International Crops Research Institute for the Semi-Arid Tropics
ICRISAT Open Access RepositoryNot a member yet
12134 research outputs found
Sort by
Nucleotide diversity and molecular characterization of soluble starch synthase I gene in wheat and its ancestral species
No full textStarch, the primary determinant of wheat grain yield, contributes 65–75% grain dry weight and 80% of the endosperm dry weight. The starch biosynthetic pathway is regulated by several enzymes, of which the soluble starch synthase (SS) is the most crucial enzyme and is sensitive to environmental change. In the present study, we targeted identifying the unique haplotypes of SSI gene in 17 different wild and cultivated genotypes of wheat, selected for abiotic stress tolerance. Four unique SNPs corresponding to non-synonymous substitution were identified from wild progenitor species, Aegilops tauschii (accessions pau14102 and pau3747), Ae. speltoides (pau15081) and T. dicoccoides (pau7107), each present in exon-1. However, two unique SNPs corresponding to non-synonymous substitution were identified from cultivated wheats, Impala and C591, present in exon-2 and exon-4, respectively. These SNPs correspond to the N-terminal half of the GT5 domain in exon 1–6 and are expected as novel haplotypes contributing to better grain filling and starch deposition under changing environmental conditions. The positive effects of these haplotypes need further validation through molecular and phenotypic evaluation
A Nutritional Survey of Local Barley Populations Based on the Mineral Bioavailability, Fatty Acid Profile, and Geographic Distribution of Fusarium Species and the Mycotoxin Zearalenone (ZEN)
Get PDFKnowledge about the extent of nutrient variability in local barley germplasm is an important prerequisite for efficient crop improvement. The present study is one of the first to assess the potential of Tunisian barley populations (named Testour, Gergis, and Enfidha) as sources of desirable traits for barley improvement and for the prevalence of Fusarium species and the mytoxin zearalenone (ZEN). Analysis of variance revealed highly significant differences between barley populations for nutrients density. The lowest phytate/zinc molar ratios were observed in Testour and Enfidha populations with 7.23 and 9.97, respectively. However, the bioavailability of iron of most barley populations (95.4%) was inhibited mainly by the high phytate content. Oleic acid (15.2–18.7%), linoleic acid (13.8–16.01%), and palmitoleic acid (4.7–14.2%) were identified as predominant fatty acid constituents in all three barley populations. Based on morphologic and molecular characterization, Fusarium graminearum and Fusarium culmorum were the predominant species that infected Testour, Gergis, and Enfidha populations. The concentration of zearalenone ranged between 0 and 140 µg kg−1. The highest levels of zearalenone, 92 μg kg−1 and 60 μg kg−1, were detected in Testour populations that were infected with F. graminearum and F. culmorum, respectively. These relatively low amounts of zearalenone in barley populations can be attributed to the Tunisian climate and the resistance of local genotypes. Testour and Enfidha barley populations could potentially be used to improve breeding programs for biofortification
Effect of Combined Application of Non–Nano and Nano Fertilizers on the Growth, Yield and Oil Content of Sunflower under Semi-arid Conditions
Get PDFField experiment was conducted at International Crops Research Institute for the Semi-Arid Tropics, Hyderabad during early summer season in 2021 and 2022 to study the “Effect of integrated use of Nano and Non–Nano fertilizers on the growth and yield of sunflower under semi-arid conditions”. The experiment was carried out using randomized block design with 3 replications and comprised of 12 treatments. The averages of all study indicators were compared according to L.S.D test at a probability level of 0.05. Results revealed that application of conventional fertilizers as per recommended dose (75:90:30 kg/ha) along with foliar application of nano (19:19:19) N P K at 0.2% at 30 DAS and 60 DAS + nano boron at 0.2 % at ray floret opening stage (T7) recorded highest plant height (195,197 and196 cm), number of leaves (27.43, 28.12 and 27.78), leaf area (7632, 7665 and 7649 cm2 plant-1), leaf area index (LAI) (4.24 4.25 and 4.25), and dry matter production (98.96, 97.64 and 98.30 g/plant) at 90 DAS in both the years and on mean basis. However, treatment T7 was statistically on par with the treatment T9 - Conventional fertilizers 50% as per recommended dose + nano (19:19:19) N P K at 0.2% as foliar spray at 30 DAS and 60 DAS and nano boron at ray floret opening stage. Seed yield (1961,1915 and 1938 kg/ha), stalk yield (4193, 3918 and 4055 kg/ha) were also significantly influenced during both the years respectively with the treatment (T7) was statistically on par with the treatment T9. Lowest seed yield (758, 710 and 734 kg/ ha) and stalk yield (1684, 1702 and 1693 kg/ ha) and oil content (40.73 %, 39.67% & 40.20) was recorded with the control in both the years and on mean basis
Variability in soybean yields, nutrient use efficiency, and profitability with application of phosphorus fertilizer and inoculants on smallholder farms in sub-Saharan Africa
Get PDFAlthough soybean is emerging as an important commercial crop in sub-Saharan Africa (SSA), its productivity on smallholder farms is very low. Soybean requires application of phosphorus (P) fertilizer and inoculation with the right rhizobium strains to achieve optimum biological nitrogen fixation and higher yields. However, subsistence farmers in SSA rarely invest in P fertilizers and inoculants due to lack of knowledge of their use and benefits. Most of the early reports on soybean in SSA have been based on work on research stations; hence, information is lacking on the profitability of fertilizer and inoculant use on smallholder farms in SSA. The main hypothesis of the present study was that the combined application of P and inoculants significantly reduces yield risks and increases P use efficiency and profitability compared with P fertilizer alone under smallholder farm conditions. We analyzed a data set of over 2,800 observations from on-farm demonstrations across Ghana, Kenya, Malawi, Rwanda, Tanzania, Uganda, and Zambia. Soybean yields, the partial factor productivity of P (PFPP), agronomic efficiency of P (AEP), and the value cost ratio (VCR) were significantly improved by the combined application of P fertilizer with inoculants than with P fertilizer alone. Combining P and inoculants increased yields over P alone by 17.3% in Kenya, 21.4% in Zambia, 25.7% in Ghana, 56.4% in Tanzania, and 57.1% in Malawi. However, soil organic matter was an important determinant of yield response and P use efficiency. The VCR increased linearly with increasing AEP in P + inoculant (R2 = 0.829) and less so with P fertilizer alone (R2 = 0.672). Net present values were positive in all countries, indicating that investments in P fertilizer and inoculants will generate profits over time. In order to increase uptake of fertilizers and inoculants among subsistence farmers and make soybean production more profitable, appropriate policies and market incentives need to be created
Functional and biotechnological cues of potassium homeostasis for stress tolerance and plant development
No full textPotassium (K+) is indispensable for the regulation of a plethora of functions like plant metabolism, growth, development, and abiotic stress responses. K+ is associated with protein synthesis and entangled in the activation of scores of enzymes, stomatal regulation, and photosynthesis. It has multiple transporters and channels that assist in the uptake, efflux, transport within the cell as well as from soil to different tissues, and the grain filling sites. While it is implicated in ion homeostasis during salt stress, it acts as a modulator of stomatal movements during water deficit conditions. K+ is reported to abate the effects of chilling and photooxidative stresses. K+ has been found to ameliorate effectively the co-occurrence of drought and high-temperature stresses. Nutrient deficiency of K+ makes leaves necrotic, leads to diminished photosynthesis, and decreased assimilate utilization highlighting the role it plays in photosynthesis. Notably, K+ is associated with the detoxification of reactive oxygen species (ROS) when plants are exposed to diverse abiotic stress conditions. It is irrefutable now that K+ reduces the activity of NADPH oxidases and at the same time maintains electron transport activity, which helps in mitigating the oxidative stress. K+ as a macronutrient in plant growth, the role of K+ during abiotic stress and the protein phosphatases involved in K+ transport have been reviewed. This review presents a holistic view of the biological functions of K+, its uptake, translocation, signaling, and the critical roles it plays under abiotic stress conditions, plant growth, and development that are being unraveled in recent times
Farmers’ selection cues in cowpea for vegetable use in eastern Uganda
Get PDFA participatory cowpea varietal selection was carried out in Eastern Uganda in Kumi district among farmers (n=30) in the sub-Counties of: Ongino, Kumi and Kanyum. A range of opinions were collected to identify farmers’ selection criteria based on different sensory attributes and their most preferred genotypes for vegetable use. A preference analysis was carried out to obtain quantitative preference scores of each plot. This was followed by organoleptic tests which included attributes like taste, aroma and texture of the genotypes at the vegetative and immature R4 stages. Focus group discussions (FGDs) were also held to find consensus of the independent evaluations made by individual farmers. Data for sixteen (16) cowpea genotypes were collected at the different above mentioned stages. Quantitative data were analyzed based on farmers’ scores made on the different evaluated attributes and ANOVA was used to provide mean differences between location, gender and genotype at a significant level of 5%. Preference score for each of the varieties tested was determined and presented. Data from FGDs were grouped, similarities and differences were later determined depending on their level of importance to the farmers. Significant differences (p<0.05) in farmer choices were observed for leaf taste, immature pod aroma, taste and texture; mature pod aroma, taste between farmer groups, age genotype and gender. Irrespective of age, gender, farmer group and genotype, farmers seemed to give more importance to the smooth texture, little hard leaves when chewing, sweet taste with a mild aroma (leaves) and a moderate aroma (pods). Majority (9%) of the farmers preferred Ebelat (landrace) at V4 stage; this was followed by Danila (8.7%). On the other hand, UCUCOW1 (13% at immature and 10.2% at mature cooked R4 stage) followed by Ebelat (9% and 9.8% for immature and mature R4 stage, respectively) were preferred by majority of the farmers. In terms of sensory attributes, farmers preferred genotypes with sweet taste, moderate aroma and tender texture. The information is a baseline for understanding key farmer selection criteria in utilization of cowpea as a vegetable which can be used in generating a demand-led variety design for the crop
Discovery of Major Quantitative Trait Loci and Candidate Genes for Fresh Seed Dormancy in Groundnut
Get PDFSpanish bunch groundnut varieties occupy most of the cultivated area in Asia and Africa, and these varieties lack required 2-3 weeks of fresh seed dormancy (FSD) hampering kernel quality. Genomic breeding can help to improve commercial groundnut cultivars for FSD in a shorter time with greater precision. In this regard, a recombinant inbred line (RIL) population from the cross ICGV 02266 (non-dormant) × ICGV 97045 (dormant) was developed and genotyped with a 5 K mid-density genotyping assay. A linkage map was constructed with 325 SNP loci spanning a total map length of 2335.3 cM and five major QTLs were identified on chromosomes Ah01, Ah11, Ah06, Ah16 and Ah17. Based on differential gene expression using transcriptomic information from dormant (Tifrunner) and non-dormant (ICGV 91114) genotypes, histone deacetylases, histone-lysine N-methyltransferase, cytochrome P450, protein kinases, and ethylene-responsive transcription factor were identified as key regulators involved in the hormonal regulation of dormancy. Six Kompetitive Allele Specific PCR (KASP) markers were successfully validated in the diverse panel including selected RILs of the same population and germplasm lines. These validated KASP markers could facilitate faster breeding of new varieties with desired dormancy using marker-assisted early generation selection
Molecular Approaches for Removal of Toxic Metal by Genetically Modified Microbes
No full textFor a long time, microbes have flourished in metal-contami-
nated environments and played a vital role in their speciation. Metals often have a key role in defining various catalyzing reactions as well as maintaining the structure of the microbial cell. However, certain metals do not contribute to the microbial metabolism and are instead highly toxic. Further, the use of metals in metabolic pathways depends greatly on the species of the metal. Numerous microorganism (bacteria, fungi, yeast, and algae) belonging to varying species were identified that possess the ability to tolerate high heavy metal concentrations
in the environment (Ghosh, 2018; Bloch et al., 2021). Microbes exhibit different mechanisms for resistance against heavy metals such as biosorption of metal ions, bioaccumulation, and biotransformation of metal species. The microbial species also have the ability to cope with diverse aerobic, anaerobic, and thermophilic environments. Microbial biomass is often used to enhance metal-binding capacity in an aqueous solution and eventually for recovery of the metals. However, the use of microbes such as bacteria as a biosorbent can be easily altered with natural materials like resins, which have shown similar efficiencies (Valls and De Lorenzo, 2002
Higher sowing density of pearl millet increases productivity and water use efficiency in high evaporative demand seasons
Get PDFIntroduction: Pearlmillet is themain subsistence crop for smallholder farmers systemswhere it is grown at low plant density. Intensifying pearl millet cultivation could boost productivity although it may have trade-offs. Increasing planting density would indeed increase the leaf area and the related water budget, whereas a denser canopy could create a more favorable canopymicroclimate to the benefit of the water use efficiency (WUE) of the crops. The first aim of this work was to test the yield response of popular pearlmillet varieties to an increased density and to assess possible genotypic variation in this response. The second aim was to measure the water use and the WUE of the crop in different densities.
Method: To this end we designed several field and lysimetric experiments To increase the robustness of the results, these trials were carried out in India and Senegal, using two independent sets of genotypes adapted to both sites.
Results: In the field, the higher sowing density significantly increased yield in all genotypes when trials were carried out in high evaporative demand conditions. There was no genotype x density interaction in these trials, suggesting no genotypic variation in the response to density increase. The high-density treatment also decreased the vapor pressure deficit (VPD) in the canopies, both in the field and in the lysimeter experiments. In the lysimeter trials, although the higher density treatment increased water use, the resulting increase in biomass was proportionally higher, hence increasingWUE of the crops in all genotypes under high density. The increase in yield under high density was closely related to the increase in WUE, although this link was more tight in the high- than in the low evaporative demand seasons. This confirmed a strong environmental effect on the response to density of all genotypes tested.
Discussion: Although they did not open a scope for breeding density tolerant cultivars, these results highlight the possibility to improve pearl millet yield by increasing the density, targeting specifically areas facing high evaporative demand
Seed coat mediated resistance against Aspergillus flavus infection in peanut
Get PDFToxic metabolites known as aflatoxins are produced via certain species of the Aspergillus genus, specifically
A. flavus, A. parasiticus, A. nomius, and A. tamarie. Although various pre- and post-harvest strategies have been
employed, aflatoxin contamination remains a major problem within peanut crop, especially in subtropical environments.
Aflatoxins are the most well-known and researched mycotoxins produced within the Aspergillus genus (namely Aspergillus flavus) and are classified as group 1 carcinogens. Their effects and etiology have been extensively researched and aflatoxins are commonly linked to growth defects and liver diseases in humans and livestock. Despite the known importance of seed coats in plant defense against pathogens, peanut seed coat mediated defenses against Aspergillus flavus resistance, have not received considerable attention. The peanut seed coat (testa) is primarily composed of a complex cell wall matrix consisting of cellulose, lignin, hemicellulose, phenolic compounds, and structural proteins. Due to cell wall desiccation during seed coat maturation, postharvest A. flavus infection occurs without the pathogen encountering any active genetic resistance from the live
cell(s) and the testa acts as a physical and biochemical barrier only against infection. The structure of peanut seed
coat cell walls and the presence of polyphenolic compounds have been reported to inhibit the growth of A. flavus
and aflatoxin contamination; however, there is no comprehensive information available on peanut seed coat
mediated resistance. We have recently reviewed various plant breeding, genomic, and molecular mechanisms, and management practices for reducing A. flavus infection and aflatoxin contamination. Further, we have also proved that seed coat acts as a physical and biochemical barrier against A. flavus infection. The current review focuses specifically on the peanut seed coat cell wall-mediated disease resistance, which will enable researchers to understand the mechanism and design efficient strategies for seed coat cell wall-mediated resistance against A. flavus infection and aflatoxin contamination