Early Production System Research Articles

Guidelines for reforming early childhood teacher production and development systems by applying competencies effecting the early childhood - Based conceptual innovation development

Guidelines for reforming early childhood teacher production and development systems by applying competencies effecting the early childhood - Based conceptual innovation development

Subsea-Systems Innovations Improve Heavy-Oil Production in Ultradeep Water

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 199003, “Subsea Systems Innovations and the Use of State-of-the-Art Subsea Technologies Help the Flow Assurance of Heavy-Oil Production in Ultradeep Water,” by Carlos Alberto Pedroso, SPE, Geraldo Rosa, SPE, and Priscilla Borges, Enauta Energia, et al., prepared for the 2020 SPE Latin American and Caribbean Petroleum Engineering Conference, Bogota, Colombia, 17–19 March. The paper has not been peer reviewed. Flow assurance in ultradeep water is a major issue for production. The Atlanta field, which produces heavy oil in ultradeep water, is a project combining several challenges: hydrates formation, emulsion tendency, scale formation, foaming, and high viscosities. The complete paper discusses innovations and technologies applied to make Atlanta a successful case of ultradeepwater heavy-oil production. Introduction Discovered in 2001, the Atlanta field is in the presalt exclusion area in the north of the Santos Basin, 185 km southeast of Rio de Janeiro, at a water depth of 1550 m. The postsalt reservoir is contained in the Eocene interval and is characterized by high net-to-gross sands (82–94%) with a high average porosity of 36% and high permeabilities in the range of 4–6 Darcies. These excellent rock properties, however, are offset by the poor quality of the Atlanta crude, which is heavy (14 °API), viscous (228 cp at reservoir conditions), and highly acidic. The development of the field took place in two phases, an early production system (EPS) and a definitive production system (DPS). First oil occurred in May 2018. The EPS is expected to last from 4 to 5 years, producing from three horizontal wells to a floating production, storage, and offloading vessel (FPSO) with a processing capacity of 30,000 BOPD. The DPS will consist of 12 horizontal producers tied to a larger-capacity FPSO.

Genotype and cytokinin effects on soybean yield and biological nitrogen fixation across soil temperatures

AbstractHigh nitrogen (N) supply is required for high‐yielding soybean, but low soil temperatures in either early production systems or cool environments delay nodulation and limit biological nitrogen fixation (BNF). Because cytokinins are key signalling hormones in mediating nodule formation and our initial controlled environment experiment indicated that seed cytokinin treatment increased early BNF and total nodule area, it was used in field trials. Cytokinin was applied (seed or foliar) to two commercial soybean genotypes (DM50I17 and DM40R16) in field trials with early (September and early November) and conventional (late November) sowing dates in Argentina. In the field, DMR50I7 achieved consistent yields across sowing dates because increased BNF compensated for limited soil N uptake in early sowing dates, also leading to 25% higher nitrogen use efficiency (NUE). Surprisingly, soil N uptake was more cold‐sensitive than BNF with greater and prolonged N fixation in early sowing, perhaps through delayed nodulation, leading to improved N harvest index. Cytokinin seed treatment increased BNF (26%) in DM40R16 especially in early sowing dates. Although cytokinin improved cold tolerance of BNF, this was not explained by altered nodulation and did not increase yield. Here we show genetic differences in N supply in commercial soybean genotypes and the importance of BNF to maintain yield in early sown soybean.

Atlanta Field: Producing Heavy and Viscous Oil in Ultradeepwater

SummaryAtlanta Field is a post-salt heavy-oil field located 185 km off the city of Rio de Janeiro, in Santos Basin, Brazil, at a water depth of approximately 1550 m. Atlanta, however, is not just another ultradeepwater heavy-oil field. Several additional challenges had to be overcome for its development, such as low reservoir overburden (800m), highly unconsolidated sandstone reservoir (36% porosity and 5,000 md permeability), heavy and viscous crude flow assurance (14 °API and 228 cp at initial reservoir conditions), high-naphthenic-acidity oil [total acid number (TAN) 10mg KOH/g], high-power artificial-lift pumping-systemrequirement (1,600 hp), and complex-topside crude facilities.The development of Atlanta Field was phased in two stages: an early production system (EPS), which is expected to last from four to five years and comprises three horizontal production wells; and a definitive production system (DPS), which will add nine wells to complete the development plan with 12 horizontal producers. The first two EPS wells were successfully constructed and tested during 2013 and 2014, proving the feasibility of surpassing the great challenges imposed by the field’s unique environment and enabling the beginning of the production phase of the field. The first oil occurred in May 2018 with these two wells producing to the floating production, storage, and offloading unit (FPSO) Petrojarl I. The third and last producer of the EPS was constructed in 2019 and began operation in June of the same year. More than five million barrels of oil were already produced to date.Marsili et al. (2015) described in detail the exploration and development phases of Atlanta Field, focusing on their challenges, the overcoming process, and solutions adopted. This current work intends to present an updated review of the paper, providing the most recent information related to the project with a subsequent focus on the production phase findings and results. Among others, the initial prediction and expectations will be compared with actual field performance. For all milestones achieved, the Atlanta project is considered a great success so far and a benchmark for the industry in this harsh and adverse environment.

Mini Review: Production and Economics Analysis Of Backyard Production of Tiger Grouper Epinephelus Fuscoguttatus Fingerlings in Situbondo, Indonesia

Application of backyard technology to produce tiger grouper fingerlings in the area of Situbondo is examined with emphasis on production system and economic structure. Complete hatcheries production system that employ full production systems from broodstock, maturation, spawning, larviculture and early nursery phase are common in this area. Natural spawning activities without the use of hormone or another chemical substance become the primary method to produce the larvae. Hatchery in Situbondo typically consist with concrete tank to culture the larva, sand filter and live food production tanks, including phytoplankton production system. While the nursery production system as an intermediate step between hatchery and grow-out production consist with concrete tank and grading system to reduce the size variation, cannibalism and to ensure there is no more than 30% difference in total length between the grade sizes within the culture tanks. The output of the economic analysis showed that with final survival rate about 10%, farmer in Situbondo still get a good annual return through the sales of fingerlings. From this situation, farmer still obtain high cash flow from backyard production system and about 69.06% rate of return to capital. Overall, backyard technology consists with hatchery and early nursery production system provide potential sources for poverty alleviation and support the sustainability of aquaculture production in Situbondo. Good economic structure and opportunity to participate in several government programs speed up the adoption of this technology and become an important chain for tiger grouper production system in Indonesia.

40 Years in the Campos Basin Lead to Wealth of Lessons Learned

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper OTC 28716, “Campos Basin Technologies Yard: 40 Years of Lessons Learned,” by M. Roberto, A.B. Coutinho, and A.R. Dos Santos, Petrobras, prepared for the 2018 Offshore Technology Conference, Houston, 30 April–3 May. The paper has not been peer reviewed. Copyright 2018 Offshore Technology Conference. Reproduced by permission. Over the last 40 years, the Campos Basin has been a major stage for technology development to push offshore oil and gas production to water depths (WDs) never before experienced. This paper presents a retrospective of the most-significant technologies developed and deployed in the Campos Basin for more than 80 production systems in more than 30 oil- and gas-field developments; a few of these milestones are described in this synopsis. Introduction The discovery of oil in the Campos Basin in 1974 occurred in the context of the 1973 world oil crisis and its effects on geopolitics and the global economy. In addition to the challenges associated with this period, a need existed to increase oil production while reducing costs, leading to a fast-track approach. The development of the Garoupa field, followed by the Pargo, Badejo, Namorado, Enchova, Bonito, and Pampo fields, revealed huge oil-production potential, minimizing Brazil’s need to import petroleum. The development and application of new technologies, such as early production systems (EPS), horizontal wells, tree standardization, flexible pipes, and subsea processing and boosting, allowed the necessary cost reduction and risk mitigation. Now, most of these technologies are consolidated and are used in new Brazilian discoveries, particularly in presalt areas. To speed the development of these technologies, a deep- and ultradeepwater technology program, the Technological Development Program for Deep water Production Systems (PROCAP), was initiated in 1986. PROCAP and its four versions—PROCAP 1000 (1000-m well depth), PROCAP 2000, PROCAP 3000, and PROCAP Future Vision, have since supported the development of Campos Basin technologies and the exploration of new frontiers. Technology Development Many technologies have been developed in the Campos Basin during the last 40 years in order to support the production, developing, revitalization, life extension, and decommissioning of its fields. The Campos Basin development has become successful because of a strong partnership between the operator and suppliers, academia, research centers, and other operators. Despite the challenges faced during the last 40 years, the Campos Basin served as an excellent laboratory in which technologies, methodologies, internal programs, human-resource initiatives, suppliers and subsuppliers, university resources, and engineering and spinoff companies were developed to achieve and sustain the high production of these fields. 1971 to 1974: First Exploratory Wells Drilled and First Discoveries. The first exploratory well in the Campos Basin, named 1-RJS-1, was drilled in 1971 with a jackup-type rig at a WD of 49 m, which resulted in a dry well with no indications of hydrocarbons. In the following years, additional exploratory wells were drilled in WDs of greater than 60 m. The first indications of hydrocarbons were noticed in 1973 in another exploratory well, although it had no production potential. In fact, seven dry wells were drilled since the beginning of the well-exploration campaign.

Registration of High‐Yielding Exotically Derived Soybean Germplasm Line LG03‐4561‐14

The release of soybean [Glycine max (L.) Merr.] germplasm line LG03‐4561‐14 (Reg. No. GP‐434, PI 689003) is part of an effort to expand the current narrow genetic base of the US soybean breeding pool by incorporating new genetic diversity from exotic sources. LG03‐4561‐14 is a high‐yielding, conventional, late maturity group III germplasm line that brings in new genetic diversity for potentially increasing seed yield. LG03‐4561‐14 was developed and released by the USDA‐ARS, Stoneville, MS. LG03‐4561‐14 was derived from FC 04007B, PI 68508, and PI 445837 and has 25% exotic parentage. In 4 yr of testing in the Southern Uniform Tests, LG03‐4561‐14 (3168 kg ha−1) was equivalent in yield to the high‐yielding commercial cultivars ‘AG3803’ (3190 kg ha−1) and ‘AG3934’ (3214 kg ha−1). In the early production system of the mid‐southern United States, the seed yields across 5 yr at Stoneville of LG03‐4561‐14 (4242 kg ha−1), AG3803 (4659 kg ha−1), and AG3934 (4788 kg ha−1) were not significantly different. LG03‐4561‐14 is resistant to southern stem canker and frogeye leaf spot but susceptible to charcoal rot and Phomopsis seed decay. LG03‐4561‐14 will be a valuable source of new genetic diversity for soybean breeding programs in both the public and private sectors.

Bones and Seeds: An Integrated Approach to Understanding the Spread of Farming across the Western Balkans

ABSTRACT Animals and plants, both farmed and hunted/collected, were an integrated part of the Neolithic food economy. When jointly analysed these can provide a holistic view of early food production systems which goes beyond individual descriptions of herd management and crop cultivation. Exhaustive surveys of both Neolithic zooarchaeological and archaeobotanical data were collected from the western Balkans and neighbouring regions (Croatia, Bosnia and Herzegovina, Serbia, southern Hungary, western Romania and eastern Italy). Here we combine both sets of data to explore the Neolithic food economy along the maritime and inland streams of Neolithisation. We demonstrate that, notwithstanding significant limitations, it is possible to compare and combine the datasets and present an integrated approach to the spread and development of farming within the western Balkans. Our research also evinces diachronic and spatial differences within the exploitation of domesticated and wild species, and the factors that may have influenced such practices.

Evaluating Soybean Cultivars for Low- and High-Temperature Tolerance During the Seedling Growth Stage

Soybean (Glycine max L.) seedlings may be exposed to low or high temperatures under early or conventional soybean production systems practiced in the US Midsouth. However, a wide range of soybean cultivars commonly grown in the region may inherit diverse tolerance to degrees of temperatures. Therefore, a study was conducted in a controlled-environment facility to quantify 64 soybean cultivars from Maturity Group III to V, to low (LT; 20/12 °C), optimum (OT; 30/22 °C), and high (HT; 40/32 °C) temperature treatments during the seedling growth stage. Several shoot, root, and physiological parameters were assessed at 20 days after sowing. The study found a significant decline in the measured root, shoot, and physiological parameters at both low and high temperatures, except for root average diameter (RAD) and lateral root numbers under LT effects. Under HT, shoot growth was significantly increased, however, root growth showed a significant reduction. Maturity group (MG) III had significantly lower values for the measured root, shoot, and physiological traits across temperature treatments when compared with MG IV and V. Cultivar variability existed and reflected considerably through positive or negative responses in growth to LT and HT. Cumulative stress response indices and principal component analysis were used to identify cultivar-specific tolerance to temperatures. Based on the analysis, cultivars CZ 5225 LL and GS47R216 were identified as most sensitive and tolerant to LT, while, cultivars 45A-46 and 5115LL identified as most tolerant and sensitive to HT, respectively. The information on cultivar-specific tolerance to low or high temperatures obtained in this study would help in cultivar selection to minimize stand loss in present production areas.

Food between the country and the city: The politics of food production at Shimao and Zhaimaoliang in the Ordos Region, northern China

The archaeology of early China has commonly been critically explored through the study of specialization, particularly in regards to craft production and secondary product exploitation in the late Neolithic and early Bronze Age periods. It is argued that if we are to gain a clearer understanding of the important changes which characterize the development of urbanization in early China, we must also study and compare food remains in order to understand early food production systems. Here, we use faunal remains to compare food production and animal exploitation strategies between the late Neolithic to early Bronze Age urban site of Shimao, and a contemporaneous small rural village, Zhaimaoliang. A detailed quantitative analysis of taxonomic compositions, mortality profiles, and body part distributions are used to suggest that residents at both sites equally produced animals at the household level. Results demonstrate that residents at both sites exploited a limited range of domestic species. Furthermore, survivorship data indicate that at both sites the main domestic animals (pigs, caprine, and cattle) were primarily exploited for primary products such as meat, and a wide diversity of age groups were represented including juvenile and animals that survived into full adulthood.

Comparison of Early and Conventional Soybean Production Systems for Yield and other Agronomic Traits

The early soybean production system (ESPS) was reported to be beneficial for yield compared to the conventional soybean production system (CSPS) and is widely used in the Southern USA. The objective of this study was to compare yield, yield components, root traits, and shoot traits in ESPS (April planting) and CSPS (June planting) in NC Sandhills using a recombinant inbred line (RIL) population, ‘Hartwig’ by ‘Flyer’ (n=92). The population was grown in Spring Lake, NC in 2008 at a density of 16 seeds m-2. The traits measured were days to germination, days to flowering, plant height, seed weight, seed number, pod number, harvest index, root fresh weight, root dry weight, shoot fresh weight, shoot dry weight, maximum root length, and lateral root number. The survival rate ranged from 83.7 to 90.22% for ESPS; however, it was 21.74% for CSPS. Significant differences were observed for almost all traits measured in ESPS (April) compared to CSPS (June) apart from fresh root weight and lateral root number. An average increase in flowering time of 9 days was observed in CSPS compared to ESPS. On the other hand, several traits showed a significant mean decrease in CSPS compared to ESPS as plant height by 41.96%, seed weight by 74.7%, harvest index by 73.3%, pod number by 65.2%, and seed number by 64.9%. The means for root fresh weight, root dry weight, shoot fresh weight, shoot dry weight, maximum root length, and lateral root numbers are shown in Table 2 for both ESPS and CSPS. The results indicated an average decrease of 40.4% in root fresh weight, of 70.2% in root dry weight, of 68.1% in shoot fresh weight, of 80.1% in shoot dry weight, and of 83.3% in maximum root length in CSPS compared to ESPS. However, lateral root numbers increased by an average of 12.7% in CSPS compared to ESPS. Therefore, CSPS may not be appropriate for soybean at least in NC Sandhills.

Macro-Nutrient Concentration and Content of Irrigated Soybean Grown in the Early Production System of the Midsouth

ABSTRACTMacro-nutrients in soybean (Glycine max L. Merr.) have not been extensively researched recently. Concentrations and contents of nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur (N, P, K, Ca, Mg, and S) were determined for three irrigated cultivars grown using the early soybean production system (ESPS) on two soils (a sandy loam and a clay) in the Mississippi Delta during 2011 and 2012. Data were collected at growth stages V3, R2, R4, R6, and R8. No change in macro-nutrients due to soil type or years occurred and modern cultivars were similar to data collected >50 years ago. Mean seed yield of 3328 kg ha−1 removed 194.7 kg N ha−1, 16.5 kg P ha−1, 86.0 kg K ha−1, 17.5 kg Ca ha−1, 9.0 kg Mg ha−1, and 10.4 kg S ha−1. Increased yields over the decades are likely due to changed plant architecture and/or pests resistance, improved cultural practices, chemical weed control, and increased levels of atmospheric carbon dioxide (CO2). Yield improvements by genetically manipulating nutrient uptake appear to be unlikely.

Progressive damage modeling of spiral and ring composite structures for offloading hoses

Offloading hoses are used in several production and storage systems, such as Early Production System (EPS) and Catenary Anchor Leg Mooring (CALM). If the hose is bent until collapse (kink) of the circular section, the steel spiral within the hose undergoes plastic deformation and obstructs the section. Carbon fiber composites have been used for producing a variety of structures and recent improvement in processing has allowed the obtaining of curved profiles for selected applications. In this work, composite spirals/ring manufactured by curved pultrusion and filament winding for marine offloading hoses have been studied and a progressive damage model was used to simulate their behavior. The composites are comprised of epoxy or poly(p-phenylene sulfide) (PPS) matrix reinforced by unidirectional carbon fibers. A finite element model of the central section of the complex hose was built to compare its ultimate load crushing when composite and steel spirals and rings are used. The damage model was implemented as UMAT (User Material subroutine) linked to numerical software. The predictions of ultimate crushing load showed good agreement with the experimental results, and a maximum deviation of 2.3% was found.

Early Bronze Age copper production systems in the northern Arabah Valley: New insights from archaeomagnetic study of slag deposits in Jordan and Israel

This paper presents results of an archaeomagnetic study of slag from four Early Bronze (EB) Age copper production sites in the Faynan Copper Ore District and the northern Arabah Valley (modern Israel and Jordan). The results provide age constraints for metallurgical activities at these sites. Together with previously published data, they indicate copper production around ca. 2900 cal. BCE (EB II-III transition) and between ca. 2600-1950 cal. BCE, spanning the later part of the EB III and the entire EB IV period. These data strongly suggest a direct link between Faynan and the Old Kingdom of Egypt, which is reflected in the most significant phase of copper production and trade in the northern Arabah prior to the Iron Age, and in a settlement wave in the Negev Highlands. In addition, the results indicate that during the late EB II copper was smelted up to 40 km away from the mines. This is evident at the unique cultic site of Ashalim, located on the main road between Faynan, southeast of the Dead Sea, and the settled areas in the core of Canaan.

Documenting Differences between Early Stone Age Flake Production Systems: An Experimental Model and Archaeological Verification.

This study investigates morphological differences between flakes produced via “core and flake” technologies and those resulting from bifacial shaping strategies. We investigate systematic variation between two technological groups of flakes using experimentally produced assemblages, and then apply the experimental model to the Cutting 10 Mid -Pleistocene archaeological collection from Elandsfontein, South Africa. We argue that a specific set of independent variables—and their interactions—including external platform angle, platform depth, measures of thickness variance and flake curvature should distinguish between these two technological groups. The role of these variables in technological group separation was further investigated using the Generalized Linear Model as well as Linear Discriminant Analysis. The Discriminant model was used to classify archaeological flakes from the Cutting 10 locality in terms of their probability of association, within either experimentally developed technological group. The results indicate that the selected independent variables play a central role in separating core and flake from bifacial technologies. Thickness evenness and curvature had the greatest effect sizes in both the Generalized Linear and Discriminant models. Interestingly the interaction between thickness evenness and platform depth was significant and played an important role in influencing technological group membership. The identified interaction emphasizes the complexity in attempting to distinguish flake production strategies based on flake morphological attributes. The results of the discriminant function analysis demonstrate that the majority of flakes at the Cutting 10 locality were not associated with the production of the numerous Large Cutting Tools found at the site, which corresponds with previous suggestions regarding technological behaviors reflected in this assemblage.

Limited-Entry Liner With Retrievable Ball-Drop Diversion System in a Deepwater Brazil Field

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper IPTC 18113, “Unconventionals Meet Deep Water: Lower-Completion Limited- Entry Liner With Retrievable Ball-Drop Diversion System Applied in a Deepwater Brazil Carbonate Field,” by M.A. Fowler, R.D. Gdanski, P. Campbell, W. Bode, J.M. Baima, and S. Hensgens, Shell, prepared for the 2014 International Petroleum Technology Conference, Kuala Lumpur, 10–12 December. The paper has not been peer reviewed. This paper describes the design, testing, and execution of a unique deepwater completion system that adapts a known multistage ball-drop system used in onshore unconventional reservoirs—for example, in the US and Canada—to a known horizontal openhole sand-control system to matrix acidize a 2000-m horizontal open hole effectively through a limited-entry liner with reservoir segmentation. The system uses a retrievable ball-drop diversion system (RBDDS) consisting of multistage fracture sleeves run on wash pipe. Introduction Low-permeability deepwater carbonate reservoirs have presented many challenges for economical production. The wells typically require extensive reservoir contact that must be stimulated in order to achieve an acceptable productivity index. Field A of the Albian carbonate in the Campos basin offshore Brazil falls into this challenging category (Fig. 1). The field is mature, having been on production since the early 1990s from various Eocene sandstone reservoirs. Initially, the field was produced under depletion by an early production system up to the late 1990s. Then, in the early 2000s, a field redevelopment was performed and production was restarted in 2003 to a floating production, storage, and offloading vessel (FPSO), now with water-injection support. The Quissama member of the Al bian Macae formation in the Campos basin underlies the existing Eocene reservoirs but has not been produced to date. To help extend field life and to evaluate the production potential of this formation, a development/appraisal well was planned to be completed and hooked up to the FPSO and the subsea infrastructure. The Albian carbonate below Fields A and B lies in 769 m of water and exhibits low permeability. For a detailed discussion of the well’s functional specifications and requirements, please see the complete paper.

Screening Corn Hybrids for Cold Tolerance using Morphological Traits for Early‐Season Seeding

ABSTRACTEarly planting of corn (Zea mays L.) is a strategy to avoid excessive heat and drought that often negatively influence grain production during its reproductive phase. An experiment was conducted by imposing very low (day/night, 21/13°C), low (25/17°C), and optimum (29/21°C) temperatures during seed germination and seedling growth stages under optimum moisture and nutrient conditions. Above‐ and belowground growth parameters were assessed at 18 d after seeding. Several root morphological traits were assessed using the WinRHIZO root image analysis system. Corn hybrids varied significantly for many traits measured, particularly plant component weights and root morphological parameters. Principal component analysis (PCA) and total low‐temperature response index (TLTRI) methods were used to categorize corn hybrid tolerance to low temperature and to group corn hybrids as cold tolerant, moderately cold tolerant, moderately cold sensitive, and cold sensitive. Total leaf and root weights and cumulative root length and length per unit volume were the most important morphological traits in describing hybrid tolerance to cold temperature. Based on the TLTRI method, relative scores were provided for each hybrid, which ranged from 22.45 to 29.52 among the hybrids. The hybrids CR8410VT3P, D57VP51, and R22BHR43 were classified as cold sensitive and AR1262, DKC6697, DKC6804, and M2V707 as cold tolerant based on PCA and TLTRI techniques. Based on the relative scores assigned in this study, corn producers could select hybrids to maximize corn production in an early planting production system.

Notes on Contributors

Notes on Contributors

A comparison of coupled and uncoupled dynamic analysis for the flexible riser in shallow water

Flexible risers have been used extensively in recent years for floating and early production systems. Such risers offer the advantage of having inherent heave compliance in their catenary thereby greatly reducing the complexity of the riser-to-rig and riser-to subsea interfaces. Another advantage with flexible risers is their greater reliability. Concerns about fatigue life, gas permeation and pigging of lines have been overcome by extensive experience with these risers in production applications. In this paper, flexible riser analysis results were compared through coupled and uncoupled dynamic analyses methods. A time domain coupled analysis capability has been developed to model the dynamic responses of an integrated floating system incorporating the interactions between vessel, moorings and risers in a marine environment. For this study, SPM (Single Point Mooring) system for an FSU in shallow water was considered. This optimization model was integrated with a time-domain global motion analysis to assess both stability and design constraints of the flexible riser system

Developing selection criteria based on an ontogenetic path analysis approach to improve grain yield in barley.

We used correlation and path coefficient analysis based on an ontogenetic approach to develop selection criteria in barley (Hordeum vulgare L.) for an early production system in Ethiopia. A total of 100 genotypes using 10x10-simple lattices with two replications were used to perform the experiment at Ambo and Asasa. The combined analysis of the measured traits showed significant differences among genotypes for all traits. A positive correlation was observed between grain yield and spike/m2, kernel number/spike, and 1000-kernel weight. The path analysis showed that spike/m2, 1000-kernel weight, and kernel number per spike had significant positive direct effects on grain yield, which shows that these traits can be used as selection criteria to improve grain yield. The significant positive correlation of spike/ m2, 1000-kernel weight, and grain-filling period and the positive direct effect on grain yield indicated the potential of these traits as indirect selection criteria to improve grain yield in the early production system in Ethiopia. This study also showed that the path coefficient analysis based on an ontogenetic model was efficient and produced results that can be interpreted clearly.