Lucas Borrás

National Scientific and Technical Research Council | conicet · IICAR

Context or problem Maize and sorghum compete for their acreage due to similar agroecological needs and end use. Recent studies discussed the implications of sorghum lower genetic progress when compared to maize, where maize has increased its yield potential and stress tolerance. However, a study that compared their yield genetic progress side-by-si...

Trade‐offs between yield and grain quality for dry milling are common in maize (Zea mays L.), but the magnitude of these correlations can differ depending on the specific quality trait. We aimed to quantify the relationship between yield and grain traits known to affect dry milling, with a focus on describing the genetic control of the traits that...

A key question today is how to harmonize future crop improvement efforts for regenerative cropping systems that can mitigate further environmental degeneration and improve societal adaptation to climate change. Here we show that the U.S. Corn-Belt based maize improvement system has been adapting to the changing climate. Analyses of the longest runn...

Seed storage compound deposition is influenced by both maternal and filial tissues. Within this framework, we analyzed strategies that operate during the development and filling of soybean embryos, using in vitro culture systems combined with metabolomics and proteomics approaches. The carbon:nitrogen ratio (C:N) of the maternal supply and the horm...

As global warming intensifies climatic extremes, the need to understand their effects on farming systems, particularly under rainfed conditions, grows. During the last three decades the Argentine Pampas, a major global grain exporter, hosted an unprecedented expansion of cultivation under unirrigated and undrained conditions. Simultaneously, the ex...

In the last century wheat breeding programs have shown consistent yield increases, often associated with lower grain protein concentrations (GPC). A better understanding of the genetic basis of grain yield and grain protein content can help break the grain yield—GPC negative correlation. We developed a nested association mapping population composin...

Chilling can decrease stomatal sensitivity to abscisic acid (ABA) in some legumes, although hormonal mechanisms involved are unclear. After evaluating leaf gas exchange of 16 European soybean genotypes at 14°C, 6 genotypes representing the range of response were selected. Further experiments combined low (L, 14°C) and high (H, 24°C) temperature exp...

Foliar diseases produce significant maize (Zea maize L.) yield reductions, increasing yield gaps and threatening food security. In the central temperate region of Argentina 50 % of maize cropped is grown under late sowing dates (December), where meteorological conditions are favorable to disease development, such as higher temperatures during initi...

Alternative physiological strategies can increase protein concentration in soybean: (i) more‐than‐proportional increases in seed protein content (mg seed−1) relative to increases in carbohydrate and oil content in large‐seeded genotypes or (ii) more‐than‐proportional reductions in carbohydrate and/or oil content relative to protein content reductio...

Knowledge of maize (Zea mays L.) kernel weight (KW) and kernel number (KN) response to nitrogen (N) fertilization can help understand the physiological basis behind the overall grain yield response to N fertilizer, but such data are rare. To fill this gap, we studied how KN and KW respond to N fertilization. We first analyzed grain yield and its co...

Food grade maize dedicated to dry milling is an ingredient used in everyday foods, such as breakfast cereals, snacks, baked goods, and beer. Argentina has developed a supply chain producing high quality food grade hard endosperm maize for national and international dry milling markets. In modern times, European countries uniquely source their impor...

In many temperate soybean [Glycine max (L.) Merr.] production systems sowing date expands for several months. Early sowing dates commonly show maximum yields, but their consequences for crop N uptake and biological nitrogen fixation (BNF) are unknown. Our objective was to evaluate the role of sowing date, a major management variable defining soybea...

In absence of stress, crop growth depends on the amount of light intercepted by the canopy and the conversion efficiency (radiation use efficiency, RUE). This study tested the hypothesis that long-term genetic gain for grain yield was partly due to improved RUE. The hypothesis was tested using 30 elite maize hybrids commercialized in the US corn be...

Mato Grosso accounts for 25 and 31% of soybean and maize grain production in Brazil, respectively. Despite the importance of this region, there is limited information to optimize fertilization management decisions for these crops. Our objectives were to i) quantify soybean and maize yield response to fertilization, ii) develop prediction algorithms...

Altered stand density affects maize yields by producing changes in both numerical yield components, kernel number per plant (KNP), and kernel weight (KW). Kernel number is determined by the accumulation of ear biomass during the flowering period, whereas KW is determined by the sink potential established during flowering and the capacity of the pla...

Yield genetic gains have been significantly higher for maize (Zea mays L.) than for sorghum (Sorghum bicolor L. Moench). Today there is questioning under which environments sorghum is a better option than maize, since maize has increased its tolerance to water and N limitations. For this we conducted eleven rainfed experiments at different sites ar...

Soybean [Glycine max (L.) Merr.] seed protein concentration has been declining over the past decades with protein values falling below the ∼40% (dry weight base) required for optimal industrial processing. Further refinement of management practices is needed to help maintain concentrations above market standards. The objective of this work was to e...

Maize starch is an important carbohydrate source in human diet, and its digestion contributes to the postprandial blood glucose level. This article describes in vitro starch digestibility and its relation to endosperm hardness and composition in cooked maize flours. Starch digestion and estimated glycemic index (GI) were significantly (p<0.05) lowe...

Kernel hardness is commonly related to total maize (Zea mays L.) carotenoid concentration. Based on the specific interactions between carotenoids and hardness related zeins, we tested the hypothesis that hardness is associated with the ability to store different carotenoids. Carotenoid profiles and flour color were measured in 13 flint and 5 dent t...

The central temperate Argentinean region is currently affected by rising water tables, allowing higher and more stable maize yields (Zea mays L) when they fluctuate within optimum depth. However, limited information was available for optimizing N management in these environments. Yield response to N rates was explored in soils with influencing grou...

The Argentinean Gran Chaco is one of the global regions with the highest recent rates of agricultural expansion due to soybean production. The area has been heavily deforested during the last 30 years. Despite the economic relevance of soybean for this region, studies that provide options for sustainable management of these production systems are s...

Soybean [Glycine max (L.) Merr.] is one of the most important crops worldwide, and Argentina is the third largest global grain producer and the worlds´ largest meal exporter. Under the continuous challenge of increasing crop yields, especially in the central temperate region of the country, there is a growing need to optimize management in relation...

High 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...

Maíz Flint: Producción sustentable y calidad de grano. Editado por Lucas Borrás Contenido: Prefacio Lucas Borrás Capítulo 1: La relevancia de la sustentabilidad y el suministro responsable para Kellogg. Dave Fritzgerald (Kellogg Irlanda) Capítulo 2: Requisitos para importación en Europa: Caso de maíz flint. Francisco Martí Ribes y Juan Espejo (D...

Sorghum (Sorghum bicolor L. Moench) is traditionally known for its better adaptation to drought when compared to other cereals like maize (Zea mays L.). However, genetic gains are significantly higher for maize than for sorghum, and are known to include drought tolerance. We analyzed maize and sorghum harvested area, yield, and yield stability usin...

Nonstructural carbohydrates in cereals have been widely investigated from physiological, genetic, and breeding perspectives. Nonstructural carbohydrates may contribute to grain filling, but correlations with yield are inconsistent and sometimes negative. Here we ask if there are hidden functions of nonstructural carbohydrates, advance an ecological...

Optimizing grain production implies defining the best management practices for a set of particular environments. Argentinean farmers in the central temperate region are sowing maize at two contrasting sowing dates (September to October and December), exposing their crops to very different growing environments. We tested the influence of management...

The main physiological processes associated with soybean [Glycine max (L.) Merr.] genetic yield progress in central temperate Argentina are largely unknown. This knowledge is critical to identify opportunities to accelerate yield gains via trait‐based hybridization. Our objectives were to: (a) evaluate the influence of biomass accumulation vs. harv...

Maize kernel color and carotenoid concentration are traits valued by the food industry to ensure the quality of their products. Correlations between color and carotenoid concentration have been extensively reported. Based on the concept that chromaticity is modified differently by opaque and translucent materials, we tested the hypothesis that maiz...

Soybean production is challenged to increase yield while maintaining seed protein concentration levels. Variability in protein concentration has been poorly described in many regions, and management options targeting their levels are not available. Our objectives were (i) to describe soybean seed protein in the central production systems of Argenti...

Maize kernel hardness is a key attribute for the global maize processing industry. Breeding for on-farm yield has decreased kernel hardness. However, the underlying changes in zeins and starch composition, mechanistically related to kernel hardness, are unknown. We evaluated changes in zein and starch composition of 32 commercial hybrids released f...

Soybean is commonly cultivated under rainfed conditions being water availability the main constraint. We evaluated the performance of different managements under contrasting water availability to test possible trade‐offs among managements, and to determine physiological variables explaining these yield differences. Four treatments were designed thr...

Argentina is one of the most important maize producers worldwide, and is internationally known for producing hard endosperm maize. The physicochemical characteristics of the maize grain directly affects the milling yield of large endosperm grits, the main dry milling product, and specific grain quality values are demanded by industry. Argentinean t...

Plant density and row spacing are management practices that farmers use to maximize soybean (Glycine max (L.) Merr.) yield. Other canopy aspects related to seedling establishment like spatial (spacing among plants) and temporal (timing of plant emergence) within-row plant-to-plant variability have received less attention. Negative yield effects of...

Core Ideas We used linear mixed effects models to explore maize yield response to applied N. Final models accurately described the observed data ( R ² = 0.93). Best models indicated that yield response to applied N depended on soil N and soil type. Information is useful to optimize management decisions on N fertilizer rates. Resulting models are be...

Argentinean maize (Zea mays L.) is known for its grain hardness, and exporting grain lots are subject to strict regulations regarding physical characteristics and mycotoxin concentrations. Our production system is changing to later sowings, and the use of foliar fungicides is becoming more common due to positive yield responses. In this study, we e...

Grain quality is frequently regarded by agronomists and breeders to be as important as yield. Quality characteristics are the reason why only few plant species are used to satisfy most human requirements for food and fiber. Grain quality has traditionally comprised a group of characteristics that collectively determine the usefulness of the harvest...

Maize grain yield is highly related to the number of kernels that are established during the flowering period. Kernel number depends on the accumulation of ear biomass and the efficiency of using this biomass for kernel set. Ear biomass depends on the rate of plant biomass accumulation and the proportion of this biomass that is allocated to the ear...

Argentina is the single exporter of non-gmo hard endosperm maize to the European Union, and is internationally known for its grain hardness. This special hard endosperm maize supply chain follows strict regulations to ensure a high quality grain. Specific values for test weight, flotation index, grain vitreousness, and screen retention are demanded...

Los experimentos se llevaron a cabo en secano en cuatro localidades (Loc) con diferente potencial de rendimiento: Zavalla, Santa Fé (33°01’S, 60º53’W), Manfredi, Córdoba (31º 49’S, 63º46’W); Ferre, Buenos Aires (34°18’S, 61º12’W) e Intendente Alvear (35°27’S, 63º 57’W), La Pampa. Se sembraron 10 híbridos (Hib) liberados por Dow AgroSciences Argenti...

Prólogo Primer Congreso de Maíz Tardío Cuando revisamos las tendencias de siembra de maíz en Argentina con el grupo técnico-comercial de Dow AgroSciences nos dimos cuenta que el “maíz tardío” había venido para quedarse, ocupando más de la mitad del área cultivada. También observamos que surgían numerosas preguntas sobre la tecnología adecuada para...

Backgrounds and aimsSoybean yield depends on total N uptake, N use efficiency, and harvest index. Nitrogen uptake relays on biological fixation (BNF) and soil absorption. Usually, BNF is considered a yield-related process. However, there is limited information on whether maximizing percent BNF (%BNF) is actually required to maximize N uptake and yi...

Maize (Zea mays L.) grain is an important feedstock for the ethanol-producing industry. However, little is known about the optimum grain quality for optimizing ethanol yielding efficiencies. We specifically investigated the response of ethanol yields (L Mg⁻¹) to kernel hardness, and its physiological determinant endosperm zein protein profiles, as...

Core Ideas Different soybean maturity groups with similar yields are farmed in many temperate regions. Reproductive biology and biomass accumulation during seed set was similar for MGs III and IV. Groups differed in radiation interception, N uptake, and the length of the seed set period. Yield limiting traits tailored for earlier and later soybean...

Developing high protein (HP) cultivars is often precluded by the inverse relationship between protein and yield. We hypothesized that attaining HP concentration based on contrasting seed size impacts crop growth and development differently. We screened 97 soybean genotypes and found lines with HP concentration (∼450 g kg⁻¹) associated with (i) incr...

The genetic basis of grain number determination in sorghum [Sorghum bicolor (L.) Moench] was studied based on canopy growth traits. Traits were crop growth rate (CGR) around flowering, plant reproductive biomass partitioning (PR) to the panicle, and grain‐set efficiency (EG) per unit of accumulated panicle biomass. Previous evidence has shown that...

Maize is one of the most important crops worldwide. The analysis of the influences of genotype, management, and environmental variables on grain yield has important consequences for guiding farmer’s decisions. Argentina is facing relevant changes in its production system, as farmers are planting later in the growing season. It is unclear, however,...

Special hard endosperm maize ( Zea mays L.) adapted for optimum dry milling yields is produced worldwide. Argentine flint maize is internationally known, and specific values for grain vitreousness, floaters, and test weight are demanded by the industry. Agricultural practices aimed to reach these standards, however, are not clear for farmers. Our g...

Maize (Zea mays L.) kernel hardness is of utmost importance for dry-milling processors. Zeins, maize prolamins, are known to be key proteins affecting this trait. We investigated the response of kernel zein profiles to N fertilization in maize hybrids with contrasting kernel hardness (measured as test weight, vitreousness, kernel density, and float...

Maize (Zea mays L.) grain yield has a parabolic response to stand density changes, creating an optimum stand density that maximizes yield. Argentinean commercial hybrids differ in their optimum stand density when grown at similar environments, generating the need to test precommercial hybrids for adequate product management recommendations. For bre...

Argentina is the worldwide single maize (Zea mays L.) exporter of non-GMO flint maize, also called plata maize. This grain is known for high dry-milling yields, the production of large endosperm grits and specific cooking functional properties. But, this special maize has lower yields at farmer fields when compared to regular dent germplasm, and st...

Most maize yield variations are explained by changes in the number of established kernels. Kernel number is, in turn, highly dependent upon ear biomass accumulation around flowering. Both are quantitative traits highly influenced by the environment. Determining the genetic basis of quantitative traits is complex because of usual genetic × environme...

Traditional breeding has been successful in delivering new cultivars with improved grain yield. This is particularly true in the case of maize, with global gains in yield always >2% since the massive introduction of hybrids in the 1960s. The advent of molecular tools in the 1980s, however, demanded an increased knowledge of the whole phenotype for...

Maize (Zea mays L.) stand density selection is an important management practice because yield is maximized at a particular optimum value. Optimum stand density (OSD) varies across environments, and many have argued that current commercial genotypes differ in their optimum stand density for a similar environment. We tested this concept by planting 1...

Seed development is partitioned into a ‘lag’ phase, a ‘seed filling’ phase, and a ‘maturation’ phase. Transitions between phases correspond to seed water concentration (WC) values that are fairly consistent within species. For soybean (Glycine max L.), linear seed filling begins at approximately 85% (WCL) and maximum dry weight is attained at appro...

Individual kernel weight is an important trait for maize yield determination. We have identified genomic regions controlling this trait by using the B73xMo17 population; however, the effect of genetic background on control of this complex trait and its physiological components is not yet known. The objective of this study was to understand how gene...

Maize kernel weight (KW) is associated with the duration of the grain-filling period (GFD) and the rate of kernel biomass accumulation (KGR). It is also related to the dynamics of water and hence is physiologically linked to the maximum kernel water content (MWC), kernel desiccation rate (KDR), and moisture concentration at physiological maturity (...

Crop production increase needed to satisfy a growing world population depends, at least partially, on increasing current genetic gain in yield. Theory proposes that increased genetic gain can be attained using diverse high-yielding parents. Physiological traits, compared to molecular or morphological markers, are hypothesized to better estimate par...

Soybean yields are affected by environmental conditions as well as agronomic practices such us variety selection, nutrition management, plant density, etc. Accurate information about economic and productive impacts of each of these practices is important for farmer’s decision making. The objective of this experiment was to determine the effect of d...

Individual kernel weight (KW) is largely genetically determined, and its variability is achieved through different combinations of rate and duration of kernel growth. Genetic variability for grain-filling patterns has been observed among inbred lines and commercial hybrids, and there is current interest on dissecting its genetic basis. However, sui...

Knowledge on the genetic bases of physiological processes determining maize kernel weight (KW) is relevant for maize yield improvement. However, little is known about the genetic control of KW and its component traits: kernel growth rate (KGR) and grain-filling duration (GFD). We phenotyped several grain-filling traits in 245 RILs from the IBM Syn4...

Current models of sorghum crop growth predict grain number using a calculated plant growth rate around flowering and a genotype-dependent parameter that describes the relationship between both traits. Few values for this parameter have been reported, being similar within triple-dwarf or single-dwarf sorghum genotypes. This approach narrows genotypi...

There is evidence that soybean yield needs to increase at faster rates to satisfy a growing demand. Because yield is mostly determined by the number of harvested seeds, we used a seed number determination framework for phenotyping a large set of cultivars. This framework incorporates biomass accumulation during the seed set period, biomass partitio...

Opportunities for genetic improvement on specific traits require information on available diversity, together with knowledge on heritability estimates and possible trade-off relations among traits. Sixty-five sorghum inbred lines were evaluated for grain filling and other agronomic traits during 2008 and 29 re-evaluated in 2009. Time to anthesis, f...

Because kernel number is the main yield component in grain crops, kernel number per plant or per unit land area is a commonly measured trait in field experiments. This is usually done by means of manual or mechanical counters, which is time consuming. We examined the possibility of counting kernels by means of image analysis. Our method involved ta...

Maize (Zea mays L.) yield is a function of the number harvested kernels per unit land area and the individual kernel weight (KW). Kernel weight and its development show a wide variability due to the genotype, the environment, the crop management, and all possible interactions. Commercial maize hybrids differ markedly in the patterns (rate and durat...

In grain crops, total sink capacity is usually analysed in terms of two components, seed number and individual seed weight. Seed number and potential individual seed weight are established at a similar timing, around the flowering period, and seed weight at maturity is highly correlated with the potential established earlier. It is known that, with...

The capacity to predict time to silking relative to anthesis in maize (Zea mays L.) has important implications for breeding and seed production. We developed a theoretical quantitative framework for simulating the anthesis to silking interval (ASI) based on plant growth and biomass partitioning to the ear. We tested this framework to simulate the p...

Information regarding genotypic variability for maize (Zea mays L.) grain-filling patterns is scarce, especially at the inbred level. We characterized a large set of public and elite proprietary inbred lines for kernel growth traits. Lines were selected to sample divergent kernel size, genetic diversity, and lines released from breeding programs. T...

Developing soybean cultivars with high seed protein concentration has been hampered by the negative correlation between seed protein and seed yield. While previous in vitro studies have documented the impact of assimilate supply to the seed in determining seed protein, in planta studies generally have failed to link seed protein accumulation direct...

Maize (Zea mays L.) grain yield is strongly related to the number of harvested kernels, where kernel number can be increased by synchronously pollinating silks rather than allowing them to be progressively pollinated as they naturally appear from the husks. However, there is scarce evidence on how this practice affects kernel weight (KW) and plant...

In the present study we tested how assimilate availability per kernel at different grain-filling stages may affect maize (Zea mays L.) and sorghum (Sorghum bicolor L. Moench) individual kernel weight (KW). These two species have shown a contrasting KW response to increased assimilate availability at similar seed developmental stages. Plant growth r...

In maize (Zea mays L.), progress towards pistillate flower maturity (silking) is highly dependent upon the environmental conditions around flowering. Under conditions that inhibit plant growth, female flower development is delayed relative to that of the male flowers resulting in an increase in the anthesis–silking interval (ASI). Although variatio...

Understanding source or sink limitations on crop yield is critical for the rational design of agricultural practices as well as breeding strategies. In the present article, we studied sorghum [Sorghum bicolor (L.) Moench] source–sink yield limitations during grain filling, and tested the hypothesis that the time in which kernel maximum water conten...