Diverse Agro-ecologies Research Articles

Assessment of maize-cowpea intercropping response to row orientation in diverse agro-ecologies of Côte d'Ivoire

The stability of cropping systems in a changing climate context depends on numerous factors, including row orientation, to optimize the use of environmental resources. This study aimed to evaluate the performance of agricultural systems based on the row orientation of cowpea (Vigna unguiculata) and maize (Zea mays) in three different ecological conditions in Côte d’Ivoire, in 2020 and 2021. An experimental design with plots divided into three complete randomized blocks with six subplots per block and three repetitions was set up, varying the row orientation in intercropping and monoculture. Row orientation, cropping system used, and ecological zone significantly influenced crop yield and its components. In intercropping, cowpea (tiligré) showed the best yields when oriented North–South (NS) in the tropical rainforest zone and the sub-Sudanian savannah, while East–West (EW) orientation was optimal in the forest-savannah mosaic zone. In contrast, maize (GMRP18) yielded the best in intercropping when rows were oriented East–West, regardless of the season. In monoculture, cowpea yielded best when oriented EW in the tropical rainforest zone (488.17 kg ha−1) and in the forest-savannah mosaic zone (1262.12 kg ha−1), while NS orientations were preferable (228.6 and 259.54 kg ha−1) in the sub-Sudanian savannah zone. For maize monoculture, EW orientation was also preferable. Throughout the study, for both seasons, the highest yield advantages in maize-cowpea intercropping were obtained in EW orientation, regardless of the ecological zone. Overall, the forest-savannah mosaic zone yielded the best cowpea yields (1262.12 and 663.9 kg ha−1).

The Exploration and Utilization of Coffee (Coffea arabica L.) Genetic Resource in Its Center of Origin

Coffee, which is the most popular soft drink in the world, belongs to the genus Coffea in the Rubiaceae family. About 124 species are known in this genus, whereas Coffea arabica L. and Coffea canephora are the two most widely cultivated species worldwide. Coffea arabica is the only tetraploid species in the genus coffea and is self-fertile, while other species are diploid and generally self-incompatible. Ethiopia is the center of origin and diversity for arabica coffee, which is the only species cultivated in the country. The availability of wide genetic variability among the indigenous coffee and the diverse agro-ecologies in the country provided immense possibilities to improve the crop for desirable agronomic and breeding interest traits. Cognizant of this and the occurrence of coffee berry disease (CBD) in Ethiopia for the first time, a coffee breeding program was initiated in the 1970’s aiming at exploiting the available genetic diversity and developing productive varieties combining disease resistance, best quality, and other desirable characteristics. Coffee genetic resource collection, characterization, evaluation, conservation and genetic studies are among the major breeding activities undertaken so far by designing and implementing different breeding strategies following the conventional breeding approach. So far, outstanding achievements have been recorded in collecting 7130 germplasm accessions, generating basic information on the genetics aspects, and developing 44 improved varieties of which seven are F1 hybrids and identifying 149 elite promising genotypes for further evaluation to develop and release a new varieties. Extensive collection of coffee genetic resources from unaddressed areas, and application of molecular breeding techniques such as marker-assisted selection and breeding for stress tolerance, among others, would be the main focus areas of future coffee breeding programs.

Relevance of molecular systematics in insect pest management

Relevance of molecular systematics in insect pest management

Potential of Temperate, Tropical, and Sub-Tropical Exotic Maize Germplasm for Increased Gains in Yield Performance in Sub-Tropical Breeding Programs

Exotic germplasm (i.e., germplasm beyond the breeder’s target area) has traditionally been used to broaden the genetic base of local (germplasm within the breeder’s target area) populations, but little has been done to assess gains that could be induced by this breeding practice in the sub-tropical regions of Africa. Here, eight maize (Zea mays L.) inbred lines developed from pedigree crosses of exotic and local (i.e., sub-tropically adapted lines; STALs) were inter-mated together with six elite STALs, in a partial diallel mating scheme, in order to depict yield gains that can be made when exotic genes are integrated within the sub-tropical maize germplasm pool. The crossing scheme yielded a total of 91 F1s which were evaluated together with nine commercial checks in multi-environmental trials (METs) at eight locations representing agro-ecologies in which maize is predominantly grown in Zimbabwe. Across site Analysis of Variance (ANOVA) showed differences in grain yield (GY) performance of the F1s. Significant genotype x environment effects was also detected for GY (i.e., GEI; p < 0.05). F1s of parents with a temperate background [i.e., P7 (S) x P2 (T)] showed the highest GY potential (e.g., G44; GY = 10.52 tha−1). Apart from showing high GY potential, G44 also demonstrated to be stable across diverse agro-ecologies and to mature earlier than the best commercial check hybrid. In conclusion, incorporation of exotic genes, especially those from temperate regions, may improve the yielding ability and stability and can introduce earliness in the maturity of maize populations in sub-tropical regions.

Silage maize as a potent candidate for sustainable animal husbandry development-perspectives and strategies for genetic enhancement.

Maize is recognized as the queen of cereals, with an ability to adapt to diverse agroecologies (from 58oN to 55oS latitude) and the highest genetic yield potential among cereals. Under contemporary conditions of global climate change, C4 maize crops offer resilience and sustainability to ensure food, nutritional security, and farmer livelihood. In the northwestern plains of India, maize is an important alternative to paddy for crop diversification in the wake of depleting water resources, reduced farm diversity, nutrient mining, and environmental pollution due to paddy straw burning. Owing to its quick growth, high biomass, good palatability, and absence of anti-nutritional components, maize is also one of the most nutritious non-legume green fodders. It is a high-energy, low-protein forage commonly used for dairy animals like cows and buffalos, often in combination with a complementary high-protein forage such as alfalfa. Maize is also preferred for silage over other fodders due to its softness, high starch content, and sufficient soluble sugars required for proper ensiling. With a rapid population increase in developing countries like China and India, there is an upsurge in meat consumption and, hence, the requirement for animal feed, which entails high usage of maize. The global maize silage market is projected to grow at a compound annual growth rate of 7.84% from 2021 to 2030. Factors such as increasing demand for sustainable and environment-friendly food sources coupled with rising health awareness are fueling this growth. With the dairy sector growing at about 4%-5% and the increasing shortage faced for fodder, demand for silage maize is expected to increase worldwide. The progress in improved mechanization for the provision of silage maize, reduced labor demand, lack of moisture-related marketing issues as associated with grain maize, early vacancy of farms for next crops, and easy and economical form of feed to sustain household dairy sector make maize silage a profitable venture. However, sustaining the profitability of this enterprise requires the development of hybrids specific for silage production. Little attention has yet been paid to breeding for a plant ideotype for silage with specific consideration of traits such as dry matter yield, nutrient yield, energy in organic matter, genetic architecture of cell wall components determining their digestibility, stalk standability, maturity span, and losses during ensiling. This review explores the available information on the underlying genetic mechanisms and gene/gene families impacting silage yield and quality. The trade-offs between yield and nutritive value in relation to crop duration are also discussed. Based on available genetic information on inheritance and molecular aspects, breeding strategies are proposed to develop maize ideotypes for silage for the development of sustainable animal husbandry.

Genetic and genomic interventions in crop biofortification: Examples in millets.

Micronutrient malnutrition is a serious threat to the developing world's human population, which largely relies on a cereal-based diet that lacks diversity and micronutrients. Besides major cereals, millets represent the key sources of energy, protein, vitamins, and minerals for people residing in the dryland tropics and drought-prone areas of South Asia and sub-Saharan Africa. Millets serve as multi-purpose crops with several salient traits including tolerance to abiotic stresses, adaptation to diverse agro-ecologies, higher productivity in nutrient-poor soils, and rich nutritional characteristics. Considering the potential of millets in empowering smallholder farmers, adapting to changing climate, and transforming agrifood systems, the year 2023 has been declared by the United Nations as the International Year of Millets. In this review, we highlight recent genetic and genomic innovations that can be explored to enhance grain micronutrient density in millets. We summarize the advances made in high-throughput phenotyping to accurately measure grain micronutrient content in cereals. We shed light on genetic diversity in millet germplasm collections existing globally that can be exploited for developing nutrient-dense and high-yielding varieties to address food and nutritional security. Furthermore, we describe the progress made in the fields of genomics, proteomics, metabolomics, and phenomics with an emphasis on enhancing the grain nutritional content for designing competitive biofortified varieties for the future. Considering the close genetic-relatedness within cereals, upcoming research should focus on identifying the genetic and genomic basis of nutritional traits in millets and introgressing them into major cereals through integrated omics approaches. Recent breakthroughs in the genome editing toolbox would be crucial for mainstreaming biofortification in millets.

Multilocational evaluation of white yam genotypes using gge bi-plot methodology.

Yams are Cultivated in diverse agroecologies and there is evidence of strong genotype and environment interaction. This has necessitated the evaluation of new yam genotypes in multi-locational trials. Five new white yam genotypes were evaluated in different locations of major yam producing areas; Umudike, Nsukka, Ubiaja, Abuja and Katsina-Ala, to test the performance and stability of these genotypes across the environments using GGE bi-plot software. The GGE bi-plot generated several graphic bi-plots which showed Umudike, Nsukka, Ubiaja and Katsina-Ala belonging to one mega- environment while Abuja and Ubiaja belong to another. The GGE bi-plot also showed the discriminating and non-discriminating environments. Katsina-Ala was the most discriminating environment while Nsukka was the least. A test environment that lacks discriminating ability lacks the capacity to provide information about the genotype being used. Such environment lacks usefulness and should be discarded as a test environment Katsina-Ala, with the longest vector is the most discriminating. This is followed by Ubiaja, Umudike and Abuja in that order. Nsukka is the least discriminating.

Pulses in conservation agriculture: An approach for sustainable crop production and soil health

Conservation Agriculture (CA) has emerged as a pivotal paradigm in modern agriculture, emphasizing sustainable practices to enhance crop productivity while preserving soil health and natural resources. Conservation agriculture relies on three key principles: including minimum soil disturbances, permanent soil covers with crop residue and promoting crop/species diversification. Pulses possess unique attributes, such as biological nitrogen f ixation, leaf litter fall, nutrient-enriched crop residues, and a deep root system with enhanced rhizospheric activities, which make them conducive to CA principles. In the agriculture systems of southern Asia, the continuous practice of conventional input-intensive cereal-dominated production has largely contributed to soil degradation, depletion of underground water resources, and reduced land and water productivity, ultimately jeopardizing sustainable food production. Given this, researchers emphasize the pivotal role of crop diversification including pulses in the system in order to conserve natural resources, foster soil health, and sustain crop productivity. Experimental f indings from diverse agro-ecologies provide evidence that the integration of pulses in CA not only contributes to enhanced agricultural sustainability but also holds the potential to address food security and nutrition challenges in an era marked by climate uncertainties and environmental degradation. Given the growing significance of pulses in CA, there is a pressing need for more systematic studies across diverse agro-regions to maximize the benefits of CA. This article highlights the important role of pulses in CA, focusing on its potential benefits pertaining to sustainable crop production, resource conservation and soil health.

Agro-Ecology Specific Strategies for Resilient Rainfed Production Systems

Rainfed agriculture, practiced in diverse agroecologies contributes, immensely to India’s food basket. However, rainfed agriculture in India is constrained with many biophysical and socioeconomic challenges, particularly changing climate and rainfall variability. Managing climate risks, enhancing productivity and profitability, further achieving resilience of the rainfed production systems is need of the hour. To address these, agro-ecology specific crop alignment, agro-ecology specific potential crop zoning and diversifying within farm for sustainable intensification and real-time contingency planning implementation are the key strategies.

Selection of Surrogates For Drought Resilience In Temperate Maize (Zea Mays L.)

Drought is one of the major constraints affecting the economic yield of maize worldwide. Present study was carried out to select the surrogates for drought resilience in 70 maize landraces collected from diverse agro-ecologies of Kashmir Himalayas. Significant variation was observed among the genotypes for all the traits under well-watered and drought conditions. Due to the drought stress, the highest reduction was observed for the canopy temperature (175.18%), followed by root volume (69.77%), top root biomass (69.1%), shoot biomass (67.2%), bottom root biomass (53.75%), chlorophyll content (22.85 SPAD units) and shoot height (21.63%). The reduction was also recorded for other traits like shoot to total biomass ratio (2.70%), relative water content (13.42 %), cell membrane stability (17.33%) and rooting depth (19.86%). Root to total biomass ratio was found to increase in response to drought stress (7.69%). A positive significant correlation was observed between grain yield and root volume, top root biomass, bottom root biomass, rooting depth, root to total biomass, chlorophyll content, cell membrane stability, canopy temperature depression and relative water content. These can be used for selection of appropriate surrogates of drought tolerant genotypes. The landraces viz., KD-L35, KD-L37, KD-L19, KD-L23, KD-L17, KD-L21, KD-L46, KD-L43, KD-L29, KD-L25 and KD-L38 showed promising performance under drought for most of the surrogates identified. The landraces selected can be used as sources of novel and/or favourable alleles to breed for climate resilient maize cultivars. Bangladesh J. Bot. 51(3): 487-498, 2022 (September)

Effect of Furrow Irrigation Methods and Drip Irrigation System on Yield and Yield Components of Different Crops

This paper was focused on reviewing of different documents and research findings from studies conducted on furrow irrigation methods and drip irrigation methods on different crop types. The reviewing coverage of the research findings conducted on comparison of furrow irrigation and drip irrigation was between 2012 and 2021. Approaches followed on reviewing the papers on different furrow irrigation system type and drip irrigation methods were through reviewing journals from websites and research output reports. On this paper review, achievements of comparison of furrow irrigation and drip irrigation under diverse agro-ecologies are highlighted based on the current knowledge from available sources. Based on different findings the use of drip irrigation method was best option for both crop yield increment and water use efficiency .So in current research findings in order to use drip irrigation for crop production purpose was best practice method due to year to year climate change and drought occurrences key solutions to avoid crop yield collapse and failure. But in order to use drip irrigation system the cost drip materials and awareness of farms are the key problem of different findings are indicated. Keywords: drip, furrow irrigation, crop DOI: 10.7176/JRDM/88-02 Publication date: October 31 st 2022

Multi-location evaluation of mungbean (Vigna radiata L.) in Indian climates: Ecophenological dynamics, yield relation, and characterization of locations.

Crop yield varies considerably within agroecology depending on the genetic potential of crop cultivars and various edaphic and climatic variables. Understanding site-specific changes in crop yield and genotype × environment interaction are crucial and needs exceptional consideration in strategic breeding programs. Further, genotypic response to diverse agro-ecologies offers identification of strategic locations for evaluating traits of interest to strengthen and accelerate the national variety release program. In this study, multi-location field trial data have been used to investigate the impact of environmental conditions on crop phenological dynamics and their influence on the yield of mungbean in different agroecological regions of the Indian subcontinent. The present attempt is also intended to identify the strategic location(s) favoring higher yield and distinctiveness within mungbean genotypes. In the field trial, a total of 34 different mungbean genotypes were grown in 39 locations covering the north hill zone (n = 4), northeastern plain zone (n = 6), northwestern plain zone (n = 7), central zone (n = 11) and south zone (n = 11). The results revealed that the effect of the environment was prominent on both the phenological dynamics and productivity of the mungbean. Noticeable variations (expressed as coefficient of variation) were observed for the parameters of days to 50% flowering (13%), days to maturity (12%), reproductive period (21%), grain yield (33%), and 1000-grain weight (14%) across the environments. The genotype, environment, and genotype × environment accounted for 3.0, 54.2, and 29.7% of the total variation in mungbean yield, respectively (p < 0.001), suggesting an oversized significance of site-specific responses of the genotypes. Results demonstrated that a lower ambient temperature extended both flowering time and the crop period. Linear mixed model results revealed that the changes in phenological events (days to 50 % flowering, days to maturity, and reproductive period) with response to contrasting environments had no direct influence on crop yields (p > 0.05) for all the genotypes except PM 14-11. Results revealed that the south zone environment initiated early flowering and an extended reproductive period, thus sustaining yield with good seed size. While in low rainfall areas viz., Sriganganagar, New Delhi, Durgapura, and Sagar, the yield was comparatively low irrespective of genotypes. Correlation results and PCA indicated that rainfall during the crop season and relative humidity significantly and positively influenced grain yield. Hence, the present study suggests that the yield potential of mungbean is independent of crop phenological dynamics; rather, climatic variables like rainfall and relative humidity have considerable influence on yield. Further, HA-GGE biplot analysis identified Sagar, New Delhi, Sriganganagar, Durgapura, Warangal, Srinagar, Kanpur, and Mohanpur as the ideal testing environments, which demonstrated high efficiency in the selection of new genotypes with wider adaptability.

Review on Heterosis and Combining Ability Study for Yield and Morphological Characters of Coffee (Coffea arabica L) in Ethiopia

Ethiopia is both the center of origin and diversification of Coffee arabica. Despite the existence of high genetic diversity in coffee population that provides immense opportunities for improvement program, shortage of improved varieties (pure line and hybrid varieties) is the major one. It is obvious that research work carried out so far on coffee genetics and breeding was not adequate to address these diverse agro-ecologies of the country. Heterosis and combining ability studies are some of the basic breeding tools to address such problems. Some studies had been focused on assessment of heterosis and combining ability analysis for yield and morphological characters of coffee in Ethiopia and the presence of heterosis was reported in crosses of selected indigenous C. arabica L. varieties in Ethiopia under different set of studies mainly due to presence of diverse parental lines. These results clearly suggested that the possibility to bring significant coffee improvement through heterosis and combining ability analysis. Therefore, continuous crossing program should be required to acquire many more cross combinations for intensive and extensive evaluation to develop better performing and high yielding hybrids for Ethiopian origin coffee. Keywords: Coffee Arabica, morphological traits, yield, Heterosis and combining ability DOI: 10.7176/JEES/12-7-02 Publication date: July 31 st 2022

Field evaluation of slow-release nitrogen fertilizers and real-time nitrogen management tools to improve grain yield and nitrogen use efficiency of spring maize in Nepal

Several innovative fertilizers and application methods, along with different decision support tools have been developed to improve nitrogen use efficiency (NUE) and crop yields, but their comparative study in maize is yet to be done in Nepal. Thus, we evaluated different slow-release N fertilizers and decision-making tools for real-time N management compared with the common urea on their effectiveness in increasing NUE, grain yield and economic return of spring maize (Zea mays L. cv. Rampur Hybrid-10). A field trial was conducted at Dang Valley of Nepal in a Randomized complete block design with three replications and seven treatments; N omission- (0 kg N ha−1), normal urea at 120 kg N ha−1 (recommended dose, N120), and 180 kg N ha−1(N180), Polymer Coated Urea (PCU- 90 kg N ha−1), Urea Briquette-deep placement (UDP- 90 kg N ha−1), GreenSeeker (GS- 143 kg N ha−1) and Leaf Color Chart based N management (LCC- 143 kg N ha−1). N application based on decision support tools (LCC and GS) and innovative fertilizers (UDP, PCU) yielded 17.35–45.81% more grain yield than recommended dose (RDF). The real time nitrogen application through LCC and GreenSeeker and slow release N fertilizer (PCU and UDP) resulted in higher agronomic efficiency of nitrogen- AEN (21.30–27.82 kg grain kg−1 N) compared to RDF (12.15 kg grain kg−1 N) and N180 (19.87 kg grain kg−1 N). UDP, with 25% less N compared to RDF, resulted in higher grain yield (5.25 t ha−1), partial factor productivity of N– PFPN (58.37 kg grain kg−1 N) and AEN (27.82 kg grain kg−1 N). Based on the economic return and ease in the application, both UDP and LCC based N application seem promising in Nepalese conditions. However, their effectiveness should be validated across diverse agro-ecologies, soil types and climatic conditions for a general recommendation.

Expression of Nutritional Traits in Vegetable Cowpea Grown under Various South African Agro-Ecological Conditions.

Cowpea (Vigna unguiculata L.), a traditional legume food crop indigenous to Africa, has potential as both a vegetable and grain crop in contributing to dietary diversity to support health and address malnutrition, especially for those relying heavily on wheat, maize, and rice. The expression of nutritional traits (protein content and concentrations of iron (Fe), zinc (Zn), and manganese (Mn)) in cowpea leaves was evaluated over diverse agro-ecologies of South Africa and typical agronomic practices of smallholder farmers. The genotypes evaluated displayed genetic variation for all four traits. The mean values of Fe, Zn, Mn and protein content varied from 33.11 to 69.03 mg.100.g−1; 4.00 to 4.70 mg.100.g−1; and 14.40 to 19.63 mg.100.g−1 and 27.98 to 31.98%, respectively. The correlation analysis revealed significant degree of positive association between protein and Zn (r = 0.20), while negative associations were observed between Mn and protein (−0.46) and between Mn and Fe (r = −0.27). Furthermore, the expression of these important nutrient traits was influenced by the climatic conditions represented by six environments (location by year combinations) as is typical of ‘quality’ traits. Additionally, genotype-by-environment interaction effects were detected, suggesting that local soil properties and soil health may play a role in nutritional content in plants, perhaps particularly for legume crops that rely on symbiotic relationships with soil bacterial populations to fix nitrogen, which is crucial to protein formation. Further studies are needed to understand how to coordinate and align agronomic and soil management practices in vegetable cowpea production, especially those workable for the smallholder farmer, to realize the full genetic potential and nutritional value of improved vegetable cowpea varieties.

Novel GBS-Based SNP Markers for Finger Millet and Their Use in Genetic Diversity Analyses.

Eleusine coracana (L.) Gaertn., commonly known as finger millet, is a multipurpose crop used for food and feed. Genomic tools are required for the characterization of crop gene pools and their genomics-led breeding. High-throughput sequencing-based characterization of finger millet germplasm representing diverse agro-ecologies was considered an effective method for determining its genetic diversity, thereby suggesting potential candidates for breeding. In this study, the genotyping-by-sequencing (GBS) method was used to simultaneously identify novel single nucleotide polymorphism (SNP) markers and genotype 288 finger millet accessions collected from Ethiopia and Zimbabwe. The accessions were characterized at individual and group levels using 5,226 bi-allelic SNPs, with a minimum allele frequency (MAF) of above 0.05, distributed across 2,500 scaffolds of the finger millet reference genome. The polymorphism information content (PIC) of the SNPs was 0.23 on average, and a quarter of them have PIC values over 0.32, making them highly informative. The grouping of the 288 accessions into seven populations based on geographic proximity and the potential for germplasm exchange revealed a narrow range of observed heterozygosity (Ho; 0.09–0.11) and expected heterozygosity (He) that ranged over twofold, from 0.11 to 0.26. Alleles unique to the different groups were also identified, which merit further investigation for their potential association with desirable traits. The analysis of molecular variance (AMOVA) revealed a highly significant genetic differentiation among groups of accessions classified based on the geographic region, country of origin, days to flowering, panicle type, and Al tolerance (p < 0.01). The high genetic differentiation between Ethiopian and Zimbabwean accessions was evident in the AMOVA, cluster, principal coordinate, and population structure analyses. The level of genetic diversity of finger millet accessions varies moderately among locations within Ethiopia, with accessions from the northern region having the lowest level. In the neighbor-joining cluster analysis, most of the improved cultivars included in this study were closely clustered, probably because they were developed using genetically less diverse germplasm and/or selected for similar traits, such as grain yield. The recombination of alleles via crossbreeding genetically distinct accessions from different regions of the two countries can potentially lead to the development of superior cultivars.

Genetic variability and population structure of Leucinodes orbonalis (Guenée), a severe insect pest of brinjal in India

Aim: The present study was undertaken to provide valuable insights regarding population genetic structure of Leucinodes orbonalis from diverse agro-ecologies of India. Methodology: Molecular characterization of L. orbonalis populations collected from five major agro-climatic zones of India was carried out using mitochondrial cytochrome oxidase I (COI) gene. Collected specimens were subjected to DNA extractions, partial PCR amplification and sequencing of the target gene, and multiple sequence alignments. Results: The results showed very less diversity in the nucleotide positions of the COI sequences of 79 studied specimens, with a low number of segregating sites (30), nucleotide diversity (0.00438) and overall mean genetic distance (0.004 ± 0.001). The significant negative values of neutrality tests and unimodal mismatch distribution supported the demographic expansion theory in Indian L. orbonalis. Analysis of the molecular variance revealed that 93.13% of the genetic variation was within populations, and the variation among populations was only 6.87%. The pairwise genetic differentiation was also found to be low to moderate between most of the populations. Multiple haplotypes were recorded from all the populations, and both neighbour-joining tree as well as the haplotype network showed that clustering of the haplotypes was independent of the geographical location. Interpretation: Thus, it can be inferred that Indian populations of L. orbonalis have very low genetic variation levels concerning the COI gene. There is a possible occurrence of stable inherited gene flow among populations, thereby reducing genetic variation in India.

Diversity and Phosphate Solubilization Efficiency of Phosphate Solubilizing Bacteria Isolated from Semi-Arid Agroecosystems of Eastern Kenya.

Phosphorus (P) is a major nutrient required for plant growth but it forms complexes with other elements in soil upon application. A cost-effective way of availing P to plants is by use of Phosphate Solubilizing Bacteria (PSB). There is a wide range of PSB suited for diverse agro-ecologies. A large part of Eastern Kenya especially the lower altitude regions are semi-arid with nutrient depleted soils and predominated by low-income smallholders farmers who do not afford costly inorganic fertilizers. To alleviate poor soil nutrition in this agroecosystem, we sought to study the diversity of phosphate solubilizing bacteria and their phosphate solubilization efficiency. The bacteria were selectively isolated in Pikovskaya’s agar media. Bacterial colonies were enumerated as Colony Forming Units and morphological characterization determined by analyzing morphological characteristics. Genetic characterization was determined based on sequencing of 16S rRNA. A total of 71 PSB were isolated and they were placed into 23 morphological groups. Correlation analysis showed a negative correlation between phosphate solubilizing bacteria and the levels of phosphorus, iron, calcium, magnesium and soil pH. Analysis of 16S rRNA sequences revealed that the genetic sequences of the isolates matched the strains from the genera Burkholderia, Pseudomonas, Bacillus, Enterobacter, Pantoea, Paraburkholderia, Cronobacter, Ralstonia, Curtobacterium, and Massilia deposited in NCBI Database. Analysis of Molecular Variance showed that variation within populations was higher than that of among populations. Phosphate solubilization index values ranged between 1.143 and 5.883. Findings on biodiversity of phosphate solubilizing bacteria led to identification of 10 candidate isolates for plant growth improvement and subsequently, bio-fertilizer development.

Crop Response to Different Mulch Type and Furrow Irrigation Methods in Major Irrigated Areas of Ethiopia: A Review

The paper was focused on reviewing of different documents and research findings from studies conducted on interaction effect of different mulch type and furrow irrigation methods on different crop types on major irrigated area of the country. The coverage of the research findings conducted on mulch type and furrow irrigation method was between 2010 and 2021. Approaches followed on reviewing the papers on different mulch type and furrow irrigation methods were through reviewing journals from websites and research output reports. On this paper review, achievements of different mulch type for different furrow irrigation under diverse agro-ecologies are highlighted based on the current knowledge from available sources. Based on different findings the use of plastic mulch type was best option for both crop yield increment and soil moisture conservation .So in current research findings in order to use mulch for crop production purpose was best practice method due to year to year climate change and drought occurrences key solutions to avoid crop yield collapse and failure. Keywords: mulch, furrow irrigation, crop DOI: 10.7176/JRDM/80-01 Publication date: November 30 th 2021

Subterranean Microbiome Affiliations of Plantain (Musa spp.) Under Diverse Agroecologies of Western and Central Africa

Plantain (Musa spp.) is a staple food crop and an important source of income for millions of smallholder farmers in sub-Saharan Africa (SSA). However, there is a paucity of knowledge on soil microbial diversity in agroecologies where plantains are grown. Microbial diversity that increases plant performance with multi-trophic interactions involving resiliency to environmental constraints is greatly needed. For this purpose, the bacterial and fungal communities of plantain fields in high rainfall forests (HR) and derived savannas (SV) were studied using Illumina MiSeq for 16S rDNA and ITS amplicon deep sequencing. Microbial richness (α- and β-diversity), operational taxonomic units, and Simpson and Shannon–Wiener indexes (observed species (Sobs), Chao, ACE; P < 0.05) suggested that there were significant differences between HR and SV agroecologies among the most abundant bacterial communities, and some specific dynamic response observed from fungal communities. Proteobacteria formed the predominant bacterial phylum (43.7%) succeeded by Firmicutes (24.7%), and Bacteroidetes (17.6%). Ascomycota, Basidiomycota, and Zygomycota were the three most dominant fungal phyla in both agroecologies. The results also revealed an immense array of beneficial microbes in the roots and rhizosphere of plantain, including Acinetobacter, Bacillus, and Pseudomonas spp. COG and KEGG Orthology database depicted significant variations in the functional attributes of microbes found in the rhizosphere to roots. This result indicates that the different agroecologies and host habitats differentially support the dynamic microbial profile and that helps in altering the structure in the rhizosphere zone for the sake of promoting synergistic host-microbe interactions particularly under resource-poor conditions of SSA.