Soybean Domestication Research Articles

Does Soybean in Indonesia Still Competitive?: A Policy Analysis Matrix Approach

The low productivity of soybeans in Indonesia is one of the reasons why domestic production cannot meet market demand. In addition to suboptimal and contradictory government policies, they contribute to domestic soybean competitiveness against imported soybeans. The purpose of this study is to analyze the economic and financial profitability of farming, analyze the competitiveness status of soybeans, analyze the impact of government policies on soybean competitiveness, and analyze the sensitivity of domestic soybean competitiveness. This study applies the Policy Analysis Matrix (PAM). The results of this analysis are used to observe two basic indicators to measure competitiveness and assess the role of government policies. This research uses a case study of soybean farmers in the Jember Regency area. The analysis results show that the soybean farming business in Jember Regency is capable of generating economic profits. Soybean farming in Jember is capable of producing comparative and competitive advantages. Furthermore, the policy analysis reveals that the impact of the soybean policy on farming in the region is not yet optimal. Therefore, new governance policies are needed. Parameter analysis in the PAM analysis indicates that price and productivity variables have a potential role in increasing production and domestic soybean competitiveness.

Progress and future impacts on genomic dissection of soybean domestication and improvement

Soybean (Glycine max [L.] Merr.) was domesticated from the wild annual progenitor Glycine soja (Sieb. & Zucc.) in the temperate zone of China. Through domestication and improvement, soybean agronomic traits and adaptability have been significantly altered. In this review, we discuss the ways in which genetic changes were selected in soybean to enable adaptation to diverse environmental conditions. Challenges and strategies are discussed for breeding new elite varieties from existing elite varieties. Finally, we propose a strategy to break the current genetic bottleneck in soybean breeding: de novo domestication, which utilizes the excellent genetic resources available in wild soybean and provides a feasible strategy for accelerating the soybean improvement process. Overall, this review serves as a guide to understand the genetic factors that have driven soybean domestication and improvement over thousands of years, promoting future generation of soybean cultivars that are optimized for high yield under stressful environmental conditions.

Impact of a large-scale replacement of maize by soybean on water deficit in Europe

The EU imports large quantities of soybeans, mainly for livestock feed. However, there is a trend to increase domestic soybean production and reduce imports. In this study, we investigate the potential impact of an increased EU soybean cultivation on evapotranspiration (ET), water deficit, and irrigation needs. We focus on the consequences of replacing maize with soybeans, as both crops have similar cropping periods and high water demands. We implement a simple, well established crop water model that estimates crop water deficit (ETd) as the difference between simulated potential (ETc) and actual (ETa) ET. We apply this model over the EU from 2001 to 2020, using data on daily reference ET and precipitation, soil hydrological properties and three different crop calendars. Results indicate that a maize-to-soybean conversion would result in an average ETd increase of 49.0 ± 22.1 mm season−1 across the EU. In the four countries of France, Italy, Hungary and Romania, where most of the additional soybean production would be allocated, crop water deficits would increase on average by 21–34 % compared to that of maize, following an increased ETc and/or decreased ETa. However, the decrease in ETa is largely due to an assumed shorter root depth for soybean, while recent empirical results suggest that both crops may actually have comparable root depths. Using the same root depth for maize and soybean, the simulated average increase in ETd amounts to only 28.2 ± 18.3 mm season−1. Our results are sensitive to the choice of crop calendar, with reduced ETd for later sowing dates.

Soybean type-B response regulator GmRR1 mediates phosphorus uptake and yield by modifying root architecture.

Phosphorus (P) plays a pivotal role in plant growth and development. Low P stress can greatly hamper plant growth. Here, we identified a QTL (named QPH-9-1), which is associated with P efficiency across multiple environments through linkage analysis and genome-wide association study. Furthermore, we successfully cloned the underlying soybean (Glycine max) gene GmRR1 (a soybean type-B Response Regulator 1) that encodes a type-B response regulator protein. Knockout of GmRR1 resulted in a substantial increase in plant height, biomass, P uptake efficiency, and yield-related traits due to the modification of root structure. In contrast, overexpression of GmRR1 in plants resulted in a decrease in these phenotypes. Further analysis revealed that knockout of GmRR1 substantially increased the levels of auxin and ethylene in roots, thereby promoting root hair formation and growth by promoting the formation of root hair primordium and lengthening the root apical meristem. Yeast two-hybrid, bimolecular fluorescence complementation, and dual-luciferase assays demonstrated an interaction between GmRR1 and Histidine-containing Phosphotransmitter protein 1. Expression analysis suggested that these proteins coparticipated in response to low P stress. Analysis of genomic sequences showed that GmRR1 underwent a selection during soybean domestication. Taken together, this study provides further insights into how plants respond to low P stress by modifying root architecture through phytohormone pathways.

UV-B irradiation-activated E3 ligase GmILPA1 modulates gibberellin catabolism to increase plant height in soybean

Plant height is a key agronomic trait that affects yield and is controlled by both phytohormone gibberellin (GA) and ultraviolet-B (UV-B) irradiation. However, whether and how plant height is modulated by UV-B-mediated changes in GA metabolism are not well understood. It has not been reported that the E3 ubiquitin ligase Anaphase Promoting Complex/Cyclosome (APC/C) is involved in the regulation of plant growth in response to environmental factors. We perform a forward genetic screen in soybean and find that a mutation in Glycine max Increased Leaf Petiole Angle1 (GmILPA1), encoding a subunit of the APC/C, lead to dwarfism under UV-B irradiation. UV-B promotes the accumulation of GmILPA1, which ubiquitinate the GA catabolic enzyme GA2 OXIDASE-like (GmGA2ox-like), resulting in its degradation in a UV-B-dependent manner. Another E3 ligase, GmUBL1, also ubiquitinate GmGA2ox-like and enhance the GmILPA1-mediated degradation of GmGA2ox-like, which suggest that GmILPA1-GmGA2ox-like module counteract the UV-B-mediated reduction of bioactive GAs. We also determine that GmILPA1 is a target of selection during soybean domestication and breeding. The deletion (Indel-665) in the promoter might facilitate the adaptation of soybean to high UV-B irradiation. This study indicates that an evolutionary GmILPA1 variant has the capability to develop ideal plant architecture with soybean cultivars.

QTL Mapping of Soybean (Glycine max) Vine Growth Habit Trait.

The vine growth habit (VGH) is a notable property of wild soybean plants that also holds a high degree of importance in domestication as it can preclude using these wild cultivars for breeding and improving domesticated soybeans. Here, a bulked segregant analysis (BSA) approach was employed to study the genetic etiology of the VGH in soybean plants by integrating linkage mapping and population sequencing approaches. To develop a recombinant inbred line (RIL) population, the cultivated Zhongdou41 (ZD41) soybean cultivar was bred with ZYD02787, a wild soybean accession. The VGH status of each line in the resultant population was assessed, ultimately leading to the identification of six and nine QTLs from the BSA sequencing of the F4 population and F6-F8 population sequence mapping, respectively. One QTL shared across these analyzed generations was detected on chromosome 19. Three other QTLs detected by BSA-seq were validated and localized to the 90.93 kb, 2.9 Mb, and 602.08 kb regions of chromosomes 6 and 13, harboring 14, 53, and 4 genes, respectively. Three consistent VGH-related QTLs located on chromosomes 2 and 19 were detected in a minimum of three environments, while an additional six loci on chromosomes 2, 10, 13, and 18 were detected in at least two environments via ICIM mapping. Of all the detected loci, five had been reported previously whereas seven represent novel QTLs. Together, these data offer new insights into the genetic basis of the VGH in soybean plants, providing a rational basis to inform the use of wild accessions in future breeding efforts.

How climate change and international trade will shape the future global soybean security pattern

Soybean planting is highly concentrated and sensitive to climate change, which makes global soybean security vulnerable to production fluctuations in the main producing countries. As an important trade commodity, the impacts of climate change on soybean production in the main producing countries can ripple globally through international trade. However, little is known about the spatial distribution of soybean security under future climate at the global scale. This study couples an ensemble of multi-crop models and a global economic model (GTAP, Global Trade Analysis Project) to evaluate variations in soybean yield of the top ten soybean-producing countries in the 2050s (2046–2055) and the consequent impacts on global soybean supply and price under a range of future climate scenarios. Our results show that (1) The top ten soybean-producing countries, accounting for nearly 97% of global soybean production, suffer an average soybean yield reduction of 0.82% (specific to each country: −5.81%∼7.05%), 0.43% (−23.5%∼11.72%) and 5.22% (−17.88%∼18.73%) under Representative Concentration Pathway (RCP) 2.6, RCP4.5 and RCP 8.5, respectively, when considering the fertilization effect of CO2. A substantial soybean yield loss of 19.51% (−28.86%∼2.97%) is projected under RCP8.5 without accounting for the CO2 fertilization effect. (2) Climate-induced yield reduction leads to insufficient soybean supply and higher price worldwide through the transmission of international trade, with the largest supply decline of 14.20% in Bolivia and the largest price increase of 91.19% in India. Regionally, soybean net-importing countries are more vulnerable because of the ripple effect of the soybean supply chain. For example, despite a simulated increase in soybean yield of 2.97%–18.73%, China's soybean supply will decline by 0.61%–2.27% due to import shortages from the United States and Brazil where severe soybean yield losses are witnessed. (3) Liberal trade does dampen the negative impact of climate change on global soybean supply and price by reducing trade costs and facilitating trade flows, but in soybean export-oriented regions, trade liberalization can result in increased exports at the expense of domestic soybean supply (e.g., Canada and Russia). Our findings highlight the necessity of developing a liberal trade policy that benefits all regions of the world and improving domestic soybean productivity to adapt to climate change.

WGCNA and transcriptome profiling reveal hub genes for key development stage seed size/oil content between wild and cultivated soybean

BackgroundSoybean is one of the most important oil crops in the world. The domestication of wild soybean has resulted in significant changes in the seed oil content and seed size of cultivated soybeans. To better understand the molecular mechanisms of seed formation and oil content accumulation, WDD01514 (E1), ZYD00463 (E2), and two extreme progenies (E23 and E171) derived from RILs were used for weighted gene coexpression network analysis (WGCNA) combined with transcriptome analysis.ResultsIn this study, both seed weight and oil content in E1 and E171 were significantly higher than those in E2 and E23, and 20 DAF and 30 DAF may be key stages of soybean seed oil content accumulation and weight increase. Pathways such as “Photosynthesis”, “Carbon metabolism”, and “Fatty acid metabolism”, were involved in oil content accumulation and grain formation between wild and cultivated soybeans at 20 and 30 DAF according to RNA-seq analysis. A total of 121 oil content accumulation and 189 seed formation candidate genes were screened from differentially expressed genes. WGCNA identified six modules related to seed oil content and seed weight, and 76 candidate genes were screened from modules and network. Among them, 16 genes were used for qRT-PCR and tissue specific expression pattern analysis, and their expression-levels in 33-wild and 23-cultivated soybean varieties were subjected to correlation analysis; some key genes were verified as likely to be involved in oil content accumulation and grain formation.ConclusionsOverall, these results contribute to an understanding of seed lipid metabolism and seed size during seed development, and identify potential functional genes for improving soybean yield and seed oil quantity.

Analysis of Indonesia's Soybean Competitiveness

The current national soybean demand is reaching 4 million tons, but domestic production only meets 1/16 of that demand. The increasing domestic soybean demand, coupled with a decreasing national soybean production each year, has led to Indonesia's dependence on imports. There are numerous issues with the soybean commodity that have resulted in the weak competitiveness of Indonesian soybeans in the international market. However, several soybean production centers show that soybean cultivation is still viable for development. This research aims to analyze the competitiveness level of Indonesian soybean commodities. Revealed Comparative Advantage (RCA) analysis is utilized to assess the competitiveness level of Indonesian soybeans in the international market. The research findings that The RCA value is less than 1, indicating that Indonesian soybeans lack competitiveness or have weak competitiveness.

Exploring seed and meal composition and protein solubility in soybean genotypes from different domestication periods

AbstractTraditionally, commercial soybean breeding has focused on increasing seed yield by crossing elite cultivars and limiting the genetic diversity within commercial germplasm. Wild and ancestral soybean genotypes have higher seed protein concentrations than commercial ones. Different seed protein concentrations and compositions result in diverse functional properties of soybean meal, in particular solubility is important for beverages and protein isolates production. The objectives of our study were (i) to characterize seed protein concentration and composition in genotypes from different soybean domestication periods (types) and (ii) to evaluate the protein concentration and solubility profiles of the defatted meals obtained from these genotypes. Variation within seed and meal protein concentration, composition, and solubility was evident along the domestication process. Wild relative (G. soja) and Elite genotypes had the maximum and minimum seed protein concentrations, respectively (42.9 and 36.3 g 100 g−1). Soybean meal protein concentrations were 55.1, 47.7, 48.4 and 44.1 g 100 g−1 for Wild relative (G. soja), Asian landraces, North American (Nam) ancestors and Elite, respectively. Ample genotypic variation was observed for β‐conglycinin components, such as for β, α, and α′ subunits and for total glycinin and its components. Asian landraces had the highest protein solubility. Wild and ancestral germplasm are a reservoir of useful traits to improve soybean seed quality. This study opens the gates to the introduction of ancestral germplasm to breeding programs focused on protein quality and functionality.

PENGARUH PEMBERIAN KALIUM TERHADAP FISIOLOGIS DAN MORFOLOGIS KEDELAI PADA CEKAMAN KEKERINGAN

Domestic soybean production is weakened by the problem of drought stress that affects all aspects of plant growth and metabolism, while an alternative that can be used is the use of potassium. Potassium is believed to have an important role in increasing plant tolerance to drought. This study aims to examine the effect of potassium application on the physiological and morphological of drought-stressed soybean. The research was conducted in a plastic house in Aras Kabu Village, Beringin Subdistrict, Deli Serdang Regency, North Sumatra using a group randomized design with two factors and three replications. The first factor was soil moisture condition consisting of 80% KL (field capacity) and 40% KL. The second factor was potassium fertilizer application of 100 kg/ha, 200 kg/ha, 300 kg/ha, and no potassium fertilizer. The observed variables were total sugar and leaf area. The results showed that the use of potassium can increase the value of total sugar and leaf area of drought-stressed soybean. Application of K dose of 100 kg/ha (0.5 g/polybag) is the most appropriate to encourage physiological and morphological drought stressed soybean plants.

The domestication-associated L1 gene encodes a eucomic acid synthase pleiotropically modulating pod pigmentation and shattering in soybean

Pod coloration is a domestication-related trait in soybean, with modern cultivars typically displaying brown or tan pods, while their wild relative, Glycine soja, possesses black pods. However, the factors regulating this color variation remain unknown. In this study, we cloned and characterized L1, the classical locus responsible for black pods in soybean. By using map-based cloning and genetic analyses, we identified the causal gene of L1 and revealed that it encodes a hydroxymethylglutaryl-coenzyme A (CoA) lyase-like (HMGL-like) domain protein. Biochemical assays showed that L1 functions as a eucomic acid synthase and facilitates the synthesis of eucomic acid and piscidic acid, both of which contribute to coloration of pods and seed coats in soybean. Interestingly, we found that L1 plants are more prone to pod shattering under light exposure than l1 null mutants because dark pigmentation increases photothermal efficiency. Hence, pleiotropic effects of L1 on pod color and shattering, as well as seed pigmentation, likely contributed to the preference for l1 alleles during soybean domestication and improvement. Collectively, our study provides new insights into the mechanism of pod coloration and identifies a new target for future de novo domestication of legume crops.

Parental choice and seed size impact the uprightness of progeny from interspecific Glycine hybridizations

AbstractThe narrow genetic base of the US soybean (Glycine max [L.] Merr.) crop makes it vulnerable to emerging abiotic and biotic stress challenges, and limits resiliency of the soybean crop to meet changes in consumer demand for improved seed composition and agronomic performance. The United States Department of Agriculture Glycine soja (Siebold & Zucc.) germplasm collection provides a valuable genetic resource to meet these challenges. Glycine soja is more genetically diverse than domesticated soybean. Even though wild soybean hybridizes freely with G. max, breeding efforts with wild soybean have not been widely employed because the interspecific progeny inherits undesirable traits from the wild parent. Particularly, these progenies inherit a vine‐like architecture that prevents machine harvest. We assessed the potential for improving recovery of agronomically valuable progeny from interspecific crosses in three experiments using 11 interspecific populations. We found that optimal choice of either parent could triple the frequency of recovery of desirable progeny. Selection for large F3 seed size was positively correlated with upright growth habit/plant architecture in five of 11 populations and could triple the recovery of desirable plants. Marker analysis of parents and progeny indicated selection for larger seed size caused minimal selection against the genome of the wild parent. Most genetic markers specific to a wild parent could be recovered in the aggregate of 8–10 upright interspecific progenies, identified via post selection marker analysis. We concluded that choice of parent and selection for larger seed can maximize recovery of the wild genome in machine harvestable progenies.

GmMFT: a potential step forward in soybean breeding for high oil and yield.

This article is a Commentary on Cai et al. (2023), 239: 905–919.

GmJAZ3 interacts with GmRR18a and GmMYC2a to regulate seed traits in soybean.

Seed weight is usually associated with seed size and is one of the important agronomic traits that determine yield. Understanding of seed weight control is limited, especially in soybean plants. Here we show that Glycine max JASMONATE-ZIM DOMAIN 3 (GmJAZ3), a gene identified through gene co-expression network analysis, regulates seed-related traits in soybean. Overexpression of GmJAZ3 promotes seed size/weight and other organ sizes in stable transgenic soybean plants likely by increasing cell proliferation. GmJAZ3 interacted with both G. max RESPONSE REGULATOR 18a (GmRR18a) and GmMYC2a to inhibit their transcriptional activation of cytokinin oxidase gene G. max CYTOKININ OXIDASE 3-4 (GmCKX3-4), which usually affects seed traits. Meanwhile, the GmRR18a binds to the promoter of GmMYC2a and activates GmMYC2a gene expression. In GmJAZ3-overexpressing soybean seeds, the protein contents were increased while the fatty acid contents were reduced compared to those in the control seeds, indicating that the GmJAZ3 affects seed size/weight and compositions. Natural variation in JAZ3 promoter region was further analyzed and Hap3 promoter correlates with higher promoter activity, higher gene expression and higher seed weight. The Hap3 promoter may be selected and fixed during soybean domestication. JAZ3 orthologs from other plants/crops may also control seed size and weight. Taken together, our study reveals a novel molecular module GmJAZ3-GmRR18a/GmMYC2a-GmCKXs for seed size and weight control, providing promising targets during soybean molecular breeding for better seed traits.

Differential SW16.1 allelic effects and genetic backgrounds contributed to increased seed weight after soybean domestication.

Although seed weight has increased following domestication from wild soybean (Glycine soja) to cultivated soybean (Glycine max), the genetic basis underlying this change is unclear. Using mapping populations derived from chromosome segment substitution lines of wild soybean, we identified SW16.1 as the causative gene underlying a major quantitative trait locus controlling seed weight. SW16.1 encodes a nucleus-localized LIM domain-containing protein. Importantly, the GsSW16.1 allele from wild soybean accession N24852 had a negative effect on seed weight, whereas the GmSW16.1 allele from cultivar NN1138-2 had a positive effect. Gene expression network analysis, reverse-transcription quantitative polymerase chain reaction, and promoter-luciferase reporter transient expression assays suggested that SW16.1 regulates the transcription of MT4, a positive regulator of seed weight. The natural variations in SW16.1 and other known seed weight genes were analyzed in soybean germplasm. The SW16.1 polymorphism was associated with seed weight in 247 soybean accessions, showing much higher frequency of positive-effect alleles in cultivated soybean than in wild soybean. Interestingly, gene allele matrix analysis of the known seed weight genes revealed that G. max has lost 38.5% of the G. soja alleles and that most of the lost alleles had negative effects on seed weight. Our results suggest that eliminating negative alleles from G. soja led to a higher frequency of positive alleles and changed genetic backgrounds in G. max, which contributed to larger seeds in cultivated soybean after domestication from wild soybean. Our findings provide new insights regarding soybean domestication and should assist current soybean breeding programs.

Major genetic locus with pleiotropismdetermined seed-related traits in cultivated and wild soybeans.

Here, a novel pleiotropic QTL qSS14 simultaneously regulating four seed size traits and two consistently detected QTLs qSW17 and qSLW02 were identified across multiple years. Seed-related traits were the key agronomic traits that have been artificially selected during the domestication of wild soybean. Identifying the genetic loci and genes that regulate seed size could clarify the genetic variations in seed-related traits and provide novel insights into high-yield soybean breeding. In this study, we used a high-density genetic map constructed by F10 RIL populations from a cross between Glycine max and Glycine soja to detect additive QTLs for seven seed-related traits over the last three years. As a result, we identified one novel pleiotropic QTL, qSS14, that simultaneously controlled four seed size traits (100-seed weight, seed length, seed width, and seed thickness) and two consistently detected QTLs, qSW17, and qSLW02, in multiple years of phenotypic data. Furthermore, we predicted two, two and three candidate genes within these three critical loci based on the parental resequencing data and gene function annotations. And the relative expression of four candidate genes GLYMA_14G155100, GLYMA_17G061000, GLYMA_02G273100, and GLYMA_02G273300 showed significant differences among parents and the extreme materials through qRT-PCR analysis. These findings could facilitate the determination of beneficial genes in wild soybean and contribute to our understanding of the soybean domestication process.

Genome-wide scan for oil quality reveals a coregulation mechanism of tocopherols and fatty acids in soybean seeds

Tocopherols (vitamin E) play essential roles in human health because of their antioxidant activity, and plant-derived oils are the richest sources of tocopherols in the human diet. Although soybean (Glycine max) is one of the main sources of plant-derived oil and tocopherol in the world, the relationship between tocopherol and oil in soybean seeds remains unclear. Here, we focus on dissecting tocopherol metabolism with the long-term goal of increasing α-tocopherol content and soybean oil quality. We first collected tocopherol and fatty acid profiles in a soybean population (>800 soybean accessions) and found that tocopherol content increased during soybean domestication. A strong positive correlation between tocopherol and oil content was also detected. Five tocopherol pathway–related loci were identified using a metabolite genome-wide association study strategy. Genetic variations in three tocopherol pathway genes were responsible for total tocopherol content and composition in the soybean population through effects on enzyme activity, mainly caused by non-conserved amino acid substitution or changes in gene transcription level. Moreover, the fatty acid regulatory transcription factor GmZF351 directly activated tocopherol pathway gene expression, increasing both fatty acid and tocopherol contents in soybean seeds. Our study reveals the functional differentiation of tocopherol pathway genes in soybean populations and provides a framework for development of new soybean varieties with high α-tocopherol content and oil quality in seeds.

A retrotransposon insertion in the Mao1 promoter results in erect pubescence and higher yield in soybean

Adaptive changes in crops contribute to the diversity of agronomic traits, which directly or indirectly affect yield. The change of pubescence form from appressed to erect is a notable feature during soybean domestication. However, the biological significance and regulatory mechanism underlying this transformation remain largely unknown. Here, we identified a major-effect locus, PUBESCENCE FORM 1 (PF1), the upstream region of Mao1, that regulates pubescence form in soybean. The insertion of a Ty3/Gypsy retrotransposon in PF1 can recruit the transcription factor GAGA-binding protein to a GA-rich region, which up-regulates Mao1 expression, underpinning soybean pubescence evolution. Interestingly, the proportion of improved cultivars with erect pubescence increases gradually with increasing latitude, and erect-pubescence cultivars have a higher yield possibly through a higher photosynthetic rate and photosynthetic stability. These findings open an avenue for molecular breeding through either natural introgression or genome editing toward yield improvement and productivity.

Natural variation of FKF1 controls flowering and adaptation during soybean domestication and improvement.

Soybean (Glycine max) is a major source of protein and edible oil world-wide and is cultivated in a wide range of latitudes. However, it is extremely sensitive to photoperiod, whichinfluences flowering time, maturity, and yield, and severely limits soybean latitude adaptation. In this study, a genome-wide association study (GWAS) identified a novel locus in accessions harboring the E1 allele, called Time of flowering 8 (Tof8), which promotes flowering and enhances adaptation to high latitude in cultivated soybean. Gene functional analyses showed that Tof8 is an ortholog of Arabidopsis FKF1. We identified two FKF1 homologs in the soybean genome. Both FKF1 homologs are genetically dependent on E1 by binding to E1 promoter to activate E1 transcription, thus repressing FLOWERING LOCUS T 2a (FT2a) and FT5a transcription, which modulate flowering and maturity through the E1 pathway. We also demonstrate that the natural allele FKF1bH3 facilitated adaptation of soybean to high-latitude environments and was selected during domestication and improvement, leading to its rapid expansion in cultivated soybean. These findings provide novel insights into the roles of FKF1 in controlling flowering time and maturity in soybean and offer new means to fine-tune adaptation to high latitudes and increase grain yield.