Difference In Tolerance To Potassium Deficiency Between Two Maize Inbred Lines

Abstract

Northeast China Produces An Abundance of Maize (Zea Mays L.), and Improvement of Maize Yield At This Region Correlates Closely With Ensure Food Supply Safely of China. in Recent Years, Deficiency Or Relative Deficiency of Potassium (K) in The Soil Is An Important Limitation To Maize Production. Maize inbred Lines Tolerant To K Deficiency (T) and Sensitive To K Deficiency (C) Were Hydroponically Grown in 1/2 Hoagland Solution To Study The Possible Mechanism of Maize Tolerance To Potassium Deficiency From Physiological Point of View. With The Reduction of K⁺ Concentration, Dw of The Plant Became Apparently Greater in T Than in C, The Symptom of Potassium Deficiency Advanced in C. Under K Deficiency, The Taproot Elongation increased and Root Top Ratio Decreased To A Greater Degree in C Than in T, C Had Fawer Lateral Roots. T Had A Stronger K⁺-Uptake Ability Than C, and The Difference Was More Obvious in Culture Solution With A Lower K⁺ Concentrations of Culture Solution. K⁺ Dependent H⁺ Extrusion From The Root Treated With K⁺ Deficiency Was Larger in T Than in C.     

Effects of Various Phytohormones On Haploid Wheat Production in Wheat x Maize Crosses

Abstract

The Effects of Phytohormones On The Production of Haploid Wheat Were Examined in The intergeneric Crosses Between Japanese Wheat Cultivar (Triticum Aestivum Cv. Zenkojikomugi) and Maize (ZEA MAYS Cv. Pioneer P80 Lisa). The Detached Wheat Spikes Pollinated With Maize Were Cultured in A Solution Containing Sucrose and Sulfurous Acid Supplemented With 2,4―Dichlorophenoxyacetic Acid (2,4―D), indole-Acetic Acid, Naphthalene Acetic Acid, Kinetin Or 6-Benzylaminopurine At 0, 0.1, 1, 10, 100 Or 1000 Mg L-¹. Haploid Embryos Obtained Were Cultured On Agarose-Solidified B5 Medium. The Frequency of Plant Regeneration Was Significantly Affected Only By The Treatment With 100 Mg L-¹ 2,4―D. Thus, The Detached Spikes Were Cultured in The Medium Containing 2,4―D At 0, 25, 50, 75, 100, 125, 150, 175, 200 Or 400 Mg L-¹. The Treatments With 50 Mg L-¹ 2,4―D increased The Embryo Size, But The Treatments With Above 75 Mg L-¹ 2,4―D inhibited The Development of The Embryo. The Percentage of Florets Developing into Haploid Plants Was increased By The Treatment With 100 Mg L-¹ 2,4―D. Therefore, The Concentration of 2,4―D in THe Spikes Treated With 2,4―D At 50, 100 and 150 Mg L-¹ WERe Measured By Gas Chromatography. The Concentration of 2,4―D in THE Seed Was increased To 9.24 Ppm By The Treatment With 100 Mg L-¹ 2,4―D, A Further increase of 2,4―D Concentration in The Medium Having No Effect. On The Other Hand, The Concentration of 2,4―D in The Glumes and Rachis increased Up To 12.72 and 41.55 Ppm By The TreatmenT With 100 and 150 Mg L-¹ 2,4―D, Respectively. The Treatments With 2,4―D At A Concentration Higher Than 100 Mg L-¹ inhibited Embryo Development. The Present Results Suggested That 2,4―D At The Concentrations From 50 To 100 Mg L-¹ Would Be Optimum For Haploid Wheat Production Using Maize.     

The Contribution of Polyphenols To Antioxidative Activity In Common Buckwheat and Tartary Buckwheat Grain

Abstract

We Examined The Contribution of Polyphenols To The Antioxidative Activity In The Grains of Common Buckwheat “Hitachi Akisoba” (H) and “Kanto No.1” (K) and In Those of Tartary Buckwheat “Rotundatum” (R) and “Pontivy” (P). The Antioxidative Activity In The 80% Ethanol Extracts Was 16.4 and 15.3 ?Mol-Trolox G-¹ Dw In H and K, Respectively, and 52.9 and 57.4 µMOL-TROLOX G-¹ Dw In R and P, Respectively. These Extracts Were Analyzed By Hplc. In Common Buckwheat, (-)-Epicatechin, (-)-Epicatechingallate, and Rutin Were Confirmed. The (-)-Epicatechin Content Was 20.2 and 15.6 Mg 100 G-¹ Dw, and Those of Rutin Were 13.6 and 12.2 Mg 100 G-¹ Dw In H and K, Respectively. (-)-Epicatechin Accounted For About 13 and 11% of The Total Antioxidative Activity In H and K, Respectively, and Rutin About 2% In Both Varieties. Since Each Polyphenol Accounted For Only About One Fifth of The Total Antioxidative Activity, The Existence of Unknown Antioxidants Was Suggested. In Tartary Buckwheat, Rutin Quercitrin, and Quercetin Were Confirmed. The Rutin Content Was 1808.7 and 1853.8 Mg 100 G-¹ Dw, In R and P, Respectively. Rutin Accounted For About 90 and 85% of The Total Antioxidative Activity In R and P, Respectively. Accordingly, Rutin Appears To Be The Major Antioxidant In Tartary BuckwheaT.     

大麦EMS突变群体的创建及功能评价

为开展麦类作物功能基因组学研究,选用综合性状突出的大麦品种Tamalpais,通过化学诱变剂甲基磺酸乙酯(Ethyl methane sulfonate,EMS)处理,创建了含有10 389个M2单株的突变群体。该群体数据分析表明,温室条件下,6.21%的M2幼苗呈现叶片颜色变异;大田实验中,M2群体出现丰富的表型变异,主要包括幼苗匍匐、分蘖、株高、生育期、叶色、叶形、叶条纹、叶斑、穗部特征、育性等,其中幼苗匍匐、分蘖、株高、叶色、叶条纹、叶斑的突变频率分别为0.11%、6.03%、0.13%、2.5%、0.18%、0.17%。抽样调查显示,M2世代的胚坏死率较低,仅有9%左右的单株表现出过半的胚坏死率。运用TILLING技术成功获得大麦COI1同源基因的突变体,筛选结果同时表明,该突变群体的突变频率约为平均每673kb一个点突变。因此,Tamal-pais群体突变表型丰富、TILLING检测可行,可作为麦类作物基因图位克隆与功能验证的重要素材,适用于麦类作物的正向和反向遗传学研究。     

Assessing the tolerance toGlobodera pallida of resistant potato genotypes by means of field and pot tests

Summary The tolerance toGlobodera pallida of 15 potato genotypes with a high level of resistance toG. pallida was assessed by measuring their tuber yield in heavily infested fields and in nematicide treated strips in the same fields. Tolerance was also assessed in pots in the glasshouse by measuring the total biomass after 35 and 70 days growth in heavilyG. pallida infested soil and in uninfested soil. Large differences in tolerance between the genotypes were observed. High correlations were observed between tolerance assessments made in the field experiments and between field and pot experiments. No relationship was found between tolerance and maturity. Shoot and root dry weight were about equally affected by the nematode.     

Effect of Waterlogging During Vegetative Stage On Growth And Yield in Supernodulating Soybean Cultivar Sakukei 4

Abstract

The Supernodulating Soybean Cultivar Sakukei 4 Was Previously Characterized By Its Superior Capabilities of Nitrogen (N) Fixation and Photosynthesis, and Was Expected To Be High Yielding. Since The N Absorption By Sakukei 4 Is Largely Dependent On N Fixation, It May Be Strongly Affected By Waterlogging During The Vegetative Stage, Which Occurs Frequently in Major Soybean Producing Areas. in This Study, We investigated The Reduced Growth and Yield Resulting From Waterlogging DuringVegetative Stage and The Subsequent Recovery in Sakukei 4, in Comparison With Those in The Normally-Nodulating Cultivar Enrei and Non-Nodulating Genotype En1282. Under The Field Conditions, The Reduction of Growth and Yield By Waterlogging Was Greatest in En1282 Among The Three Genotypes, indicating That Capability of N Fixation Is Essential For The Recovery From Waterlogging-induced injury. The Waterlogging-induced Yield Reduction in Sakukei 4 Resembled That in Enrei, Although Growth Reduction Was Greater in Sakukei 4 Than in Enrei. Irrespective of Cultivar, The Yield Was Associated More Closely With The Crop Growth Rate (Cgr) During The Post-Treatment Stage Than With That During The Waterlogging Treatment. in The Pot Experiments, Yields Positively Correlated With Both Above- and Underground Plant Parts Irrespective of Cultivar, Not Significantly, But Significantly With Root Dry Weights in Enrei and With Nodule Dry Weights in Sakukei 4. These Results indicate That Sakukei 4 Exhibits A Marked Decrease in Dry Matter Production By Waterlogging, But Yield Decrease Is Compensated To A Level Similar To That of Enrei Because of Its Enhanced Nodule Growth During The Recovery Stage.     

Tocotrienol and fatty acid composition of barley oil and their effects on lipid metabolism

Barley oil was extracted with hexane from the grain of a high oil waxy hull-les barley. Twelve male broiler chicks were fed corn-based diets with either 10% barley oil, 10% corn oil or 10% margarinead libitum for ten days. Total plasma cholesterol concentration of the chicks fed barley oil was 34% lower (p<0.05) than that of the chicks fed margarine. Plasma low density lipoprotein cholesterol concentration of chicks fed barley oil was 53% and 59% lower (p<0.05) than those of chicks fed corn oil and margarine, respectively. Plasma high density lipoprotein cholesterol and triglyceride concentration of the barley oil group were similar to those of the margarine but higher (p<0.05) than those of the corn oil group. Chicks fed the barley oil gained more (p<0.05) body weight than those fed the corn oil and margarine. Barley oil had an effect in suppression of TC and LDLC in chicks compared to margarine. Barley oil supressed LDLC but not HDLC in chicks compared to corn oil. A greater weight gain of the chicks fed barley oil suggested that these chicks had normally functioning digestion and absorption. -Tocotrienol and -tocotrienol content of the barley oil were 24 and 17 times greater, respectively, than those observed in the corn oil, while the same fractions were not detectable in the margarine. Polyunsaturated fatty acid content of the barley oil was more than threefold that of margarine. These data suggest that -tocotrienol and polyunsaturated fatty acids are hypocholesterolemic components in barley oil.Contribution No. J-2617, Montana Agricultural Experiment Station. This research was supported, in part, by grants from the Montana Wheat and Barley Committee, Great Falls, MT and Ross Laboratories, Columbus, OH.     

Effect of season and cutting frequency on root and shoot competition between Festuca pratensis and Dactylis glomerata

Abstract Plant competition strongly affects the species composition of managed grassland. To identify relevant processes, Festuca pratensis (Huds.) and Dactylis glomerata (L.) were grown as monocultures or mixtures in boxes placed in the field for two seasons and subjected to two cutting frequencies. Root and shoot competition effects were separated using soil and aerial partitions. Shoot competition was analysed by measuring the vertical distribution of the leaf area and root competition by analysing the absorption of tracers. Values of relative yield indicated that the two grasses fully competed for the same limiting resources under the experimental conditions. The competitive ability of F. pratensis was lower during both years relative to D. glomerata. This was mainly related to its consistently lower shoot competitive ability, which was associated with less leaf area in the upper layers of the canopy and shorter leaves. Root competitive ability of F. pratensis changed with season. It was similar to that of D. glomerata during spring and autumn, but less during summer. The lower root competitive ability in summer might be due to the lower root activity of F. pratensis, measured as rubidium (Rb) and strontium (Sr) absorption in July, 0·1 and 0·2 m below the ground. Cutting frequency did not greatly influence the relative importance of root and shoot competition during the first growing season. However, under infrequent defoliation, the competitive ability of F. pratensis decreased markedly in full competition during the second growing season. These results suggest that distinct differences in the canopy structure and root activity of different plant species can affect the relative importance of root and shoot competition during the season.     

Assessing Drought Tolerance of Snap Bean (Phaseolus Vulgaris) From Genotypic Differences In Leaf Water Relations,Shoot Growth and Photosynthetic Parameters

Abstract

The Leaf Water Relations, Photosynthetic Parameters and Shoot Growth of Five Snap Bean Cultivars Were Assessed During The Drought Period To Determine Their Role In Alleviating Plant Water Deficit Imposed By Withholding Irrigation At Flowering. Soil Water Content of Irrigated Plants Was 18-20% While That of Unirrigated Plants Was 6-10% At 60 Days After Seeding (Das). Leaf Water Potential Was Approximately 0.15Mpa Lower and Relative Water Content Was Approximately 5% Lower In Unirrigated Plants Than In Irrigated Plants At 57 Das. Unirrigated Plants Had A Lower Stomatal Conductance (G_s) and Intercellular Co₂ Concentration (C_i). Reduced Leaf Water Potential and Relative Water Content Were Associated With A Decreased Stem Elongation Rate. Plants With A Lower Stem Elongation Rate Had A Higher Specific Leaf Weight and Succulence Index (Suci). Significant Differences Among Five Cultivars of Snap Bean Were Found For All Parameters Measured. Decreased Leaf Water Potential and Stem Elongation Rate Resulting From Drought Participated In Preserving Relative Water Content and Improving Specific Leaf Weight and Suci. Maintenance of Higher Relative Water Content Increased G_s and C_i. Cultivars That Maintained A High Relative Water Content When Leaf Water Potential and Stem Elongation Rate Were Decreased Markedly, Were More Tolerant To Drought Than Those Which A Reduced Relative Water Content and The Leaf Water Potential and Stem Elongation Rate Were Only Slightly Lowered. Reduced Yield (Pods Per Plant and Seed Biomass) Resulting From Drought Was Associated With Reduced Relative Water Content.     

小麦黄矮病抗性基因及其鉴定研究进展

小麦黄矮病是由大麦黄矮病毒(BYDV)引起的小麦主要病害之一。本文综述了小麦BYDV的主要抗性基因及其鉴定方法、微克隆和微分离的研究进展，并对其形态学标记、生化标记、细胞学分析和分子标记鉴定方法的原理及应用作了比较分析。本文最后还提出了目前研究中存在的问题及其未来研究的方向。     

Water Acquisition From The Seasonal Wetland and Root Development of Pearl Millet Intercropped With Cowpea in A Flooding Ecosystem of Northern Namibia

Abstract

Seasonal Wetlands, Locally Called Oshanas, Are Characteristic of The Densely Populated Northern Namibia, A Desert Country in Southwest Africa. The Formation of Seasonal Wetlands, Which Will Sustain The Water Balance of A Semiarid Environment, Was Quite Unstable Depending Entirely On The Variable Rainfall in The Upper Catchments of Angola. The Objective of The Present Study Was To Evaluate The Use of Seasonal Wetland Water By Pearl Millet, The Local Staple Food Crop intercropped With Cowpea, To Discuss The Water Competition Pattern of intercropped Species. Root System Development of The intercropped Species Was Also Evaluated Together With The Water Source Analysis. For This Purpose, Field Experiments Using Pearl Millet intercropped With Cowpea in The Seasonal Wetland in Namibia University (Exp. 1) and Monocropped Pearl Millet in The Local Farmers Field (Exp. 2) Were Conducted in Northern Namibia. Both Pearl Millet and Cowpea Developed Deeper Root Systems As The Distance From The Seasonal Wetland Water increased. At Flowering Time, The δD Value of intercropped Cowpea Was Similar To That of Wetland Water, While That in Pearl Millet Was Much Lower Than Those of Both The Wetland Water and Groundwater. This indicated That intercropped Pearl Millet Did Not Have Full Access To The Wetland Water When There Was Competition With Cowpea For Water Derived From Various Water Sources. Under Such Circumstances, intercropped Pearl Millet Probably Relies More On The Rainfall Water, Which Is Just Sufficient To Sustain Its Growth in A Semiarid Environment. By Contrast, intercropped Cowpea Wins in The Competition With Pearl Millet and Can Acquire Water From The Existing Stored Wetland Water.     

Effects of Temperature on Growth and Dry Matter Accumulation in Mulberry Saplings

abstract

Prediction of mulberry (Moms alba L. cv. Shinn-ichinose) growth is necessary to cope with recent trends in mulberry cultivation. To develop a mulberry growth model, I investigated the response of mulberry growth to temperature. Mulberry saplings were grown in 1995 and 1996 at four constant (20, 24, 28, 32°C) and one diurnally fluctuating (32/24°C -mean 28°C) temperature conditions for 50-60 days in phytotrons under natural sunlight. Shoot length and leaf number were measured every 10 days during the temperature treatment and the dry matter of each plant part was measured at the end of the treatment period. Shoot length and leaf number increased exponentially with time at all temperatures examined, and these values increased with the increase in temperature. Shoot dry weight, over the period of the treatment, increased with temperature but the dry weights of stump and root were not affected by temperature. The optimum temperature for mulberry growth and dry matter accumulation was approximately 32°C.     

Simulation of water use and production of potatoes as affected by soil compaction

Summary The SWACRO simulation model was used to calculate water balances and associated potatotuber productions in a loamy sand soil with different types of compaction. Results for a noncompacted soil were compared with those for soils with a strong ploughpan and those with compacted surface soil. Input data consisted of: (1) measured hydraulic conductivity and moisture retention data for major soil horizons, (2) measured rooting depths and water-table levels, (3) calculated potential transpiration according to the modified Penman equation and (4) measured precipitation. Root extraction of water was simulated by two approaches, comparing the Feddes and Hoogland et al. extraction terms. The former procedure yielded best results in this study. The SWACRO model yielded good predictions of the soil water regime and tuber productions for the three treatments in the dry year 1976. A sensitivity analysis indicated that variations of water-use efficiencies did not significantly affect thedifferences in crop productions observed. Formerly: Soil Survey Institute, P.O. Box 98, 6700 AA Wageningen, the Netherlands.     

Genetic Variation of Zoysia As Revealed By Random Amplified Polymorphic Dna (Rapd) and Isozyme Pattern

Abstract

One Hundred and Thirty One Clones of Zoysia Spp. Collected From 59 Sites on The Coasts of Taiwan and Its Neighboring Islets Were Analyzed Using Both Random Amplified Polymorphic Dna (Rapd) and Isozymes To Reveal Their Genetic Variation. In The Rapd Analysis With 12 Primers, A Total of 92 Polymorphic Bands Which Could Distinguish 131 Genotypes Were Found. There Were 19 Polymorphic Bands and 81 Zymogram Patterns For Esterase, and 9 Bands and 10 Patterns For Acid Phosphatase, Respectively. Cluster Analysis By The Unweighted Pair-Group Method With Arithmetic Means (Upgma) of Rapd Data Indicated That Clones Collected From The Same Geographic Region Were Clustered Together. However, Isozyme Data Showed Discordant Patterns. Interestingly, Both Rapd Data and Isozyme Fingerprinting Revealed Less Correlation With The Intuitive Taxonomic Classification of Tested Clones, But More Related To The Specific Adaptation To The Geographic Or Geologic Aspects of Their Habitats.     

植物热激转录因子及其与耐热性关系的研究进展

热激转录因子是高等植物热胁迫响应基因转录水平上的中心调控蛋白,在植物的热胁迫信号转导以及耐热性中起着关键作用。为了给作物耐热性研究和应用提供有益的参考,本文从热激转录因子家族基因的分类、克隆、功能分析及其作用机理等方面详细介绍了模式植物拟南芥以及番茄、水稻、玉米和小麦等主要作物中该家族基因与耐热性关系的研究现状,并对该家族基因研究中亟待解决的问题进行了探讨。     

Reconciliation of D-genome puroindoline allele designations with current DNA sequence data

Kernel texture is an important trait in cereals, especially wheat (Triticum spp.). Throughout the Triticeae, the puroindoline genes act to soften kernel endosperm. Absence or mutation of either or both of the two puroindolines, ‘a’ and ‘b’, in Triticum aestivum results in harder grain texture. Apparently only one puroindoline haplotype was contributed by the Aegilops tauschii variety that contributed the D-genome during allopolyploidization. Yet, world collections of Ae. tauschii exhibit a range of puroindoline sequence polymorphisms. Consequently, these genes, through synthetic hexaploids (× Aegilotriticum) can enrich the wheat gene pool. Lastly, the puroindolines represent a useful tool for phylogenetic analyses. Here we review original sequence data published and/or available in public databases to reconcile the known gene sequence polymorphisms with a systematic approach to the designating of puroindoline gene and allele symbols in T. aestivum, Ae. tauschii, and × Aegilotriticum. This system follows the recommendations adopted by the International Wheat Genetics Symposium and described in the Catalogue of Gene Symbols for Wheat. Errors, discrepancies and ambiguities in the puroindolines are reviewed; a reconciliation of all existing data is outlined.     

Characterization of the effect of high salinity on roots of Chloris gayana Kunth: carbohydrate and lipid accumulation and growth

Branched nodal roots comprise the largest portion of the root system mass in Chloris gayana Kunth and the effects of high salinity on nodal root appearance and elongation rates were analysed in cv. Boma in greenhouse experiments. Roots from salt-treated plants (0·2 mol l^–1 NaCl) were smaller than controls, and accumulated higher concentrations of soluble sugars and reserve lipids. The number of nodal roots was reduced by the saline treatment. Leaf, tiller and nodal root appearance were delayed by salinity but the correlation among these processes was maintained, indicating that the developmental pattern was not altered by this level of salinity, only its rate. Initial nodal root growth rates varied as a function of plant size and were decreased by salinity only after 2 weeks of treatment. When shoots of non-salinized plants were cut, a drastic reduction in nodal root appearance was observed, suggesting emerging leaves were stronger sinks than roots for available reserves. However, when the shoots of salt-treated plants were cut, the already depressed root appearance rate was not further reduced. This suggests that, under salinity, alterations in root ability to metabolize reserves could have been more significant than reserve availability for controlling elongation.     

小麦光周期基因在我国不同麦区中的组成分布

为明确光周期基因在我国小麦品种中的组成分布特点,利用已有的特异性分子标记对我国977份小麦品种的光周期基因Ppd-A1、Ppd-B1和Ppd-D1进行检测,分析比较不同麦区中光周期基因的组成分布特点。结果表明,在Ppd-A1位点有5份材料无PCR扩增条带(0.5%),其余972份材料都为光周期敏感型Ppd-A1b(99.5%);在Ppd-B1位点仅青春37为光周期不敏感型Ppd-B1a(0.1%),有3份材料无PCR扩增条带(0.3%),其余973份材料为光周期敏感型Ppd-B1b(99.6%);在Ppd-D1位点有789份材料为光周期不敏感型Ppd-D1a(80.8%),其余188份材料为光周期敏感型Ppd-D1b(19.2%)。在东北春麦区、新疆冬春兼播麦区、青藏春冬兼播麦区等高纬度麦区,小麦品种多携带光周期敏感型基因Ppd D1b;在北部冬麦区、黄淮冬麦区、长江中下游冬麦区,不敏感型Ppd-D1a基因分布频率较高;Ppd-D1a基因分布频率总体呈现以黄淮冬麦区为最高,向其他方向麦区呈现下降的趋势。在Ppd-A1位点和Ppd-B1位点发现的无PCR扩增条带的新等位变异,丰富了小麦育种种质资源的多样性,为选育适应不同环境条件的品种奠定了材料基础,是进一步研究的重要材料。     

Stability of Rice Pollination in The Field Under Hot And Dry Conditions in The Riverina Region of New South Wales,Australia

Abstract

Even Under Extremely Hot (40ºC) Conditions During Anthesis, Heat-induced Floret Sterility Does Not Appear To Be A Serious Issue For Australian Rice Growers. This Contradicts Previously Reported Temperature Thresholds For Floret Sterility. To Determine The Factors Associated With Stable Rice Production Under Hot and Dry Conditions in The Riverina Region of New South Wales (Australia), We Examined Rice (Cv. ‘Langi’) Pollination At Different Distances From The Windward Edge of A Paddy Field and Its Association With Canopy Microclimate. With An Air Temperature of 34.5ºC and A Relative Humidity of 20.7% During Anthesis, Poor Pollination of Florets Occurred At The Windward Edge, But Pollination Remained Stable Farther From The Edge. The Temperature Difference Between The Air and The Panicles in The Canopy Reached As High As 6.8ºC Under These Conditions Because of Low Humidity and Strong Transpirational Cooling. Moreover, The Length of The Dehiscence At The Base of The Thecae During Anthesis Was Long; This Is A Desirable Trait For Heat Tolerance. The Long Basal Dehiscence of The Thecae of This Cultivar and The Lower Panicle Temperatures Relative To The Ambient Temperature Caused By High Transpirational Cooling Appear To Be The Key Factors Responsible For Stable Pollination Under The Extremely High Temperatures of The Riverina Region.     

Somatic embryogenesis and regeneration of five multipurpose cassava landraces extensively integrated in African cropping system

Successful development and adoption of transgenic cassava (Manihot esculenta Crantz) varieties in Africa depend on in vitro regeneration of landraces because of their agronomic value and amenability to genetic modification. The study investigated somatic embryogenesis from axillary bud and immature leaf-lobe explant and regeneration via shoot organogenesis in five cassava landraces. Landraces exhibited significant (P < 0.05) differences in frequencies of primary somatic embryo production, number of embryos per explant, and frequency of secondary embryos. The frequency of primary somatic embryogenesis ranged from 7.8 to 14.5%, whereas the number of embryos per explant varied from 5.3 to 10.6. However, only frequency of primary somatic embryos and number of embryos per explant showed significant (P < 0.05) differences when immature leaf lobe was used as explant. The frequency of primary somatic embryogenesis ranged from 42.7 to 49.2%, whereas number of embryos per immature leaf-lobe explant varied from 9.5 to 15.2 per explant. Secondary embryogenesis was cultivar-independent in the case of immature leaf-lobe explant. Cyclic and green (mature) embryogenesis showed no significant (P < 0.05) landrace differences in both axillary bud and immature leaf-lobe explants. Shoot regeneration from cotyledon of somatic embryos had significant (P < 0.05) landrace differences. The mean shoot-bud formation frequency of axillary bud and immature leaf-lobe explants was 51.4% and 37.2%, respectively. Root formation was efficient, with greater than 70% of shoots forming root in all landraces. Similarly, landrace differences were detected for the survival of acclimatized regenerated plants, with a mean of 94.7% for both explants. In conclusion, somatic embryos were produced from immature leaf and axillary bud explants of the landraces and the embryos were converted to plantlets via shoot organogenesis.