. The QTL explained 78.27% of the phenotypic variance of PH and 41.50% of EH. The 14 QTLs displayed mostly dominance or partial dominance gene action and mapped to chromosomes 2, 3, 4, 8 and 9.     

国内部分玉米地方品种的品质与农艺性状的表型多样性分析

以710份玉米地方品种为材料,采用随机区组设计,研究了其在脂肪、蛋白质与淀粉等品质性状以及株高、穗长等农艺性状上的表型多样性,分析了这些研究材料的表型多样性在地理来源上的分布.结果表明:(1)平均油分含量4.92%,达到高油3、2和1等级的材料各11、2和3份,地区间差异不显著;(2)平均蛋白质含量12.55%,96%的材料达到食用玉米1等级蛋白质舍量,地区间差异显著;(3)平均淀粉含量70.88%,所有材料均未达高淀粉玉米品种审定标准;(4)株高、穗位高和雄穗分枝数等3个植株性状的变异程度大,地区间差异显著,华南、西南和西北的植株高大,雄穗发达,而华北和东北的植株矮小,雄穗分枝数较少;(5)在3个果穗性状中,变异程度大小依次是穗长、穗行数和穗粗,地区间差异显著,筛选到长穗、粗穗和多穗行材料各5、1和3份;(6)不同地区和不同性状的多样性指数均有显著差异,以华南、华东和西南玉米材料的多样性水平较高.所有研究材料的表型多样性分析结果显示这些材料的脂肪与蛋白质含量较高,淀粉舍量较低;华南、华东和西南种质的多样性水平明显高于其他地区的种质.     

Quantitative trait loci analysis of plant height and ear height in maize (Zea mays L.)

Genetic map containing 103 microsatellite loci obtained on 200 F₂ plants derived from the cross R15 × 478 was used for quantitative trait loci (QTL) mapping in maize. QTLs were characterized in a population of 200 F_2:4 lines, derived from selfing the F₂ plants, and were evaluated with two replications in two environments. QTL determinations were made from the mean of these two environments. Plant height (PH) and ear height (EH) were measured. Using composite interval mapping (CIM) method, a total of 14 distinct QTLs were identified: nine for PH and five for EH. Additive, partial dominance, dominance, and overdominance actions existed among all detected QTLs affecting plant height and ear height. The QTLs explained 78.27% of the phenotypic variance of PH and 41.50% of EH. The 14 QTLs displayed mostly dominance or partial dominance gene action and mapped to chromosomes 2, 3, 4, 8, and 9. The text was submitted by the authors in English.     

Effect of in vitro culture conditions on somaclonal variation in cowpea (Vigna unguiculata Walp.) using RAPD markers

We report a high frequency regeneration protocol in cowpea (Vigna unguiculata Walp. var. C 152) via somatic embryogenesis from 10-d-old primary leaf explants. A study was conducted to examine the effect of somaclonal variations in in vitro derived cowpea plants under field conditions. The regenerated plantlets were successfully transferred to field after hardening in vitro and grown for collecting R0, R1 and R2 seeds. The seeds of R1 and R2 generations were subsequently, grown under field conditions and their various biometrical traits were compared and evaluated with non-tissue cultured cowpea plants as check. There was no detectable somaclonal variation induced in R0-R2 in any of the biometrical traits. The results indicate that the inclusion of different plant growth promoters at specified concentrations and duration in our earlier tissue culture work did not induce any detectable mutation. The RAPD analysis also shows that there is no genetic variation among R2 cowpea plants. The somatic embryogenesis protocol we report could thus be safely applied for high frequency true-to-type regeneration and transformations protocols without any somaclonal variation.     

Demographic response of plant populations to habitat fragmentation and temporal environmental variability

Many plant species currently exist in fragmented populations of different sizes, while they also experience unpredictable climatic fluctuation over time. However, we still understand little about how plant demography responds to such spatial and temporal environmental variability. We studied population dynamics of an understory perennial herb Trillium camschatcense in the Tokachi plain of Hokkaido, Japan, where a significant effect of forest fragmentation on seedling recruitment was previously reported. Four populations across a range of fragment sizes were studied for 6 years, and the data were analyzed using matrix population models. Per capita fecundity (the number of recruits per plant) varied greatly among populations, but the variation in population growth rates (λ) was mainly driven by the variation in stasis and growth rates, suggesting that the general trend of reduced fecundity in fragmented populations may not be readily translated into subsequent dynamics. Temporal variation in λ among years was more than 2 times larger than spatial variation among populations, and this result was likely attributable to the contrasting response of correlation structures among demographic rates. The among-population variation in λ was dampened by negative covariation between matrix elements possibly due to density-dependent regulation as well as an inherent constraint that some elements are not independent, whereas positive covariation between matrix elements resulted in large temporal variation in λ. Our results show that population dynamics responded differently to habitat fragmentation and temporal variability of the environment, emphasizing the need to discriminate these spatial and temporal variations in demographic models. Although no populations were projected to be declining in stochastic simulations, correlation between current habitat size and plant density implies historical λ is positively related to habitat size.     

Genetic and environmental factors reducing the incidence of the storage pest Sitotroga cerealella in maize

The Angoumois grain moth, Sitotroga cerealella (Olivier) (Lepidoptera: Gelechiidae), is found worldwide and infests maize grains in the field and during storage. Transgenic maize resistant to kernel attack by S. cerealella has been developed, but could pose a nutritional risk to humans and livestock. Therefore, alternative sources of resistance posing no threat to consumption should be identified. In this study, our main objectives were to assess genetic variability for kernel damage by S. cerealella under natural infestation and to determine genetic and environmental factors contributing to genotype, year, and genotype*year variability. Factorial regression was performed to obtain a biological explanation for the number of kernels damaged per ear. Seventy-seven Spanish maize landraces along with six hybrid checks were evaluated in 2004, 2005, and 2006. There was variability for kernel damage by natural infestation of S. cerealella among the landraces: popcorn landraces were among the least damaged, whereas hybrid checks were among the most susceptible genotypes. Plant characteristics associated with ear appearance could be the main stimulatory factors for oviposition and feeding of S. cerealella moths, followed by husk coverage of the ear. It was confirmed that temperature is the main environmental factor affecting S. cerealella development. Genotypes sensitive to infestation by S. cerealella were more negatively affected by higher temperatures than the least attractive genotypes, and lower temperatures reduced the number of kernels damaged on the most susceptible genotypes more than on the least susceptible.     

Geographic diversity cline of R gene homologs in wild populations of Solanum pimpinellifolium (Solanaceae)

Plant resistance (R) genes tend to be highly variable within plant species and are thought to be under natural selection; however, little is known about the geographic distribution of R gene diversity within and among plant populations. To determine the possible roles of demography and selection on R gene evolution, patterns of diversity at the multigenic Cf-2 R gene family were studied in Solanum pimpinellifolium populations along the northern coast of Peru. Population diversity levels of Cf-2 homologs follow a latitudinal cline, consistent with the species's history of gradual colonization of the Peruvian coast and population variation in outcrossing levels. Although previous evidence suggests that selection has shaped the DNA sequence content of the Cf-2 genes, current results imply that the geographic distribution of Cf-2 homolog diversity has been shaped primarily by demographic factors or by selective pressures with a clinal distribution.     

Aerobiology of subtropical Eastern Hymalayas (Kurseong), India

Summary Aerobiology studies of subtropical Eastern Hymalayas (Kurseong) were done for two years. A total of 32 airborne pollen types were recorded along with a few fern spores. In all 4961 pollen grains were trapped during 1981–82 and 4697 during 1982–83. The data reveals seasonal variation of pollen incidence. The incidence of tree pollen dominated over grasses and weeds. The trapped tree pollen originated fromAlnus, Betula, Engelhardtia, Quercus, Bucklandia, Acer, Salix, Ilex, Cryptomeria, Pinus, Cupressus, etc. among others, some of which are known to be allergenically significant in Kurseong. The pollen grains of weeds likeUrtica, Plantago, Cannabis, Rumex, Amaranthaceae, Chenopodiaceae etc. are also proved to be allergenically significant in Kurseong. Grass pollen grains established as highly allergenic, occurred in large amount round the year. The seasonal variation of pollen incidence was dependent mainly on variable flowering periods and climatic variations.     

Influence of plant species and environmental conditions on epiphytic and endophytic pink-pigmented facultative methylotrophic bacterial populations associated with field-grown rice cultivars

The total methylotrophic population associated with rice plants from different cultivars was enumerated at three different stages: vegetative, flowering, and harvesting. The bacterial population in the leaf, rhizosphere soil, endophytic in the stem and roots, and epiphytic in the florets and grains were determined from four rice cultivars, Il-mi, Nam-pyeoung, O-dae, and Dong-jin, sampled from three different field sites. The methylotrophic bacteria isolated on AMS media containing 0.5% methanol as the sole carbon source uniformly showed three distinct morphologies, which were recorded as separate groups and their distribution among the various samples was determined using the ecophysiological index. The growth stage at the time of sampling had a more significant effect on the methylotrophic population and their distribution than the field site or cultivar. A similar effect was also observed for the PPFMs, where their population in different plant parts increased from V10 to R4 and then decreased towards stage R9. A canonical discriminant analysis of the PPFM population from different parts of rice showed clear variations among the cultivars, sampled sites, and growth stages, although the variations were more prominent among the growth stages.