Microsatellite mapping of genes for semi-dwarfism and branched spike in Triticum durum Desf. var. ramosoobscurum Jakubz. “Vetvistokoloskaya”

A combination of increased harvest index and increased seed number per plant may improve wheat yield. We found an accession Triticum durum Desf. var. ramosoobscurum Jakubz. “Vetvistokoloskaya” R-107, whose plant height was short and spike was branched. To characterize R-107, we mapped the genes for semi-dwarfism and branched spike. Semi-dwarf gene Rht_R107 (Reduced height R107) from R-107 was allelic to Rht11 and Rht-B1b on chromosome 4BS. Rht_R107, as well as Rht11, was recessive and insensitive to gibberellic acid. Microsatellite mapping indicated that Rht_R107 was linked to Xwmc48 (1.2?cM) on chromosome 4BS, and Rht11 was also linked to Xgwm495 marker (19.4?cM) on chromosome 4BS. The locus responsible for branched spike in R-107 was mapped by genotyping three F₂ populations using microsatellite markers. Phenotypic analysis revealed that branched spike was under control of a recessive allele at a single locus. The bh (branched head) locus was located on chromosome 2AS and the marker Xgwm425 flanked the bh gene proximally.     

The third glume phenotype is associated with rachilla branching in the spikes of tetraploid wheat (<Emphasis Type="Italic">Triticum</Emphasis> L.)

We investigated the new inflorescence architectural character “three glumes” and a new status of ramification in tetraploid wheat. Using 9 tetraploid accessions with “turgidum type of branching”, the segregation of branched spike and the third glume indicated the complete linkage of genes for both phenotypes. The rachilla were elongated and bore florets at basal nodes while bearing spikelets at the apical nodes in T. durum Desf. TRI 9644 and T. turgidum L. PI 67339. The phenotype was different from “sham-ramification” in Triticum jakubzineri Udacz. et Schachm., with florets at basal and apical nodes of elongated spikelet rachilla. We confirmed a new status of ramification, “false-true ramification”. It was considered that the “false-true ramification” was determined by the shr2 gene in the long arm of chromosome 2A because the ramification of PI 67339 and TRI 9644 was supposed to be allelic. The segregation of “sham-ramification” and the third glume also indicated the complete linkage of genes for both phenotypes. Thus we concluded that the presence of third glume phenotype is associated with rachis and rachilla branching in the spikes of tetraploid wheat. The present study confirmed the existence of three distinct types of spike ramification, whose classification is not entirely unified: (a) “true ramification”—“branched spike”—“genuine branching”—“turgidum type of branching”, (b) “false ramification”—“pseudo-branched spike”—“sham ramification”—“vavilovii type of branching” and (c) “false-true ramification”.     

Microsatellite mapping of the genes for sham ramification and extra glume in spikelets of tetraploid wheat

The loci for expression of prolonged spikelet rachilla named ‘sham ramification’ in three tetraploid wheat accessions, two accessions of Triticum jakubzineri Udacz. et Schachm. (2n = 4× = 28, genome BBAA) ‘PI 585014’ and ‘R-101-03’ and one sample of Triticum turgidum L. (2n = 4× = 28, genome BBAA) ‘PI 67339’, were mapped by genotyping F₂ populations using microsatellite markers. The segregation analysis confirmed that sham ramification was controlled by recessive, epistatic genes, shr1 (sham ramification 1) and shr2 (sham ramification 2). The genotypes of ‘sham ramification’ were shr1shr1Shr2Shr2 for T. jakubzineri and Shr1Shr1shr2shr2 for T. turgidum (PI 67339). Normal rachilla was determined by Shr1Shr1Shr2Shr2. The shr1 gene and the gene for extra glume (exg) were completely linked; and, the shr1/exg gene complex was bracketed by the markers Xbarc319 and Xbarc232 on the long arm of chromosome 5A. In the F₂ of PI 67339/LD222 the gene shr2 was bracketed by Xwmc819 and Xwmc794 on the long arm of chromosome 2A.     

Exploration of glaucous variation in a collection of wild diploid wheat Triticum urartu Thumanjan ex Gandilyan

Glaucousness is the visible opaque-white or bluish-green wax which appears in plant cuticles. Although W1 and Iw1 loci on chromosome 2B mainly play a role to determine glaucousness/non-glaucousness trait in polyploid wheat, in the chromosome 2A of polyploid wheat, the non-glaucous inhibitor locus has not been reported. We explored the glaucous phenotypes for leaf, spike and stem in 274 accessions of Triticum urartu Thumanjan ex Gandilyan (2n?=?2x?=?14, genome A^uA^u), the A genome progenitor of polyploid wheat. The 272 accessions of T. urartu were non-glaucous for leaf, spike and stem. It was thought that non-glaucousness of T. urartu played an important role for plant adaptation throughout the Fertile Crescent. However, PI 662236 was glaucous in leaves, leaf sheaths and spikes, whereas PI 662271 was glaucous on the leaves and leaf sheaths, but non-glaucous in the spikes. Prior to heading PI 662236 and PI 662271 mimicked T. urartu by showing glaucous leaves and leaf sheaths. The plant form and somatic chromosome number indicated that PI 662236 and PI 662271 were tetraploid Triticum dicoccoides (Körn. ex Asch. & Graebn.) Schweinf. (2n?=?4x?=?28, BBA^uA^u genome). The occurrence of T. dicoccoides in the collections of T. urartu demonstrated that even famous botanists can make mistakes in identifying grasses. However, these mistakes lead to finding two rare types of T. dicoccoides with occurrence of glaucousness. The majority of T. dicoccoides that are non-glaucous. The genotype of PI 662236 was assigned as iw1iw1iw3iw3 for glaucousness and that of PI 662271 was iw1iw1Iw3Iw3 for the inhibitors for non-glaucous spikes.

     

The Odd–Even Behaviour of Dicarboxylic Acids Solubility in the Atmospheric Aerosols

The solubility and the enthalpy of dicarboxylic acids have been determined in water at intervals between 278.5 and 543.5 K. At 298.15 K, the values derived were: Δ_sol H _m (m?=?1.33 mol kg^?1)?=?29.80 kJ mol^?1for oxalic acid; Δ_sol H _m (m?=?16.03 mol kg^?1)?=?12.82 kJ mol^?1 for malonic acid; Δ_sol H _m (m?=?0.75 mol kg^?1)?=?28.20 kJ mol^?1 for succinic acid; Δ_sol H _m (m?=?8.77 mol kg^?1)?=?48.01 kJ mol^?1 and Δ_sol H _m (m?=?0.17 mol kg^?1)?=?40.30 kJ mol^?1 for glutaric and adipic acid respectively. The solubility value exhibits a prominent odd–even effect with respect to terms with even number of carbon atoms with the odd carbon numbers showing much higher solubility. Observations made in the atmospheres suggest that this odd–even effect may have implications for the relative abundance of these acids in aerosols.     

Short-term impact of a wildfire on net and gross N transformation rates

Wildfires often modify soil properties, including the N status and net N mineralization rates, but their impacts on gross N fluxes have been scarcely evaluated. We aimed to ascertain the immediate effects of a medium–high severity wildfire on soil N transformations. Net and gross N rates were analytically and numerically (FLUAZ) quantified in burned (BS) and unburned (US) topsoils from the temperate–humid region (NW Spain). Analytical and numerical solutions were significantly correlated for both gross N mineralization (m) (r ²?=?0.815; p?<?0.001) and gross nitrification (n) (r ²?=?0.950; p?<?0.001). In BS, all NH₄ ⁺-N fluxes (net m, gross m and gross NH₄ ⁺-N immobilization, ‘ia’) increased, while those of NO₃ ^?-N decreased (gross n and gross NO₃ ^?-N immobilization, ‘in’) or did not vary (net n). In US and BS, gross m (0.26–3.60 and 4.70–15.42 mg N kg^?1 day^?1, respectively) predominated over gross n (0.026–2.45 and 0.001–0.002 mg N kg^?1 day^?1, respectively), and the same was true for the net fluxes. Compared with the few available data on recently burned soils (m?=?8–55 mg N kg^?1 day^?1; n?=?0.50–1.83 mg N kg^?1 day^?1), our gross m and n rates were similar and very low, respectively; gross n showed that nitrifiers were active in US and also in BS, despite the 98 % reduction observed immediately after the fire. For gross fluxes, m increased more than ia suggesting an NH₄ ⁺-N accumulation, but there is no risk of NO₃ ^?-N leaching because n decreased more than in.     

The effect of soil-climate conditions on yielding parameters,chemical composition and baking quality of ancient wheat species Triticum monococcum L., Triticum dicoccum Schrank and Triticum spelt L. in comparison with modern Triticum aestivum L.

Triticum monococcum L., Triticum dicoccum Schrank and Triticum spelt L. nowadays offer an alternative to Triticum aestivum L. We analyzed grain and straw yield, yielding parameters, chemical composition and bakery quality of these species and compared them with modern T. aestivum at three sites with different soil-climate conditions. The average grain yield varied from 0.41 t ha^?1 (T. monococcum) to 5.17 t ha^?1 (T. aestivum), straw yield varied from 1.50 t ha^?1 (T. dicoccum) to 5.83 t ha^?1 (T. aestivum). The yielding parameters and chemical composition of the grain were significantly influenced by soil-climate conditions and wheat species. The highest average crude protein content was recorded in T. spelta (20.55%), while the lowest in T. aestivum (11.20%). The Zeleny’s sedimentation test ranged from 9.0 ml (T. monococcum) to 34.5 ml (T. aestivum) and the value of the Gluten index varied from 7.45 (T. dicoccum) to 89.75 (T. aestivum). According to the results, ancient wheat species provides lower grain and straw yields, higher protein content and mineral concentrations. Concentration of proteins and grain’s baking quality strongly depends on wheat species and soil-climate conditions.     

Nutrient Removal in Pilot-Scale Constructed Wetlands Treating Eutrophic River Water: Assessment of Plants, Intermittent Artificial Aeration and Polyhedron Hollow Polypropylene Balls

Seven experimental pilot-scale subsurface vertical-flow constructed wetlands were designed to assess the effect of plants [Typha latifolia L. (cattail)], intermittent artificial aeration and the use of polyhedron hollow polypropylene balls (PHPB) as part of the wetland substrate on nutrient removal from eutrophic Jinhe River water in Tianjin, China. During the entire running period, observations indicated that plants played a negligible role in chemical oxygen demand (COD) removal but significantly enhanced ammonia–nitrogen (NH₄–N), nitrate–nitrogen (NO₃–N) total nitrogen (TN), soluble reactive phosphorus (SRP) and total phosphorus (TP) removal. The introduction of intermittent artificial aeration and the presence of PHPB could both improve COD, NH₄–N, TN, SRP and TP removal. Furthermore, aerated wetlands containing PHPB performed best; the following improvements were noted: 10.38 g COD/m² day, 1.34 g NH₄–N/m² day, 1.04 g TN/m² day, 0.07 g SRP/m² day and 0.07 g TP/m² day removal, if compared to non-aerated wetlands without PHPB being presented.     

Treatment of Hydroponics Wastewater Using Constructed Wetlands in Winter Conditions

Hydroponics culture generates large amounts of wastewater that are highly concentrated in nitrate and phosphorus but contains almost no organic carbon. Constructed wetlands (CWs) have been proposed to treat this type of effluent, but little is known about the performance of these systems in treating hydroponic wastewater. In addition, obtaining satisfactory winter performances from CWs operated in cold climates remains a challenge, as biological pathways are often slowed down or inhibited. The main objective of this study was to assess the effect of plant species (Typha sp., Phragmites australis, and Phalaris arundinacea) and the addition of organic carbon on nutrient removal in winter. The experimental setup consisted of 16 subsurface flow CW mesocosms (1 m², HRT of 3 days) fed with 30 L?d¹ of synthetic hydroponics wastewater, with half of the mesocosms fed with an additional source of organic carbon (sucrose). Carbon addition had a significant impact on nitrate and phosphate removal, with removal means of 4.9 g m^-2?d^-1 of NO₃-N and 0.5 g m^-2 d^-1 of PO₄-P. Planted mesocosms were generally more efficient than unplanted controls. Furthermore, we found significant differences among plant treatments for NO₃-N (highest removal with P. arundinacea) and COD (highest removal with P. australis/Typha sp.). Overall, planted wetlands with added organic carbon represent the best combination to treat hydroponics wastewater during the winter.     

Physiological characteristics,gas exchange,and plant ion relations of quinoa to different saline groundwater depths and water salinity

The objective of this study was to investigate the influence of saline groundwater depths (SGDs) (0.3, 0.55, and 0.80 m) with salinity equivalent to irrigation water salinity (WS) and irrigation WS (10, 20, 30, and 40 dS m^?1) on physiological characteristics, gas exchange, and plant ion relations of quinoa in cylindrical lysimeters in greenhouse conditions. Root length density (RLD) in the soil layer close to the saline shallow groundwater decreased. Soil aeration was the key point for reduction in RLD by decreasing SGD that was intensified by the increase in WS. It is concluded that root of quinoa was sensitive to anaerobic soil conditions. Results showed that the mean value of leaf water potential (Ψ) dropped from ?1.53 to ?3.09 MPa by increasing WS from 10 to 40 dS m^?1. Increasing WS from the lowest to the highest level resulted in 48% decrease in leaf photosynthesis rate (A_n). Results revealed that leaf stomatal conductance (g_s) was more sensitive to salinity than A_n. Stomatal closure in quinoa started to occur when the Ψ value fell below approximately ?1.0 MPa. In general, increasing WS from 10 to 40 dS m^?1 resulted in about 4.6-fold, 2.1-fold, and 2.6-fold increase in plant Na⁺, Ca²⁺, and Cl^? concentration, respectively.     

Relationships between single tree canopy and grass net radiations

It is reported a simple approach to transform daily values of grass net (all-wave) radiation (R_n, MJ m⁻² day⁻¹), as measured over standard grass surface at meteorological stations, into whole tree canopy net radiation (A, MJ tree⁻¹ day⁻¹). The revolving Whirligig device [McNaughton, K.G., Green, S.R., Black, T.A., Tynam, B.R., Edwards, W.R.N., 1992. Direct measurement of net radiation and photosynthetically active radiation absorbed by a single tree. Agric. For. Meteorol. 62, 87–107] describing a sphere about the tree measured A in five trees of different species (walnut, dwarf apple, normal apple, olives and citrus), with leaf area L_A varying from 8.65 to 40 m². For each tree, A and R_n were linearly related (A = bR_n), as previously reported elsewhere, but it was found that the slope of such regression was also a linear function of L_A or, b = 0.303 (±0.032) L_A. Consequently, the hypothesis that total daily tree canopy net radiation per unit leaf area is linearly related to grass net radiation could not be rejected after 86 days of measurements in five locations, and the empirical relationship is A = 0.303 (±0.032) R_nL_A (R² = 0.9306).     

New sources of compact spike morphology determined by the genes on chromosome 5A in hexaploid wheat

Little is known about the relationship between compact spike loci in hexaploid wheat species. We studied two new compact spike mutants of common wheat Triticum aestivum L. (2n?=?6x?=?42, genome formula BBAADD). The new compact spike genes, C ⁷³⁹ of MCK 739 and Cp of near-isogenic line Mironovskaya 808 (Vrn1), were mapped using aneuploid stocks and microsatellite markers. The C ⁷³⁹ and Cp loci were distally linked with the microsatellite marker Xbarc319 in the F₂ populations of MCK 739?×?‘Novosibirskaya 67’ and Cp-Mironovskaya 808 (Vrn1)?×?‘Saratovskaya 29’. It was evident that the loci affecting compact spikes in T. aestivum mutants were located on chromosome 5AL distal from Q locus. These loci also affected to semi-dwarfism. We named this locus Cp1 (C ompact p lant 1) for all accessions. Cp1 was allelic to C ¹⁷⁶⁴⁸ gene located on the chromosome 5AL of tetraploid wheat [Triticum durum Desf. (2n?=?4x?=?28, genome formula BBAA)]. These dominant genes on chromosome 5AL will be utilized as new gene resources of compact spike morphology in hexaploid wheat. Relationship between loci Q and Cp1 was also discussed.     

Is CO2 evolution in saline soils affected by an osmotic effect and calcium carbonate?

Salt-affected soils are widespread, particularly in arid climates, but information on nutrient dynamics and carbon dioxide (CO₂) efflux from salt-affected soils is scarce. Four laboratory incubation experiments were conducted with three soils. To determine the influence of calcium carbonate (CaCO₃) on respiration in saline and non-saline soils, a loamy sand (6.3% clay) was left unamended or amended with NaCl to obtain an electrical conductivity (EC) of 1.0 dS?m^?1 in a 1:5 soil/water extract. Powdered CaCO₃ at rates of 0%, 0.5%, 1.0%, 2.5%, 5.0% and 10.0% (w/w) and 0.25-2 mm mature wheat residue at 0% and 2% (w/w) were then added. Cumulative CO₂-C emission from the salt amended and unamended soils was not affected by CaCO₃ addition. To investigate the effect of EC on microbial activity, soil respiration was measured after amending a sandy loam (18.8% clay) and a silt loam (22.5% clay) with varying amount of NaCl to obtain an EC_1:5 of 1.0–8.0 dS?m^?1 and 2.5 g glucose C?kg^?1 soil. Soil respiration was reduced by more than 50% at EC_1:5?≥?5.0 dS?m^?1. In a further experiment, salinity up to an EC_1:5 of 5.0 dS?m^?1 was developed in the silt loam with NaCl or CaCl₂. No differences in respiration at a given EC were obtained between the two salts, indicating that Na and Ca did not differ in toxicity to microbial activity. The effect of different addition rates (0.25–2.0%) of mature wheat residue on the response of respiration to salinity was investigated by adding NaCl to the silt loam to obtain an EC_1:5 of 2.0 and 4.0 dS?m^?1. The clearest difference between salinity levels was with 2% residue rate. At a given salinity level, the modelled decomposition constant ‘k’ increased with increasing residue addition rate up to 1% and then remained constant. Particulate organic carbon left after decomposition from the added wheat residues was negatively correlated with cumulative respiration but positively correlated with EC. Inorganic N (NH ₄ ⁺ -N and NO ₃ ^? -N) and resin P significantly decreased with increasing salinity. Resin P was significantly decreased by addition of CaCl₂ and CaCO₃.     

Effect of plant-mediated oxygen supply and drainage on greenhouse gas emission from a tropical peatland in Central Kalimantan,Indonesia

Abstract

To evaluate the hypothesis that plant-mediated oxygen supplies decrease methane (CH₄) production and total global warming potential (GWP) in a tropical peatland, the authors compared the fluxes and dissolved concentrations of greenhouse gases [GHGs; CH₄, carbon dioxide (CO₂) and nitrous oxide (N₂O)] and dissolved oxygen (DO) at multiple peatland ecosystems in Central Kalimantan, Indonesia. Study ecosystems included tropical peat swamp forest and degraded peatland areas that were burned and/or drained during the rainy season. CH₄ fluxes were significantly influenced by land use and drainage, which were highest in the flooded burnt sites (5.75 ± 6.66 mg C m^?2 h^?1) followed by the flooded forest sites (1.37 ± 2.03 mg C m^?2 h^?1), the drained burnt site (0.220 ± 0.143 mg C m^?2 h^?1), and the drained forest site (0.0084 ± 0.0321 mg C m^?2 h^?1). Dissolved CH₄ concentrations were also significantly affected by land use and drainage, which were highest in the flooded burnt sites (124 ± 84 μmol L^?1) followed by the drained burnt site (45.2 ± 29.8 μmol L^?1), the flooded forest sites (1.15 ± 1.38 μmol L^?1) and the drained forest site (0.860 ± 0.819 μmol L^?1). DO concentrations were influenced by land use only, which were significantly higher in the forest sites (6.9 ± 5.6 μmol L^?1) compared to the burnt sites (4.0 ± 2.9 μmol L^?1). These results suggest that CH₄ produced in the peat might be oxidized by plant-mediated oxygen supply in the forest sites. CO₂ fluxes were significantly higher in the drained forest site (340 ± 250 mg C m^?2 h^?1 with a water table level of ?20 to ?60 cm) than in the drained burnt site (108 ± 115 mg C m^?2 h^?1 with a water table level of ?15 to +10 cm). Dissolved CO₂ concentrations were 0.6–3.5 mmol L^?1, also highest in the drained forest site. These results suggested enhanced CO₂ emission by aerobic peat decomposition and plant respiration in the drained forest site. N₂O fluxes ranged from ?2.4 to ?8.7 μg N m^?2 h^?1 in the flooded sites and from 3.4 to 8.1 μg N m^?2 h^?1 in the drained sites. The negative N₂O fluxes might be caused by N₂O consumption by denitrification under flooded conditions. Dissolved N₂O concentrations were 0.005–0.22 μmol L^?1 but occurred at < 0.01 μmol L^?1 in most cases. GWP was mainly determined by CO₂ flux, with the highest levels in the drained forest site. Despite having almost the same CO₂ flux, GWP in the flooded burnt sites was 20% higher than that in the flooded forest sites due to the large CH₄ emission (not significant). N₂O fluxes made little contribution to GWP.     

Methane uptake and nitrous oxide emission in Japanese forest soils and their relationship to soil and vegetation types

Abstract

To determine the means and variations in CH₄ uptake and N₂O emission in the dominant soil and vegetation types to enable estimation of annual gases fluxes in the forest land of Japan, we measured monthly fluxes of both gases using a closed-chamber technique at 26 sites throughout Japan over 2 years. No clear seasonal changes in CH₄ uptake rates were observed at most sites. N₂O emission was mostly low throughout the year, but was higher in summer at most sites. The annual mean rates of CH₄ uptake and N₂O emission (all sites combined) were 66 (2.9–175) µg CH₄-C m^?2 h^?1 and 1.88 (0.17–12.5) µg N₂O-N m^?2 h^?1, respectively. Annual changes in these fluxes over the 2 years were small. Significant differences in CH₄ uptake were found among soil types (P < 0.05). The mean CH₄ uptake rates (µg CH₄-C m^?2 h^?1) were as follows: Black soil (95 ± 39, mean ± standard deviation [SD]) > Brown forest soil (60 ± 27) ≥ other soils (20 ± 24). N₂O emission rates differed significantly among vegetation types (P < 0.05). The mean N₂O emission rates (µg N₂O-N m^?2 h^?1) were as follows: Japanese cedar (4.0 ± 2.3) ≥ Japanese cypress (2.6 ± 3.4) > hardwoods (0.8 ± 2.2) = other conifers (0.7 ± 1.4). The CH₄ uptake rates in Japanese temperate forests were relatively higher than those in Europe and the USA (11–43 µg CH₄-C m^?2 h^?1), and the N₂O emission rates in Japan were lower than those reported for temperate forests (0.23–252 µg N₂O-N m^?2 h^?1). Using land area data of vegetation cover and soil distribution, the amount of annual CH₄ uptake and N₂O emission in the Japanese forest land was estimated to be 124 Gg CH₄-C year^?1 with 39% uncertainty and 3.3 Gg N₂O-N year^?1 with 76% uncertainty, respectively.     

Formation of clay minerals in soils developed from basic volcanic rocks under semiarid climatic conditions in Lanzarote,Spain

Clay formation in soils was studied in four landscapes of different ages in Lanzarote (Canary Islands). Landscape IV_B is about 250 years old, IV_A subrecent, III early young pleistocene, and landscape I, late tertiary. The soils have developed from basic to ultrabasic pyroclastic fall deposits or basalt.Clay formation in soils of landscape IV_B is in an initial stage having a clay content of 1–2 kg/m², whereas in landscape IV_A 30–40 kg/m² and in landscape III 100–200 kg clay/m² are accumulated. In polygenetic soils of landscape I more than 3000 kg clay/m² can be found. In the youngest soils IV_B, smectite is the most prominent clay mineral, whereas IV_A-soils are dominated by “amorphous” clay. The clay fraction in older soils contains illite, smectite as well as kaolinite in smaller quantities.The chemical composition of the clay fraction of soils with different ages changes significantly according to the mineral composition.     

Inheritance of the branching in hybrid populations among tetraploid wheat species and the new branched spike line 166-Schakheli

The new branched spike form of wheat was synthesized from a cross between a complex wheat line 171ACS {[(T. durum Desf. × Ae. tauschii Coss.) × S. cereale L. ssp. segetale Zhuk.] × T. aestivum L. ‘Chinese Spring’} (2n = 6x = 42, AABBDD) and durum wheat variety T. durum Desf. ‘Bereketli-95’ (2n = 4x = 28, AABB). This branched spike form is distinguished significantly from the other branched spike forms known so far. Later on basis of these plants have been developed the branched spike lines. This study was aimed to generate the segregating populations from reciprocal (F₁–F₃) and backcross (BC₁F₁–BC₁F₃) crosses between one of such lines—166-Schakheli (2n = 4x = 28, AABB) and tetraploid wheat species (T. polonicum L., T. turanicum Jakubz., T. durum Desf.) for revealing the inheritance character of this branching trait and study meiotic behavior in reciprocal (F₁, F₂) and backcross (BC₁F₁) progenies. Results showed that this trait is controlled by a single recessive gene despite certain irregularity against Mendelian law in F2 generations and does not depend on gene dosage, i.e., number of chromosomes.     

Estimation of natural outcrossing rate and genetic diversity in Lima bean (<Emphasis Type="Italic">Phaseolus lunatus</Emphasis> L. var. <Emphasis Type="Italic">lunatus</Emphasis>) from Brazil using SSR markers: implications for conservation and breeding

Lima bean (Phaseolus lunatus L.) is an important food source in Brazil, especially in the northeast region, where its production and consumption are high. The goals of the present study were to estimate natural outcrossing rates and genetic diversity levels of Lima bean from Brazil, using ten microsatellite loci to obtain information for their conservation and breeding. Fourteen accessions were selected from an experiment in field with open-pollinated and with the presence of pollinating insects. Twelve seeds of each of the 14 selected accessions were grown in screenhouse for tissue harvest and DNA extraction. The multilocus model was used to determine the reproductive system. The outcrossing rate was 38.1 % (t_m = 0.381; t_s = 0.078), and the results indicated a mixed mating system with a predominance of selfing (1 ? t_m = 61.9 %). The biparental inbreeding rate was high (t _m  ? t _s  = 0.303) and the multilocus correlated paternity was quite high (r _p(m) = 0.889), indicating that the progeny was mostly composed of full sibs. The average effective number of pollen donors per maternal plant (N _ep ) was low (1.12), and the fixation index for maternal genotypes (F _m ) was 0.945, indicating that most genitors resulted from inbreeding. The studied families presented considerable genetic variability: A = 6.10;  %P = 30; H _e  = 0.60 and H _o  = 0.077. Total diversity was high (H _T = 0.596), and a portion was distributed within families (H _S = 0.058). In addition, diversity was higher between families (D _ST = 0.538), and genetic differentiation was high (G _ST = 0.902). The results presented here can be used in the implementation of Lima bean conservation and breeding programs in Brazil.     

Effects of polymeric slow release fertilizer on Chinese cabbage growth and soil nutrients

One pot experiment was conducted to study the effects of a new polymeric slow release fertilizer (PRF) on Chinese cabbage growth and soil nutrients. The experiment comprised three kinds of fertilizer (common compound fertilizer, 21% and 45% solubility of PRF in 25°C water, all fertilizers with N:P₂O₅:K₂O = 10:5.7:20) and three fertilizer levels (0, 21.6 and 43.2 g m^?2). Results showed that the high water-soluble PRFs (PRFHH and PRFHL) fit nutrient requirements of Chinese cabbage, and the high fertilization level significantly increased yield and improved quality of Chinese cabbage. Although the PRFHL treatment at 21.6 g fertilizer m^?2 had one-half less supplied nutrient than that of common compound fertilizer treatment (43.2 g fertilizer m^?2), the yield of Chinese cabbage with PRFHH and PRFHL was 8.0% more. The soluble sugar, vitamin C and leaf chlorophyll contents of Chinese cabbage can be effectively improved with PRFHH (43.2 g m^?2), PRFHL (21.6 g m^?2) and PRFLH (low water-soluble PRF, 43.2 g m^?2). The PRF treatment reduced the nitrate content and improved soil capacity of supplying nutrient effectively, and there were no changes in values of pH and electrical conductivity of soil.     

Reclamation of a Badarkhali hot spot of acid sulfate soil in relation to rice production by basic slag and aggregate size treatments under modified plain–ridge–ditch techniques

Abstract

A field experiment was conducted for the reclamation of a Badarkhali hot spot of acid sulfate soil manipulated by flash leaching followed by basic slag (BS) at 10 t ha^?1 (BS₁₀) and 20 t ha^?1 (BS₂₀) and aggregate sizes (A) of soil less than 20 mm (A₂₀) and less than 30 mm (A₃₀) treatments under two different techniques (Tech 1: pyrite layer at top, jarosite layer at middle and topsoil at the bottom of the ridge; Tech 2: topsoil at top, pyrite layer at middle and jarosite layer at the bottom of the ridge). Responses to two cultivars of rice (Pizam [local cultivar] and BR 14 [high yielding cultivar]) with the treatments were evaluated. The initial soil had a very low pH(H₂O) 4.0 and a high electrical conductivity (EC) of 1.4 m S^?1, and the pyrite content was 68 g kg^?1. The exchangeable Mg content of the soil was approximately twice that of Ca and the Al content was at a highly toxic level. The average soil data of all the treatments, except for the control plots (where no amendment was applied), after harvesting of rice increased by 1.1 units for soil pH and 17–524% for the contents of N, P, Ca and Mg, while the concentrations of Fe, Al, Na, Cl^? and SO₄ ^2– decreased by 30–94% compared with the initial soil. The maximum growth and yield of rice grains (4.4 t ha^?1) were obtained by the Pizam compared with the BR 14 (4.0 t ha^?1) in the A₂₀BS₂₀ treatment in the ridges of Tech 2. The lowest grain yields of 0.02 (BR 14) and 0.07 t ha^?1 (Pizam) were recorded for the control plots. The other treatments also resulted in significantly (P ≤ 0.05) improved performance on rice production. The highest N, P, K, Ca and Mg contents in the shoots of BR 14 and Pizam rice were obtained under the A₂₀BS₂₀ treatment followed by the A₂₀BS₁₀ ≥ A₃₀BS₂₀ treatments. Application of A₂₀BS₂₀ under Tech 2 is the most appropriate reclamation option and the local Pizam is the most suitable rice for this soil.