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Lack of appropriate agronomic practices is one of the major causes for soil erosion and low yields in teff (Eragrostis tef [Zucc.]) production in Ethiopia. A 3-yr study was conducted at the Aba Gerima watershed in northwestern Ethiopia, to investigate the effects of two tillage practices (reduced tillage [RT] and conventional tillage [CT]), two planting methods (row planting [RP] and broadcast planting [BP]), and two compaction options (with [+T] and without [–T] trampling) on soil loss and teff yields in a split-split plot arrangement. Sediment concentration ranged from 0.01 to 5.37 g L⁻¹ (mean, 0.25 g L⁻¹) in our study. Accordingly, the estimated total (August–October) soil loss ranged from 0.2 to 0.5 t ha–¹ (mean, 0.3 t ha–¹). The sediment concentration and total soil loss were significantly influenced (P

Teff is the most strategic cereal crop grown from high rainfall to drought prone areas of Ethiopia, where it covers nearly 30% of the land allotted for cereals. However, its productivity remains very low due to lack of knowledge and research interventions. To investigate the grain yield potential, estimate the genetic parameters, and the diversity, a pot experiment with intensive management and a field experiment with conventional management at two contrasting locations for two seasons using the same 317 genotypes and additional 3 improved cultivars in the field experiment were carried out. The results showed highly significant variation among the genotypes for grain yield, biomass, harvest index, and phenological traits under both experiments. The best linear unbiased predictor (BLUP)-adjusted grain yield performance of the genotypes ranged from 4.2 to 8.8 g/plant in the intensive management and 1.8 to 4.3 g/plant in the field growing condition with conventional management. Coefficient of genetic variation, heritability, and expected genetic advance for grain yield were the highest in both experiments. Among the phenological traits, the grain filling period in the intensive growing condition exceptionally showed the highest genetic coefficient of variation and genetic advance. The high grain yield performance and wider range of the harvest index observed under the intensive management condition with moderate to high heritability signifies the genetic potential of teff for further improvement through trait recombination.

Background: Teff (Eragrostis tef (Zucc.) Trotter) is an important grain crop, but a paucity of research means that the mean yield is below 1.5 t ha−1. Its high genetic diversity has not been exploited to improve its yield potential. Previous efforts at increasing yield were based entirely on phenotypic, morphologic, and agronomic merits. However, photosynthetic capacity has been neglected, so its possible contributions to yield improvements remain unexplored. Results: We grew 15 teff cultivars in a controlled environment to explore variations in photosynthetic capacity and nitrogen use efficiency (NUE), and examined the relationships of gas exchange and NUE before anthesis with growth and yield attributes. Substantial differences were found in leaf photosynthetic rate (19 ± 9 μmol m−2 s−1, mean ± SD), stomatal conductance (0.11 ± 0.09 mol m−2 s−1), and transpiration rate (2.4 ± 1.3 mmol m−2 s−1). The cultivars differed significantly (P < 0.05) in both NUE (190 ± 227 g m−2) and photosynthetic NUE (59 ± 34 µmol g−1s−1). On average, the plants partitioned 29% of N to leaf, 28% to panicle, and 13% to stem before anthesis. Yield and biomass production were closely associated with photosynthetic capacity and NUE. Clustering of the cultivars on the basis of photosynthesis, NUE, growth, and yield indicates wide variations in photosynthetic capacity and NUE in the wider teff gene pool that should be exploited. Conclusion: We conclude that leaf photosynthesis and NUE are positively related to yield and biomass production in teff.

Herbs of the Labiatae have relatively low salt tolerance. They are widely grown in drylands, but salt stress there is a typical problem and may reduce yields. To examine their salt tolerance mechan...

Despite teff being the major food crop cultivated in Ethiopia, its productivity remained very low (

Prosopis juliflora is a useful “multi-purpose” tree, but it invades rapidly in arid and semi-arid environments, causing livelihood degradation of local communities. A rain pulse under drought conditions has been reported to be an important factor to promote plant invasion. The purpose of this research was to evaluate the effect of a rain pulse on the invading process of Prosopis juliflora and to propose a feasible plan to control the expansion of this species in Sudan. First, seed germination was examined under eight irrigation conditions, corresponding to 4–32 mm of rainfall. Most seeds imbibed in all the irrigation conditions, about half or more of the imbibed seeds germinated in 12 mm or more of irrigation. Twenty mm or more of irrigation induced seed emergence. Second, initial growth of germinated seeds was examined under ten irrigation conditions (1–32 mm rainfall) over 54 hours or 138 hours of cultivation. Radicle elongated most vigorously in 24 mm irrigation, and extended over 20 cm in length. Allo...

Invasive alien plants such as mesquite (Prosopis juliflora) alter patterns of groundwater uptake. We measured the groundwater level beneath a mesquite stand in an arid area in Sudan. The changes in groundwater level closely followed plant water uptake. The groundwater level started to decline a few hours before sunrise, recovered around noon, and then continued to decline until a few hours after sunset, before recovering again during the night. Thus, groundwater level showed two peaks: just before sunrise and around midday. The midday recovery was due to the depression of photosynthesis by heat and light.

Seeds of Panicum miliaceum, P. sumatrense, Setaria glauca and S. italica were raised in polyvinylchloride (PVC) tubes filled with sandy soil in a greenhouse to determine the effect of preand post-heading water deficit on growth and grain yield. Water stress treatment was initiated 25 days after sowing. The grain yield of S. italica and S. glauca decreased 80 and 70%, respectively, under water stress; and that of P. miliaceum and P. sumatrense decreased 36 and 20%, respectively. The reductions were ascribed to smaller number of grains per panicle, smaller number of panicles and lighter total dry weight. The grain yield decreased when water stress was imposed before heading in S. italica and S. glauca ,but both before and after heading in P. miliaceum and P. sumatrense. Mild water stress decreased the leaf water potential of all millets. Osmotic adjustment of the leaf could not explain the interspecific difference in drought tolerance. Water stress increased the root growth of S. italica ,S. glauca and P. sumatrense at deeper soil layers at heading. At harvest, it also increased root growth at deeper soil layers in S.italica and S. glauca. There was a significant correlation between grain yield and root dry weight among the millets except S. italica. The drought tolerant millet showed greater drought tolerance to water deficit not only at the vegetative stages but also at the reproductive stages than two susceptible millets.

Reaumuria songarica (Pall.) Maxim and Nitraria tangutorum Bobr. are two species growing on nebkhas in dune system. But N. tangutorum distributes more widely than R. songarica does. Sand burial and drought are two major disturbing factors in the field. Experiments were conducted under controlled conditions to investigate sand burial depth and simulated precipitation amount on seed germination, seedling emergence and seedling mass of the two shrubs to explain the dominance of N. tangutorum over R. songarica. Seeds were buried at 6 depths (0, 0.5, 1.5, 3, 5, 8 cm) and irrigated with 3 water regimes (5, 7, 10 mm) in plastic pots (8 cm in diameter and 11 cm in height) under the same light intensity and alternating temperature in an environment controlled growth chamber. R. songarica has a greater germination percentage than N. tangutorum under each burial depth with any water regime. R songarica seed germination increased with burial depth at each water regime and when depth is deeper than 1.5 cm all the seeds germinated under 7 and 10 mm water treatment. N. tangutorum seed germination increased until an optimal burial depth and then decreased. The optimal burial depth shifts with water regime. Seedling emergence of R songarica did not occur at depth deeper than 1.5 cm under any water regime. N. tangutorum seedling emergence maximized at 3, 1.5 and 0.5 cm with 5, 7 and 10 mm water supply regime respectively. Under all the treatments, N. tangutorum seedlings had larger dry mass than R. songarica seedlings. Higher N. tangutorum seedling emergence percentage and seedling mass with given water supply enhance its possibility to appear on nebkhas in the study area.

To analyze how silicon (Si) fertilizer improves plant growth under water stress, we investigated the growth and root responses of sorghum seedlings to Si application. Seedlings were grown hydroponically at two Si levels (0 and 1.78 mM) and under two water stress conditions simulated with polyethylene glycol. The reduction in dry weight due to stress was alleviated by Si application, accompanied by an increase in root water uptake. Silicon application decreased the osmotic potential of the roots without affecting their water content, showing that osmotic adjustment occurred to increase water uptake. An assessment of root solutes suggested that soluble sugar and amino acids (alanine and glutamic acid) were osmolytes responsible for this adjustment. Root anatomical traits related to water transport were not affected by the Si application. These results improved our understanding of the physiological mechanisms that underlie the Si-induced increases in sorghum growth and water uptake under water stress.

It has been reported that elevated CO2 can enhance plant growth and water use, and that desert plants in particular will show the strongest response to rising atmospheric CO2 due to the strong water stress on these plants. In this study experiments were conducted to understand the responses of seedlings from four species, which are dominant in different successional stages in the semi-arid sandy grassland of central Inner Mongolia, to rising temperature and elevated CO2. Seedlings of the four species were grown for 8 weeks at two air temperatures and two CO2 concentration regimes in growth chambers. It was found that for the two Artemisia species and Hedysarum laeve elevated CO2 level resulted in increased relative growth rates (RGR) (6–12%), height increments (24–106%), net assimilation rates (20–45%) and water use efficiencies (WUE) (43–105%), and decreased transpiration (16–55%). For Caragana korshinskii, the elevated CO2 significantly increased the ratio of below ground to above ground biomass (16–23%), height increment (31–65%) and WUE (79–84%). At elevated CO2 level and the higher temperature, the two Artemisia species showed decreased RGR and height increments, while for, C. korshinskii and H. laeve increased RGR and height increments were observed. For A. sphaerocephala the higher temperature also resulted in increased WUE, but decreased WUE for the other three species. Obvious differences were observed between the two Artemisia species and C. korshinskii, with the Artemisia species characterized by higher RGR, lower ratio of below ground to above ground biomass and lower WUE. These findings should be applicable to similar shrub species located in other arid and semi-arid environments.

The increase in UV-B radiation reaching the earth's surface has prompted extensive studies on the effects of UV-B on plants. However, most of these studies have not addressed the close characteristics related to future survival of plant populations. The purpose of this study was to investigate the effects of UV-B radiation on reactive oxygen species (ROS) accumulation and antioxidant defense system in relation to germination, tube length and viability of maize pollen. Our results indicate that increased UV-B radiation decreased the pollen germination rate and tube length in vitro and also its fertilization ability in the field. Production of O(2)(*-) and H(2)O(2) increased by UV-B radiation treatment, and their continuous accumulation resulted in lipid peroxidization. The activities of superoxide dismutase, catalase, peroxidase and DPPH-radical scavenging were decreased by increased UV-B radiation. The increased ROS and lipid peroxidization, and decreased activities of the antioxidants may be attributed to the effects of UV-B radiation on pollen germination, tube growth and fertilization ability.

Aluminum (Al) inhibits plant growth partly by causing oxidative damage that is promoted by reactive oxygen species and can be prevented by improving antioxidant capacity. Ascorbic acid (AsA), the most abundant antioxidant in plants, is regenerated by the action of monodehydroascorbate reductase (MDAR) and dehydroascorbate reductase (DHAR). We investigated the role of MDAR and DHAR in AsA regeneration during Al stress using transgenic tobacco (Nicotiana tabacum) plants overexpressing Arabidopsis cytosolic MDAR (MDAR-OX) or DHAR (DHAR-OX). DHAR-OX plants showed better root growth than wild-type (SR-1) plants after exposure to Al for 2 weeks, but MDAR-OX plants did not. There was no difference in Al distribution and accumulation in the root tips among SR-1, DHAR-OX, and MDAR-OX plants after Al treatment for 24 h. However, DHAR-OX plants showed lower hydrogen peroxide content, less lipid peroxidation and lower level of oxidative DNA damage than SR-1 plants, whereas MDAR-OX plants showed the same extent of damage as SR-1 plants. Compared with SR-1 plants, DHAR-OX plants consistently maintained a higher AsA level both with and without Al exposure, while MDAR-OX plants maintained a higher AsA level only without Al exposure. Also, DHAR-OX plants maintained higher APX activity under Al stress. The higher AsA level and APX activity in DHAR-OX plants contributed to their higher antioxidant capacity and higher tolerance to Al stress. These findings show that the overexpression of DHAR, but not of MDAR, confers Al tolerance, and that maintenance of a high AsA level is important to Al tolerance.

SUMMARYIn non-traditional, heat-stressed environments, wheat breeding programmes were mainly concerned with the introduction and adaptation of high-yielding, heat-tolerant cultivars regardless of the end-use quality. For the recently developed quality-oriented markets, new cultivars should combine the above-mentioned traits with good grain quality to improve economic feasibility of wheat production in these environments. This study aimed to examine the suitability of the conventional sodium dodecyl sulfate sedimentation (SDSS) test for predicting bread-making quality and to evaluate the effectiveness of a prolonged-swelling SDSS test in improving the predictability of end-use quality under heat stress conditions. Conventional and prolonged-swelling SDSS volumes were measured from whole meal of 15 bread wheat genotypes grown for two seasons under two sowing conditions at Gezira Research Farm, Wad Medani, Sudan. Results of correlations of SDSS volumes with total and insoluble protein contents, mixograph peak height and mixograph descending slope indicated the suitability of the SDSS test in predicting bread-making quality under heat-stress irrigated conditions. However, the absence of significant correlations with some quality attributes, such as mixograph peak time and mixograph curve width, demonstrated the non-exclusiveness of the SDSS test for predicting all bread-making quality attributes. The prolonged-swelling SDSS tests did not improve identification of differences among genotypes over the conventional test despite similarly predicting some quality attributes and showing relatively small increases in the correlation coefficient magnitudes with others. SDSS after 10 min from settlement (SDSS10) showed strong correlations with all other SDSS volumes at various times and with most of quality attributes. This suggested that SDSS10 could be used for evaluation of bread-making quality in early generations of the breeding programme in the hot irrigated conditions of Sudan and similar environments.

Sorghum [Sorghum bicolor (L.) Moench] was grown hydroponically with or without 50 ppm silicon (Si), and exposed to water stress from 10 days after sowing (DAS). At 15 and 23 DAS, we measured dry weight and diurnal variations in photosynthetic rate (P N), stomatal conductance (g s), transpiration rate (T), leaf water potential (ψ L), and water uptake rate (23 DAS only). The reduction in dry weight at 23 DAS caused by water stress was ameliorated by silicon. Under water stress, silicon-treated seedlings showed higher g s, P N, and T than untreated ones. ψ L remained almost constant within treatments throughout the daytime. Water uptake rate was reduced by water stress, but the reduction was ameliorated by silicon. We conclude that silicon enhanced water uptake and g s, improving water supply to the leaves. These effects of silicon occurred soon after exposure to water stress.

Field water stress is a common problem in crop production, especially in arid and semi-arid zones and it is widely hypothesized that silicon (Si) could reduce water stress in plants. We set up a greenhouse study to evaluate some silicon sources—potassium silicate (K2SiO3), calcium silicate (CaSiO3) and silica gel for growth and nutrient uptake by four grass species under adequate and deficit irrigation. The four species studied were Rhodes grass (Chloris gayana), Timothy grass (Phleum pratense), Sudan grass (Sorghum sudanense) and Tall fescue (Festuca arundinacea). For all species, the biomass yield response to applied silicon under deficit irrigation was significantly better than under adequate irrigation. The yield response of Rhodes grass across silicon sources was 205% under deficit irrigation compared with only 59% under adequate irrigation; for Sudan grass it was 49% compared with 26% and for Timothy, it was 48% compared with a mere 1%. The higher responses under deficit irrigation suggest ...

Effects of silicon application on stomatal conductance in sorghum were investigated. Sorghum seedlings were grown in culture solution containing 0 or 1.67 mM silicon. On ninth day after giving silicon treatment, when there were no differences in shoot and root growth between the silicon-supplied and silicon-deficient treatments, seedlings were exposed to gradually increasing light intensity, combination of sudden increase and decrease in light intensity, and water stress induced by mixing sorbitol with the culture solution. There was increased stomatal conductance with increasing light intensity and no significant difference was observed between the two silicon treatments. Under water stress, the stomatal conductance of silicon-supplied seedlings was higher than that of silicon-deficient seedlings. The higher stomatal conductance in silicon-supplied seedlings under water stress was attributed to increased leaf water potential due to silicon-induced enhancement of hydraulic conductance. The results indicated that silicon application could affect stomatal conductance in sorghum seedlings through the modification of plant water relations.

To better understand the molecular mechanisms related to growth promotion in the early developmental stages of Eustoma grandiflorum (Raf.) Shinn. under end-of-day far-red light (EOD-FR) treatment, we analyzed the leaf transcriptome of treated (EOD) and untreated plants (Cont) by using RNA-seq technology. EOD-FR treatment for only about 2 weeks in regions with limited sunshine during winter resulted in significantly higher internode length between the 3rd and 4th nodes on the main stem in EOD than in Cont. Among the differentially expressed genes (DEGs) related to synthesis or transport of auxin, higher levels of YUCCA (CL6581) and PIN4 (CL6181) were noted after treatment in EOD than in Cont in the leaf. In addition, high expression levels of GA20ox (Unigene11862) related to gibberellin (GA) synthesis and transcription factor bHLH 135 (CL7761) were observed in the stem of EOD, 3 h after treatment. A vertical section of the stem showed that the pith length of cells at the 4th node was longer in EOD than in Cont. Collectively, these results suggested that EOD-FR treatment increased the expression of DEGs related to GA and auxin biosynthesis, bHLH transcription factor and internodal cell elongation along the longitudinal axis of Eustoma plants.

The effects of five rates [0 (control), 1, 2, 4 and 6 Mg ha−1] of calcium silicate on the growth and water consumption by rhodes grass (Chloris gayana Kunth) and sudan grass (Sorghum sudanense Piper) under wet and dry soil water regimes (60 g and 30 g H2O kg−1 soil respectively) were evaluated in a pot experiment. The effect of the application of silicate on plant biomass was similar to that of the control. However, the shoot and root dry mass varied significantly (P

The difference in rooting pattern between two grain sorghum cultivars differing in drought tolerance was investigated under drought stress. The cultivars, Gadambalia (drought-tolerant) and Tabat (drought-susceptible), were grown in bottomless wooden or acrylic root boxes to examine root parameters. Gadambalia consistently exhibited higher dry matter production and leaf water potential than Tabat under drought stress in both root boxes. In the experiment with wooden root boxes, under a drought condition, Gadambalia extracted more water from deep soil layers (1.1-1.5 m), which was estimated from the reduction in soil water content, than Tabat. This was because Gadambalia had a significantly higher root length density in these soil layers. The high root length density was due to enhanced lateral root development in Gadambalia. In the other experiment with acrylic root boxes, though total root length in the upper soil layer (0-0.5 m) was declined by limited irrigation in both cultivars, the reduction in Gadambalia was moderate compared with that in Tabat owing to the maintenance of fine root growth. Unlike Tabat, Gadambalia had an ability to produce the nodal roots from higher internodes even under drought, which resulted in the high nodal root length of Gadambalia. The growth angle of nodal roots was significantly correlated with root diameter, and the nodal roots from the higher internodes had large diameters and penetrated into the soil more vertically. These results indicate that the responses of roots (i.e. branching and/or growth of lateral root, and nodal root emergence from higher internodes) to soil dryness could be associated with the drought tolerance of Gadambalia.