Over the last years, Brazil has appeared among the new tropical wine producing countries. The joined effect of rising air temperature and decreasing precipitation makes it important to quantify the trend of the thermohydrological conditions of the commercial vineyards. The aims of the current research were to classify and delimit these conditions for the winemaking processes under different time scenarios in the Brazilian Northeastern region. Bioclimatic indicators were used together with long-term weather data and projections of the IPCC emission scenarios under simulated pruning dates. The results showed that decreasing of precipitation should be good for wine production when irrigation water is available, but rising air temperature will affect the wine quality and stability mainly for pruning done from November to March. The best pruning periods are around May for any time scenario considered. In general, more care should be taken for pruning happening in other periods of the year, regarding the effect of increasing thermal conditions on wine quality. The classification and delimitation done, joined with other ecological characteristics, are important for a rational planning of the commercial wine production expansion, mainly in situations of climate and land use changes together with rising water competition.
Field trials were conducted at the Teaching and Research Farm, Faculty of Agriculture, University of Maiduguri, Maiduguri (11°47.840′N; 13°12.021′E; elevation 319 m asl), in Borno State in semiarid zone of Nigeria during the 2010 and 2011 rainy seasons. The objectives of the study were to evaluate the agronomic performances of some improved cowpea varieties and to identify the physiological traits associated with high grain yield in the semiarid zone of Nigeria. The trial consisted of eight treatments, which included two local varieties, namely, Kannanado White and Borno Brown and six improved varieties, namely, IT90K-277-2, IT97K-568-18, IT89KD-288, IT97K-499-35, IT98K-131-2, and IT89KD-391. The treatments were laid out in a randomized complete block design replicated three times. The gross plot size was 5.0 m × 4.0 m (20 m 2 ) while the net plot size was 3.6 m × 3.0 m (10.8 m 2 ). The results showed that the improved varieties, namely, IT90K-277-2, IT97K-499-35, IT98K-131-2, and IT89KD-288, had significantly higher grain yield per hectare and matured earlier to escape drought in this agroecological zone. The local varieties also had significantly heavier grains, took more days to reach first and 50% flowering, and matured later than the improved varieties. Cowpea grain yield per hectare was highly positively correlated with harvest index, shell weight, soil moisture suction measurements, shelling percentage, and grain yield per plant and also significant negative correlation between cowpea grain yield per hectare and number of days to first and 50% flowering, 100-grain weight, number of days to physiological maturity, and pod development period. The results also indicated that fodder yield per hectare was highly positively correlated with photosynthetically active radiation thereby indicating that higher photosynthetically active radiation produced higher yield of fodder.
In north of Tunisia, wild cardoon ( Cynara cardunculus L. var. sylvestris (Lamk) Fiori) is called “khurshef.” It is consumed mainly for its fleshy stems and leafstalks in some traditional dishes. In some regions, heads were used to prepare cheese. North Tunisian germplasm has been currently damaged by severe genetic erosion, pollution, urbanization, and bad farming practices. In order to preserve this species and to assess morphological relationship between accessions, the present study aims to prospect and to characterize individuals in several areas of the north of Tunisia. Six populations were collected and then 20 individuals per population were evaluated using UPOV (International Union for the Protection of New Varieties of Plant) descriptors related to leaves, leafstalks, and heads. Multivariate analyses were used to elucidate relationship among the studied populations. Principal components analysis revealed more diversity within each population. Cluster study reveals large variability among populations. This analysis allows classifying the germplasm of wild cardoon into five groups. Similarities observed between ecotypes despite their distinctiveness of geographic origin suggest a narrow genetic base. These analyses are very useful for the management and the use of wild cardoon in future breeding programs for Cynara germplasm.
A study was conducted to evaluate four common coffee (Coffea arabica) varieties in Zimbabwe for drought tolerance and ability to recover. The plants were subjected to drought stress for 21 and 28 days with evaluation of recovery done 14 days after interruptive irrigation. Coffee varieties were not significantly different in initial fresh and dry biomass before stressing (P>0.05). CR95 had significantly accumulated more (P<0.05)dry root mass (0.8 g) than the rest of the varieties after 21 days of drought stress. SL28 and CR95 had an 8.3% increase in dry biomass while Cat128 did not gain any dry biomass after 21 days of drought stress. CR95 had significantly more (P<0.05) total dry biomass after 21 days and 28 days of drought stress while SL28 was consistently the least in both periods. Cat129 had the highest recovery gains in dry root, dry shoot, and total dry biomass after 21 days and 28 days of drought stress. Initial root biomass was negatively correlated with changes in total fresh and dry biomass of young coffee (r>0.60) after both 21 and 28 days of drought stress, indicating that root biomass may be the most important factor determining drought tolerance in coffee varieties.
Present study was conducted to appraise the inhibitory effects of cadmium applied at different time intervals on various growth and biochemical parameters in two maize lines, Maize-TargetedMutagenesis 1 and 2 (MTM-1 and MTM-2). Twenty-day-old seedlings were exposed to 0, 3, 6, 9, and 12 mg CdCl 2 kg −1 sand. Both maize lines exhibited significant perturbations in important biochemical attributes being employed for screening the crops for cadmium tolerance. The results showed that a higher concentration of cadmium (12 mg CdCl 2 kg −1 ) considerably reduced the plant growth in line MTM-1 on the 5th, 10th, and 15th day after the treatment. In contrast, irrespective of exposure time, the plant biomass and leaf area did not show inhibitory effects of cadmium, specifically at 3 mg CdCl 2 kg −1 in line MTM-2. In addition, MTM-2 was found to be more tolerant than line MTM-1 in terms of lower levels of hydrogen peroxide (H2O2), malondialdehyde (MDA) contents, and relative membrane permeability (RMP). Moreover, H2O2, MDA, RMP, and anthocyanin increased at all levels of cadmium in both lines, but a significant decline was observed in photosynthetic pigments, total free amino acids, and proline contents in all treatments particularly on the 10th and 15th day after treatment.
A study was done to analyse the change in swelling power (SP) and the water soluble index (WSI) of native starches obtained from five different cultivars of sweet potatoes (swp 1 (Wariyapola red), swp 3 (Wariyapola white), swp 4 (Pallepola variety), swp 5 (Malaysian variety), and swp 7 (CARI 273)) commonly consumed in Sri Lanka. Extracted starch from fresh roots, two to three days after harvesting has been modified using 20%, 25%, and 30% moisture levels and heated at 85°C and 120°C for 6 hours and determined the SP and WSI. Results were subjected to general linear model, and analysis of variance (ANOVA) was carried out by using MINITAB version 14. Overall results showed a significantly high level () of SP and WSI in all the cultivars of moisture—temperature treated starches than their native starch. Correlation analysis showed an effect on SP with the variation in the cultivar, temperature, and moisture; temperature combination and moisture alone had no significant effect. Significantly high levels of swelling power () were observed in 20%—85°C, and 30%—120°C and the highest amount of swelling in the modified starch than its native form was observed in swp 7 cultivar. Results revealed a nonlinear relationship in the WSI with the cultivar type, moisture level, and the lower moisture—temperature combinations but higher temperature—moisture combinations had a significant effect. SP and WSI had a slight positive linear relationship according to analysis. Based on the results, a significantly high level of swelling and water solubility of native starches of different cultivars of sweet potatoes can be achieved by changing the moisture content to 30% and heating at 120°C for 6 hours.
This experiment investigated the relationship between tobacco canopy spectral characteristics and tobacco biomass. A completely randomized design, with plantings on the 15th of September, October, November, and December, each with 9 variety × fertiliser management treatments, was used. Starting from 6 weeks after planting, reflectance measurements were taken from one row, using a multispectral radiometer. Individual plants from the other 3 rows were also measured, and the above ground whole plants were harvested and dried for reflectance/dry mass regression analysis. The central row was harvested, cured, and weighed. Both the maximum NDVI and mass at untying declined with later planting and so was the mass-NDVI coefficient of determination. The best fitting curves for the yield-NDVI correlations were quadratic. September reflectance values from the October crop reflectance were statistically similar (P>0.05), while those for the November and the December crops were significantly different (P<0.05) from the former two. Mass at untying and NDVI showed a quadratic relationship in all the three tested varieties. The optimum stage for collecting spectral data for tobacco yield estimation was the 8–12 weeks after planting. The results could be useful in accurate monitoring of crop development patterns for yield forecasting purposes.
On-farm beans research was carried out in Kigoma region, Tanzania. Objectives were to evaluate beans varieties for yield under farmers’ management conditions and to assess farmers’ preferences on beans varieties. Nine farmers from three villages with three farmers per village participated in beans trials. A randomized complete block design with five plots per replications was used to evaluate five bean varieties: Lyamungo 90, Jesca, Uyole 94, Kablanketi, and Kigoma yellow (control). Beans were planted on a 10 m × 2.5 m plot at a spacing of 50 cm × 20 cm. Data was subjected to analysis using ANOVA table in GenStat statistical computer software. Three villages × three seasons resulted in nine environments which were used for stability analysis. Farmers developed their criterion to assess the performance and acceptability of beans varieties. Lyamungo 90 and Jesca ranked high and outyielded other varieties with an average yield of 1430.00 and 1325.67 kg ha−1, respectively. Genotypes sum of squares accounted for the most of the variability (89.12%). Introduction of high yielding bean varieties with the desired farmers’ traits is expected to revamp beans production and contribute to the improved food security in Tanzania.
Crop management decisions such as sowing density, row distance and orientation, choice of cultivar, and weed control define the architecture of the canopy, which in turn affects the light environment experienced by crop plants. Phytochromes, cryptochromes, phototropins, and the UV-B photoreceptor UVR8 are sensory photoreceptors able to perceive specific light signals that provide information about the dynamic status of canopy architecture. These signals include the low irradiance (indicating that not all the effects of irradiance occur via photosynthesis) and low red/far-red ratio typical of dense stands. The simulation of selected signals of canopy shade light and/or the analysis of photoreceptor mutants have revealed that canopy light signals exert significant influence on plant performance. The main effects of the photoreceptors include the control of (a) the number and position of the leaves and their consequent capacity to intercept light, via changes in stem height, leaf orientation, and branching; (b) the photosynthetic capacity of green tissues, via stomatic and nonstomatic actions; (c) the investment of captured resources into harvestable organs; and (d) the plant defences against herbivores and pathogens. Several of the effects of canopy shade-light signals appear to be negative for yield and pose the question of whether breeding and selection have optimised the magnitude of these responses in crops.
Response of six improved grass pea genotypes to prolonged salinity stress was investigated on seedlings grown in pot experiment using 150 mM NaCl up to 60 days of growth after commencement of treatment (DAC). NaCl exposure significantly reduced growth potential of varieties PUSA-90-2 and WBK-CB-14, but no such effect was observed in varieties B1, BioL-212 and in two mutant lines LR3 and LR4. A time-bound measurement at 15, 30 and 60 DAC revealed significant reduction in plant dry matter production, orchestrated through abnormally low capacity of leaf photosynthesis accompanied by low K + /Na + ratio and onset of oxidative stress in all six genotypes at 15 DAC and the extension of the phenomena in PUSA-90-2 and WBK-CB-14 to 60 DAC. High superoxide dismutase (SOD) activity coupled with low ascorbate redox and declining ascorbate peroxidase (APX) and catalases (CAT) levels led to abnormal rise in H 2 O 2 content at reproductive stage (30 DAC) in the latter two genotypes, consequently, resulting in NaCl-induced oxidative damage. H 2 O 2 level in the rest of the four genotypes was modulated in a controlled way by balanced action of SOD, APX and CAT, preventing oxidative damage even under prolonged NaCl-exposure. Enzyme isoforms were involved in regulation of foliar H 2 O 2 -metabolism, which was critical in determining As tolerance of grass pea genotypes.
Screening of available local halophytes for salinity tolerance is of considerable economic value for the utilization of heavy salt-affected lands in coastal tidal-flat areas and other saline areas. In this study, the germination and seedling pot experiments on salt tolerance of eight halophytic species from Yellow River Delta, China, at seven NaCl concentrations (0, 50, 100, 150, 200, 250, and 300 mM), were conducted at both growth stages. Results showed that germination rate and germination index decreased with an increase in NaCl concentration. The higher germination rates were obtained from Tamarix chinensis and Suaeda salsa seeds exposed to 0~200 mM NaCl. At the seedling stage, the salt tolerances of eight halophytes were also different from each other. Tamarix chinensis had significantly greater fresh biomass and plant height in relative terms than the others in all salt treatments. The order of the relative growth yield in seedling was Tamarix chinensis > Suaeda salsa > Salicornia europaea > Limonium bicolor > Atriplex isatidea > Apocynum venetum > Phragmites australis > Sesbania cannabina. The comprehensive analysis showed that Tamarix chinensis had the highest tolerance to salt, followed by Suaeda salsa, and the salt tolerance of Sesbania cannabina was the lowest.
The evaluation of pollen viability and its germination capacity are two essential criteria for pollinator’s characterization. This study was carried out to evaluate pollen quality of eight caprifigs grown in the center-east and north-west of Tunisia. Two colorimetric tests 2,3,5-triphenyl tetrazolium chloride (TTC) and acetocarmine were used to estimate pollen viability. Germination rate and pollen tube growth in a culture medium containing 5% sucrose, 5 ppm boric acid (H 3 BO 3 ) and 1% agar were registered after 24, 48, and 72 hours (H) of incubation. Results showed that the highest pollen viability rate (84%) was obtained by TTC test in caprifig Assafri, followed by Jrani (80.2%), Djebba 2 (77.8%), and Djebba 1 (73.6%). That of other caprifigs did not exceed 50% for the two tests. In all caprifig types, germination rate and pollen tube growth varied according to the incubation period. The highest percentage of germination (72%) and maximum pollen tube length (960 μ m) were recorded after 72 H of incubation in caprifigs Assafri and Jrani, respectively. Among the caprifigs studied, four types (Assafri, Jrani, Djebba 1, and Djebba 2) appeared to be suitable pollinators with respect to the criteria investigated.
Tricholoma matsutake and Rhizopogon roseolus form ectomycorrhizal (ECM) association with their host plant on natural habitats. The main objective of this study was to test mycelial growth, morphology, and host plant survival both in vitro and in vivo when treated with enriched media. Aseptically germinated seedlings of Pinus densiflora and P. thunbergii were inoculated with the strains of T. matsutake and R. roseolus , respectively. Under in vitro conditions mycelial growth rates performed best on pH 5 and were better on Modified-Melin-Norkrans-(MMN) based medium and Potato Dextrose Agar (PDA); addition of micronutrients and vitamins in MMN mycelial growth rates had 6–27% differences. Without ECM, plant survival rates on standard media were 30% to below 30% and by inclusion of elements they were 50% to 80%. On in vivo , soil containing different media with ECM allowed successful mycorrhizal association and increased seedling survival rates approximately 100%. Our findings confirm that MMN and PDA allowed higher mycelial growth but poor plant survival (<30%); however, enriched media supported 100% plant survival with successful ECM associations. The present method is advantageous in terms of giving objectivity for ECM by employing suitable media for strains and host plant, and making it possible for mass production of ECM-infected seedlings.
The effect of carboxymethyl cellulose and alginate coating combined with brewer yeast on postharvest grape preservation was investigated. The postharvest grapes were coated with 2% of alginate and 3% of carboxymethyl cellulose combined with1.5×109 CFU/mL of brewer yeast. The combined treatment samples showed good sensory character on day 13 compared with control samples or only coated samples. The increase of weight loss and decrease of total soluble solids of combined treatment grapes were restrained. Furthermore, the protective enzymes including superoxide dismutase, peroxidase, and catalase of combined treatment sample showed higher activities. Accordingly, the increase of malonaldehyde content was also restrained and more vitamin C was preserved in combined treatment samples. At day 13, the weight loss rate and the total soluble solids of grape treated with coating + yeast were 23.6% lower and 20.6% higher than those of control samples, respectively. Coating grapes with 2% of alginate and 3% of carboxymethyl cellulose combined with brewer yeast of1.5×109 CFU/mL was a well-proven method to preserve postharvest grapes.
Knowledge of the physical properties of date fruit is necessary for the design of postharvesting equipment such as cleaning, sorting, grading, kernel removing, and packing. Also, the physical and mechanical properties are incorporated in the development of the grading machine as a case study. In this study, some physical and mechanical properties of three mandarin cultivars, as promising fruits, were analyzed to help the design of handling machines. According to results, the greatest dimensional characteristics were found for Page cultivar, whereas Onsho cultivar showed the lowest sphericity value (93%), and the highest sphericity was observed in Clementine cultivar (97%). The specific gravity of Page cultivar was 0/97, and this cultivar had the biggest fruit. Thus, it may be used for export. The volume measured was 1% higher than the calculated assumed shape of the spheroid . The relationship between diameters and mass was linear, and the correlation was high for all studied cultivars and mixed cultivar (combined all data). There was a linear relation between mass and volume of the mixed cultivar of mandarin with a high coefficient of determination.
Tobacco crop area and yield forecasts are important in stabilizing tobacco prices at the auction floors. Tobacco yield estimation in Zimbabwe is currently based on statistical surveys and ground-based field reports. These methods are costly, time consuming, and are prone to large errors. Remote sensing can provide timely information on crop spectral characteristics which can be used to estimate crop yields. Remote sensing application on agriculture in Zimbabwe is still very limited. Research should focus on identifying suitable reflectance indices that are related to tobacco growth and yield. Varietal yield response to fertiliser and planting dates as well as suitable temporal windows for spectral data collection should be identified. The challenges of the different tobacco land sizes have to be overcome by identifying suitable satellite platform, with sufficient spectral resolution to separate the tobacco crop from the adjacent competing crops and noncrop vegetative surfaces. The identified suitable index should be strongly correlated with tobacco in season dry mass and yield. The suitable vegetative indices can be employed in establishing tobacco cropped area and then apply the long-term area yield relationship from government and nongovernmental statistical departments to estimate yield from remote sensing derived cropped area.
This paper proposes five new imputation methods for unbalanced experiments with genotype by-environment interaction (G×E). The methods use cross-validation by eigenvector, based on an iterative scheme with the singular value decomposition (SVD) of a matrix. To test the methods, we performed a simulation study using three complete matrices of real data, obtained from G×E interaction trials of peas, cotton, and beans, and introducing lack of balance by randomly deleting in turn 10%, 20%, and 40% of the values in each matrix. The quality of the imputations was evaluated with the additive main effects and multiplicative interaction model (AMMI), using the root mean squared predictive difference (RMSPD) between the genotypes and environmental parameters of the original data set and the set completed by imputation. The proposed methodology does not make any distributional or structural assumptions and does not have any restrictions regarding the pattern or mechanism of missing values.
An experiment laid in a Randomized Complete Block Design with 4 blocks and 5 treatments, was done at Kutsaga Research Station in the 2012 / 2013 season to study the impact of time of weeding on tobacco production. The treatments comprised of different times of weed control with a weed free treatment as the control. The variables measured were stalk heights at 5, 6 and 7 weeks after planting and, leaf expansion measurements were also recorded at 9, 10 and 11 weeks. Leaf yield was measured at untying using a digital scale. Results showed that Tobacco stalk heights were affected at 5 W.A.P since significant differences (P<0.05) were noted among the treatments. Suppressive effects of weeds were shown at 6 and 7 W.A.P due to effective competition (RCI > 0) in all other treatments excluding the control. There were significant differences (P<0.05) among the treatments on leaf expansion at 9, 10 and 11 W.A.P. The treatment weeded at 4 W.A.P showed leaf yield that was significantly higher (L.S.S = 270.8) than the treatment weeded at 2 W.A.P. Basing on the 3 reaps recorded, time of weeding had an influence tobacco yield.
Sulfonylureas represent one of the largest herbicide groups that have been widely used since 1980s. Their continuous use has resulted in development of sulfonylurea resistance in weeds. The aim of this research was to investigate options to manage putative sulfonylurea-resistant chickweed in barley stands and to evaluate the effect of chickweed and its management on barley yield. A field experiment was arranged as a randomized complete block design and included 14 herbicide treatments applied at two different times. Tribenuron-methyl (sulfonylurea) affected minimal control of chickweed. A bromoxynil-ioxynil (photosystem II inhibitor) mix did not control chickweed efficiently. However, nearly total control was achieved with fluroxypyr, mecoprop, and their mixtures (synthetic auxins and photosystem II inhibitors). Chickweed had no effect on barley yield whether controlled or uncontrolled. Therefore, further evaluation of the chickweed management threshold would be needed. It seems that even in the boreal region, typified by a cold climate, limited solar radiation, a very short growing season, and relatively low-intensity cropping systems, unilateral use of sulfonylureas might lead to herbicide resistance. Although resistant weed populations can be controlled with herbicides of groups other than the sulfonylureas, this represents an increasing problem when planning weed management, especially when including sulfonylurea-resistant crops.
Phomopsis seed decay (PSD) of soybean is caused primarily by the fungal pathogen Phomopsis longicolla Hobbs along with other Phomopsis and Diaporthe spp. This disease causes poor seed quality and suppresses yield in most soybean-growing countries. Infected soybean seeds can be symptomless, but are typically shriveled, elongated, cracked, and have a chalky white appearance. Development of PSD is sensitive to environmental conditions. Hot and humid environments favor pathogen growth and disease development. Several control strategies have been used to manage PSD and reduce its impact; however, the use of resistant cultivars is the most effective method for controlling PSD. Efforts have been made to identify sources of PSD resistance in the past decades. At least 28 soybean lines were reported to have certain levels of PSD resistance in certain locations. Inheritance of resistance to PSD has been studied in several soybean lines. In this paper, general information about the disease, the causal agent, an overview of research on evaluation and identification of sources of resistance to PSD, and inheritance of resistance to PSD are presented and discussed.
