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Okra (Abelmoschus esculentus L. Moench) is high-valued vegetable and oil crop serving the food, pharmaceutical, paper and oil industry. The production of okra in sub-Saharan Africa (SSA) and globally are hindered by a lack of improved cultivars with drought tolerance. Considerable phenotypic and genotypic variation present in okra genetic resources from SSA is useful for cultivar design with enhanced pod and oil yields, and drought tolerance. However, the genetic diversity present in SSA's okra germplasm collection is yet to be explored for breeding targeting economic and horticultural traits. The objective of this review was to document the research progresses on phenotypic and genotypic divergence analysis and drought tolerance breeding of okra to facilitate breeding and conservation. The review presented the diversity of okra for key agronomic, horticultural and physiological traits for ideotype breeding, gene introgression and drought tolerance improvement. This is followed by key summaries on genetic diversity using conventional and genomic tools, and use of genetic variation in selection programs involving drought-adaptive and economic traits. The review serves as a baseline information to guide future okra breeding and cultivar design under water limited environments in SSA or related agro-ecologies.

Mechanical impedance constrains root growth in most soils. Crop cultivation changed the impedance characteristics of native soils, through topsoil erosion, loss of organic matter, disruption of soil structure, and loss of biopores. Increasing adoption of Conservation Agriculture in high-input agroecosystems is returning cultivated soils to the soil impedance characteristics of native soils, but in the low-input agroecosystems characteristic of developing nations, ongoing soil degradation is generating more challenging environments for root growth. We propose that root phenotypes have evolved to adapt to the altered impedance characteristics of cultivated soil during crop domestication. The diverging trajectories of soils under Conservation Agriculture and low-input agroecosystems has implications for strategies to develop crops to meet global needs under climate change. We present several root ideotypes as breeding targets under the impedance regimes of both high-input and low-input agroecosystems, as well as a set of root phenotypes that should be useful in both scenarios. We argue that a 'whole plant in whole soil' perspective will be useful in guiding the development of future crops for future soils. This article is protected by copyright. All rights reserved.

Weed competitive ability of a crop is one of the most widely explored aspects in the current scenario of aftermaths of synthetic herbicides such as herbicide resistant weeds emergence, residue accumulation in trophic levels; increased demands of organic produce, global climatic shifts, and other environmental issues. Further weed infestations are known to cause much more economic losses relative to crop attacks by pests. To understand the basic characteristics and underlying processes governing the competitive ability of a crop is therefore prudent, particularly in staples such as wheat. We discuss here an overview of the existing attributes of wheat-weed environment, the significance of crop competitiveness and various associated above-ground and below-ground traits (pertaining to early seed vigor and early seedling germination) discerned through biological, classical genetics and high throughput omics toolbox to provide numerous resources in terms of genome and transcriptome sequences, potential QTLs, genetic variation, molecular markers, association mapping studies, and others. Competitiveness is a cumulative response manifested as morphological, physiological, biochemical or allelochemical response ultimately driven through genetic architecture of a crop and its interaction with environment. Development of wheat competitive cultivar thus requires interdisciplinary approaches and germplasm screening to identify potential donors for competitiveness is an attractive and feasible alternative. For which utilization of landraces and other wild species, already proven to house sufficient genetic heterogeneity, thus poses a competitive advantage. Further, the availability of novel breeding techniques such as rapid generation advance could speed up the development of competitive wheat ideotype.

Because plants capture water and nutrients through roots, it was proposed that changes in root systems architecture (RSA) might underpin the 3-fold increase in maize (Zea mays L.) grain yield over the last century. Here we show that both RSA and yield have changed with decades of maize breeding, but not the crop water uptake. Results from X-ray phenotyping in controlled environments showed that single cross (SX) hybrids have smaller root systems than double cross (DX) hybrids for root diameters between 2465 µm and 181µm (P, Emerging opportunity to continue long-term genetic gain in maize yield in the US corn belt by improving the balance between canopy, root, and reproductive growth and development.

Sorghum [Sorghum bicolor (L.) Moench] is a subsistence crop and the main food for populations in arid or semiarid regions and it is appreciated for the production of gluten-free products, forages, raw materials for industrial transformation and packaging. The end-use of different sorghum purposes having various plant or kernel characteristics require specific breeding programs to develop the desired ideotype. Sorghum grains can be classified according to kernel color, tannins and polyphenols content: white, yellow, red, brown, and black. White sorghum is characterized by a low level of total phenolic content and tannins. The advantage of using white sorghum is: increased protein digestibility, nutritional composition and consumer acceptance similar to other cereals. A collection of 117 white grain sorghums was characterized using 10 SSRs and preliminary agronomic observations were made for main traits. SSR analysis revealed from 10 to 33 alleles per locus.Observed heterozygosity was lower than expected according to the reproduction system of sorghum. Phylogenetic analysis revealed 6 main groups of genotypes. Only one group is constituted by genotypes with the same geographical origin (Egypt) while other groups are admixtures of different countries. The principal coordinate analysis revealed good correspondence between genetic profiles and groups evidenced by similar agronomic performances.

C4 crops of agricultural importance all belong to the NADP-malic enzyme (ME) subtype, and this subtype has been the template for C4 introductions into C3 crops, like rice, to improve their productivity. However, the ATP cost for the C4 cycle in both NADP-ME and NAD-ME subtypes accounts for > 40% of the total ATP requirement for CO2 assimilation. These high ATP costs, and the associated need for intense cyclic electron transport and low intrinsic quantum yield Φ CO 2 , are major constraints in realizing strong improvements of canopy photosynthesis and crop productivity. Based on mathematical modelling, we propose a C4 ideotype that utilizes low chloroplastic ATP requirements present in the nondomesticated phosphoenolpyruvate carboxykinase (PEP-CK) subtype. The ideotype is a mixed form of NAD(P)-ME and PEP-CK types, requires no cyclic electron transport under low irradiances, and its theoretical Φ CO 2 is c. 25% higher than that of a C4 crop type. Its cell-type-specific ATP and NADPH requirements can be fulfilled by local energy production. The ideotype is projected to have c. 10% yield advantage over NADP-ME-type crops and > 50% advantage over C3 counterparts. The ideotype provides a unique (theoretical) case where Φ CO 2 could be improved, thereby paving a new avenue for improving photosynthesis in both C3 and C4 crops.

A “smart canopy” ideotype has been proposed with leaves being upright at the top and more horizontal toward the bottom of the plant to maximize light interception and conversion efficiencies, and thus increasing yield. The genetic control of leaf angle has, to date, been studied on one or two leaves, or data have been merged from multiple leaves to generate average values. This approach has limited our understanding of the diversity of leaf angles across layers and their genetic control. Genome-wide association studies and quantitative trait loci mapping studies in sorghum (Sorghum bicolor) were performed using layer-specific angle data collected manually and via high-throughput phenotyping strategies. The observed distribution of angles in indoor and field settings is opposite to the ideotype. Several genomic regions were associated with leaf angle within layers or across the canopy. The expression of the brassinosteroid-related transcription factor BZR1/BES1 and the auxin-transporter Dwarf3 were found to be highly correlated with the distribution of angles at different layers. The application of a brassinosteroid biosynthesis inhibitor could not revert the undesirable overall angle distribution. These discoveries demonstrate that the exploitation of layer-specific quantitative trait loci/genes will be instrumental to reversing the natural angle distribution in sorghum according to the “smart canopy” ideotype.

Background TaCKX wheat gene family members (GFMs) encode the enzyme cytokinin oxidase/dehydrogenase (CKX), which irreversibly degrades cytokinins. The genes are important regulators of cytokinin content and take part in growth and development, with a major impact on yield-related traits. The goal of this research was to test whether these genes might be differentially expressed in the field compared to laboratory conditions and consequently differently affect plant development and yield. Results We compared expression and crosstalk of the TaCKX GFMs and TaNAC2-5A gene in modern varieties grown in a growth chamber (GC) and in the field and looked for differences in their impact on yield-related traits. The TaNAC2-5A gene was included in the research since it was expected to play an important role in co-regulation of these genes. The range of relative expression levels of TaCKX GFMs and TaNAC2-5A gene among tested cultivars was from 5 for TaCKX8 to more than 100 for TaCKX9 in the GC and from 6 for TaCKX8 to 275 for TaCKX10 in the field. The range was similar for four of them in the GC, but was much higher for seven others and TaNAC2-5A in the field. The TaCKX GFMs and TaNAC2-5A form co-expression groups, which differ depending on growth conditions. Consequently, the genes also differently regulate yield-related traits in the GC and in the field. TaNAC2-5A took part in negative regulation of tiller number and CKX activity in seedling roots only in controlled GC conditions. Grain number and grain yield were negatively regulated by TaCKX10 in the GC but positively by TaCKX8 and others in the field. Some of the genes, which were expressed in seedling roots, negatively influenced tiller number and positively regulated seedling root weight, CKX activity in the spikes, thousand grain weight (TGW) as well as formation of semi-empty spikes. Conclusions We have documented that: 1) natural variation in expression levels of tested genes in both environments is very high, indicating the possibility of selection of beneficial genotypes for breeding purposes, 2) to create a model of an ideotype for breeding, we need to take into consideration the natural environment.

Small grain cereals such as wheat, rice and barley are among the most important crops worldwide. Any attempt to increase crop productivity and stability through breeding implies developing new strategies for plant phenotyping, including defining ideotype attributes for selection. Recently, the role of non-foliar photosynthetic organs, particularly the inflorescences, has received increasing attention. For example, ear photosynthesis has been reported to be a major contributor to grain filling in wheat and barley under stress and good agronomic conditions. This review provides an overview of the particular characteristics of the ear that makes this photosynthetic organ better adapted to grain filling than the flag leaf and revises potential metabolic and molecular traits that merit further research as targets for cereal improvement. Currently, the absence of high-throughput phenotyping methods limits the inclusion of ear photosynthesis in the breeding agenda. In this regard, a number of different approaches are presented.

The cultivation of sweet corn is expanding in Brazil, but there are serious constraints about the availability of commercial cultivars. The selection of superior sweet corn genotypes can be performed based on selection indexes based on plant agronomic characteristics. Thus, the objective of this work was to compare selection indexes to select sweet corn genotypes aiming greater productions. The experiment was conducted at the Vegetable Experimental Station of the Federal University of Uberlândia, Campus Monte Carmelo. Eighteen sweet corn accessions (F3 generation) were evaluated. The selection indexes applied to the agronomic characteristics of sweet corn were: direct and indirect, the sum of ranks, desired gains and ideotype indexes. The characteristics evaluated presented significant differences among genotypes, except for stem diameter, prolificacy and grain number per corncob. The coefficients of variation were below 30%, and the genetic parameters were satisfactory for most of the characteristics. The greatest gains with direct selection were in production (21.23%) and productivity of commercial sweet corn ear (15.19%), however, the indirect gains are unsatisfactory for sweet corn selection, and the sum of ranks index provided a balanced distribution of gains. The sweet corn genotypes L2P11, L2P37, P45, L2L5P3, and L5P18 presented a superior performance for the set of characters evaluated.

Atmospheric CO2 concentration [CO2] has increased from 260 to 280 μmol mol−1 (level during crop domestication up to the industrial revolution) to currently 400 and will reach 550 μmol mol−1 by 2050. C3 crops are expected to benefit from elevated [CO2] (e-CO2) thanks to photosynthesis responsiveness to [CO2] but this may require greater sink capacity. We review recent literature on crop e-CO2 responses, related source-sink interactions, how abiotic stresses potentially interact, and prospects to improve e-CO2 response via breeding or genetic engineering. Several lines of evidence suggest that e-CO2 responsiveness is related either to sink intrinsic capacity or adaptive plasticity, for example, involving enhanced branching. Wild relatives and old cultivars mostly showed lower photosynthetic rates, less downward acclimation of photosynthesis to e-CO2 and responded strongly to e-CO2 due to greater phenotypic plasticity. While reverting to such archaic traits would be an inappropriate strategy for breeding, we argue that substantial enhancement of vegetative sink vigor, inflorescence size and/or number and root sinks will be necessary to fully benefit from e-CO2. Potential ideotype features based on enhanced sinks are discussed. The generic 'feast-famine' sugar signaling pathway may be suited to engineer sink strength tissue-specifically and stage-specifically and help validate ideotype concepts. Finally, we argue that models better accounting for acclimation to e-CO2 are needed to predict which trait combinations should be targeted by breeders for a CO2-rich world.

Intercropping is both a well-established and yet novel agricultural practice, depending on one’s perspective. Such perspectives are principally governed by geographic location and whether monocultural practices predominate. Given the negative environmental effects of monoculture agriculture (loss of biodiversity, reliance on non-renewable inputs, soil degradation, etc.), there has been a renewed interest in cropping systems that can reduce the impact of modern agriculture while maintaining (or even increasing) yields. Intercropping is one of the most promising practices in this regard, yet faces a multitude of challenges if it is to compete with and ultimately replace the prevailing monocultural norm. These challenges include the necessity for more complex agricultural designs in space and time, bespoke machinery, and adapted crop cultivars. Plant breeding for monocultures has focused on maximizing yield in single-species stands, leading to highly productive yet specialized genotypes. However, indications suggest that these genotypes are not the best adapted to intercropping systems. Re-designing breeding programs to accommodate inter-specific interactions and compatibilities, with potentially multiple different intercropping partners, is certainly challenging, but recent technological advances offer novel solutions. We identify a number of such technology-driven directions, either ideotype-driven (i.e., “trait-based” breeding) or quantitative genetics-driven (i.e., “product-based” breeding). For ideotype breeding, plant growth modeling can help predict plant traits that affect both inter- and intraspecific interactions and their influence on crop performance. Quantitative breeding approaches, on the other hand, estimate breeding values of component crops without necessarily understanding the underlying mechanisms. We argue that a combined approach, for example, integrating plant growth modeling with genomic-assisted selection and indirect genetic effects, may offer the best chance to bridge the gap between current monoculture breeding programs and the more integrated and diverse breeding programs of the future.

Book of abstract p.110-111; International audience; Pea (Pisum sativum L.) is a key diversification crop but current varieties are not verycompetitive against weeds. The objective of this study was to identify, depending on the typeof cropping system and weed flora, (1) the key pea parameters that drive crop production,weed control and weed contribution to biodiversity, (2) optimal combinations of peaparameter values and crop-management techniques to maximise these goals. For this, virtualexperiments were run, using FLORSYS, a mechanistic simulation model (Colbach et al., 2021,Field Crops Res 261:108006). This individual-based 3D model simulates daily crop-weed seedand plant dynamics over the years, from the cropping system and pedoclimate. Here, thismodel was parameterized for seven pea varieties (Cameor, China, DCG0449, Enduro, Isard,Kayanne, 886/1), from literature and experiments. The latter focused on potential plantmorphology and shading response. Differences between varieties depended on the analysedparameter, e.g., varieties were very similar in terms of leaf biomass ratio (LBR, leaf biomassdivided by above-ground plant biomass) whereas specific leaf area (SLA, ratio of total leaf areadivided by total leaf biomass) at early stages was lower for the two tested spring varieties(Cameor and Kayanne) than for the five winter varieties (except Isard). Then, ten virtualvarieties were created by randomly combining variety-parameter values according to a LatinHypercube Sampling (LHS) plan, respecting parameter ranges and correlations observed in theactual varieties. A global sensitivity analysis was run, using another LHS plan to combine peavarieties, crop rotations and management techniques in nine contrasting situations (e.g.,conventional vs organic, no-till, type of weed flora). Simulated data were analysed withclassification and regression trees (CART). We highlighted (1) Parameters that drive potential(weed-free) yield and competitivity against weeds, depending on variety type (spring vs.winter) and cropping system. These are pointers for breeding varieties to regulate weeds bybiological interactions; (2) Rules to guide farmers to choose the best pea variety, dependingon the production goal and the cropping system; (3) The trade-off between increasing yieldpotential and minimizing yield losses due to weeds when choosing pea variety andmanagement, especially in winter peas. In short, any parameter values that delayed and/orreduced crop emergence decreased potential yield and increased yield loss due to weeds.Conversely, parameter values that increased crop canopy volume (e.g., large LBR duringreproduction stages) and crop growth duration (e.g., delayed flowering onset) had theopposite effect. Shading response was crucial: the more pea varieties increased plant heightand leaf biomass per unit biomass when shaded, the better they controlled weeds. These mainrules describing pea ideotypes were the same for all performance goals, managementstrategies and analyses scales. But the key parameters depended on variety type and aims.For instance, parameters driving germination and pre-emergent growth were crucial for111reducing yield loss in winter pea but not in spring pea or for potential yield. Some varietyfeatures only fitted to particular systems, e.g., parameters delaying pea emergence were onlybeneficial in case of herbicide-spraying and disastrous in unsprayed systems.The more the grown variety differed from the weed-controlling ideotype, the moremanagement rules were needed to compensate. Conversely, if one of the two main weedcontrol levers, herbicide or tillage, was missing from the cropping system, the choice of thepea-variety and/or of other management levers became more important. We are nowapplying this methodology to identify ideal trait combinations for wheat-peaintercrops.FundingINRAE, ANR PeaMUST (ANR-11-BTBR-0002), EU Horizon 2020 (N 727217 ReMIX), FrenchMinistry of Agriculture and Food (CADAR RAID).

The paper presents the results of a 50-year research of the genepool of the winter wheat from the world’s largest wheat collection of N.I. Vavilov Institute of Plant Industry (VIR) to investigate its resistance to the abiotic stress factors of the Moscow region and see how closely it matches the attributes of a wheat ideotype as postulated by N.I. Vavilov in 1935. The critical years in studying the wheat’s winter resistance were 10 years out of 50: excessive water saturation during the year 2013; soil drought in 1988; and atmospheric drought in 1972 and 2010. During the investigation, the following gene pool features were analyzed: frost characterized by the cultivar Sojuz 50 (Russia), rapid temperature change, thawing, ice, and rotting resistance characterized by the cultivars Zarya 2 (Russia), Sv 75268, (Sweden), Caristerm and Tukan (Germany), PP 114-74 and Liwilla (Poland), Maris Ploughman and Granta (Great Britain), Titan (USA), Zdar (Czech), and Zenta (Switzerland); regeneration capacity in spring after poor wintering expressed by the cultivars Pamyati Fedina (Russia), TAW 3668.71 (Germany) and Rmo (Poland); resistance to excessive soil and air saturation exhibited by the cultivars Moskovskaya 39 (Russia), Tukan, Compal, Obelisk, Orestis, and Bussard (Germany); solid standing culm that is resistant to lodging characterized by the cultivars Tukan, Kronjuwel, Compal (Germany), Zenta (Switzerland), Moskovskaya 56 (Russia), and Hvede Sarah (Denmark); resistance to enzyme-mycotic depletion of seeds characterized by the cultivars Tukan, Compal, Obelisk, Orestis, Bussard (Germany), Sv 75268, Helge, VG 73394, Salut, Sv 75355 (Sweden), Zenta (Switzerland), Moskovskaya 39, and Ferrugineum 737.76 (Russia); and resistance to soil and atmospheric drought demonstrated by the cultivars Liessau, Heine Stamm, Severin, Neuzucht 14/4, Haynes, Rus 991, Halle 1020 (Germany), Gama (Poland), Sv 71536 (Sweden), and Moskovskaya 39 (Russia). Moreover, the cultivar Mironovskaya 808 (Ukraine) showed resistance to almost all abiotic stress factors studied. The performed study contributes towards the provision of potential sources of resistance to abiotic stress factors prevalent in the Moscow region that can be incorporated in advanced breeding programs.

Seed yield is a complex trait for many crop species including oilseed rape (OSR) (Brassica napus), the second most important oilseed crop worldwide. Studies have focused on the contribution of distinct factors in seed yield such as environmental cues, agronomical practices, growth conditions, or specific phenotypic traits at the whole plant level, such as number of pods in a plant. However, how female reproductive traits contribute to whole plant level traits, and hence to seed yield, has been largely ignored. Here, we describe the combined contribution of 33 phenotypic traits within a B. napus diversity set population and their trade-offs at the whole plant and organ level, along with their interaction with plant level traits. Our results revealed that both Winter OSR (WOSR) and Spring OSR (SOSR); the two more economically important OSR groups in terms of oil production; share a common dominant reproductive strategy for seed yield. In this strategy, the main inflorescence is the principal source of seed yield, producing a good number of ovules, a large number of long pods with a concomitantly high number of seeds per pod. Moreover, we observed that WOSR opted for additional reproductive strategies than SOSR, presenting more plasticity to maximise seed yield. Overall, we conclude that OSR adopts a key strategy to ensure maximal seed yield and propose an ideal ideotype highlighting crucial phenotypic traits that could be potential targets for breeding.

In the Arctic part of the Nordic region, cultivated crops need to specifically adapt to adverse and extreme climate conditions, such as low temperatures, long days, and a short growing season. Under the projected climate change scenarios, higher temperatures and an earlier spring thaw will gradually allow the cultivation of plants that could not be previously cultivated there. For millennia, Pea (Pisum sativum L.) has been a major cultivated protein plant in Nordic countries but is currently limited to the southern parts of the region. However, response and adaptation to the Arctic day length/light spectrum and temperatures are essential for the productivity of the pea germplasm and need to be better understood. This study investigated these factors and identified suitable pea genetic resources for future cultivation and breeding in the Arctic region. Fifty gene bank accessions of peas with a Nordic landrace or cultivar origin were evaluated in 2-year field trials at four Nordic locations in Denmark, Finland, Sweden, and Norway (55° to 69° N). The contrasting environmental conditions of the trial sites revealed differences in expression of phenological, morphological, crop productivity, and quality traits in the accessions. The data showed that light conditions related to a very long photoperiod partly compensated for the lack of accumulated temperature in the far north. A critical factor for cultivation in the Arctic is the use of cultivars with rapid flowering and maturation times combined with early sowing. At the most extreme site (69°N), no accession reached full maturation. Nonetheless several accessions, predominantly landraces of a northern origin, reached a green harvest state. All the cultivars reached full maturation at the sub-Arctic latitude in northern Sweden (63°N) when plants were established early in the season. Seed yield correlated positively with seed number and aboveground biomass, but negatively with flowering time. A high yield potential and protein concentration of dry seed were found in many garden types of pea, confirming their breeding potential for yield. Overall, the results indicated that pea genetic resources are available for breeding or immediate cultivation, thus aiding in the northward expansion of pea cultivation. Predicted climate changes would support this expansion.

Understanding the interaction between genotype performance and the target environment is the key to improving genetic gain, particularly in the context of climate change. Wheat production is seriously compromised in agricultural regions affected by water and heat stress, such as the Mediterranean basin. Moreover, wheat production may be also limited by the nitrogen availability in the soil. We have sought to dissect the agronomic and physiological traits related to the performance of 12 high-yield European bread wheat varieties under Mediterranean rainfed conditions and different levels of N fertilization during two contrasting crop seasons. Grain yield was more than two times higher in the first season than the second season and was associated with much greater rainfall and lower temperatures. However, the nitrogen effect was rather minor. Genotypic effects existed for the two seasons. While several of the varieties from central/northern Europe yielded more than those from southern Europe during the optimal season, the opposite trend occurred in the dry season. The varieties from central/northern Europe were associated with delayed phenology and a longer crop cycle, while the varieties from southern Europe were characterized by a shorter crop cycle but comparatively higher duration of the reproductive period, associated with an earlier beginning of stem elongation and a greater number of ears per area. However, some of the cultivars from northern Europe maintained a relatively high yield capacity in both seasons. Thus, KWS Siskin from the UK exhibited intermediate phenology, resulting in a relatively long reproductive period, together with a high green area throughout the crop cycle. This study was supported in part by the Spanish projects PID2019-106650RB from the Ministerio de Ciencia e Innovación and IRUEC PCIN-2017-063 from the Ministerio de Economía y Competividad, Spain.

The challenges of plant breeding for disease resistance include identifying genotypes that are resistant to more than one pathogen isolate and defining adequate methods for measuring resistance. We report the identification of Capsicum spp. genotypes resistant to anthracnose caused by two Colletotrichum scovillei isolates using the Genotype-Ideotype Distance Index (GIDI) and multivariate analysis. Forty-one genotypes of chili peppers from three Capsicum species considering unripe and ripe fruits were evaluated for resistance to anthracnose. For inoculation, 20 μL of a suspension containing 1 × 106 conidia/mL were applied in each fruit. Analyses were performed daily for eight days using a scale from 1 (resistant) to 9 (susceptible). Area under the disease progress curve (AUDPC), incubation period, and latent period were evaluated in unripe and ripe fruits, and analyzed using a non-parametric test with ANOVA-type statistic and correlated using the Spearman method. Genotypes were classified using the GIDI and Ward’s hierarchical clustering method. There was variability in germplasm resistance to anthracnose considering the resistance variables and the stage of fruit development. GIDI allowed identifying nine C. baccatum var. pendulum genotypes resistant to isolate 13, and eight C. baccatum var. pendulum plus one C. annuum genotypes resistant to isolate 8. GIDI and Ward’s clustering method identified the same genotypes resistant to isolate 8. Finding resistance in Capsicum genotypes representing different genic complexes means that breeders would be able to introgress resistant alleles from non-cultivated or semi-domesticated into cultivated plants. One genotype, UENF 1628 (C. baccatum var. pendulum), was resistant to two pathogen isolates representing a very interesting source of resistance to anthracnose caused by C. scovillei.

In-depth information on plant phenology of einkorn (Triticum monococcum L. subsp. monococcum) and emmer, (Triticum turgidum subsp. dicoccun (Schrank) Thell) germplasm is indispensable for better utilization of their available genetic resources as underutilized crops, especially under abiotic stress. Whereas; optimization of their phenology is one of the most effective strategies to achieve this goal as it is a key factor for crop adaptation under abiotic stress. The objectives of this study were to integrate quantitative phenotyping methods to describe and explain phenotypic and genotypic differences or similarities in phenological stages within vegetative and reproductive growth phases between einkorn and emmer germplasm; identify combinations of discriminating traits between einkorn and emmer germplasm at successive phenological growth stages; and estimate multivariate distances between einkorn and emmer germplasm based on their geographical sources and stage of genetic improvement. The evaluated germplasm represented a wide range of geographical origins in the Fertile Crescent of West Asia, East Africa, West and East Europe, and North America. The study developed a method for accurate estimation of synchrony and duration of phenological growth stages of the diverse germplasm; and presented a ‘sliding’ scale capable of discriminating between different ‘maturity classes’ of the species on the basis of five phenology indicators, vis: growing degree days in conjunction with plant height, normalized difference vegetative index, color space coordinates, and green gradient-based canopy segmentation. Reliable relationship was established between visual scoring and color measurements of plants based on digital images at different growth stages. This relationship may become useful for research and crop management in resource-limited areas. Accurate prediction of phenological growth stages of einkorn and emmer wheat is essential, not only for ideotype development through simulation and modeling of weather and management effects, but also to help establish a cottage industry to benefit small-scale farmers, and to improve and maintain high-quality end products from these underutilized wheat genetic resources.

Plant height and branch number are essential components of rapeseed plant architecture and are directly correlated with its yield. Presently, improvement of plant architecture is a major challenge in rapeseed breeding. In this study, we first verified that the two rapeseed BnaMAX1 genes had redundant functions resembling those of Arabidopsis MAX1, which regulates plant height and axillary bud outgrowth. Therefore, we designed two sgRNAs to edit these BnaMAX1 homologs using the CRISPR/Cas9 system. The T0 plants were edited very efficiently (56.30%-67.38%) at the BnaMAX1 target sites resulting in homozygous, heterozygous, bi-allelic and chimeric mutations. Transmission tests revealed that the mutations were passed on to the T1 and T2 progeny. We also obtained transgene-free lines created by the CRISPR/Cas9 editing, and no mutations were detected in potential off-target sites. Notably, simultaneous knockout of all four BnaMAX1 alleles resulted in semi-dwarf and increased branching phenotypes with more siliques, contributing to increased yield per plant relative to wild type. Therefore, these semi-dwarf and increased branching characteristics have the potential to help construct a rapeseed ideotype. Significantly, the editing resources obtained in our study provide desirable germplasm for further breeding of high yield in rapeseed.

Nutrient-efficient crops are a solution to the two grand challenges of modern agriculture: improving food security while reducing environmental impacts. The primary challenges are (1) nitrogen (N) and phosphorus (P) efficiency; (2) potassium (K), calcium (Ca), and magnesium (Mg) efficiency for acid soils; and (3) iron (Fe) and zinc (Zn) efficiency for alkaline soils. Root phenotypes are promising breeding targets for each of these. The Topsoil Foraging ideotype is beneficial for P capture and should also be useful for capture of K, Ca, and Mg in acid soils. The Steep, Cheap, and Deep ideotype for subsoil foraging is beneficial for N and water capture. Fe and Zn capture can be improved by targeting mechanisms of metal mobilization in the rhizosphere. Root hairs and phenes that reduce the metabolic cost of soil exploration should be prioritized in breeding programs. Nutrient-efficient crops should provide benefits at all input levels. Although our current understanding is sufficient to deploy root phenotypes for improved nutrient capture in crop breeding, this complex topic does not receive the resources it merits in either applied or basic plant biology. Renewed emphasis on these topics is needed in order to develop the nutrient-efficient crops urgently needed in global agriculture.

In cereals, tillering and leaf development are key factors in the concept of crop ideotype, introduced in the 1960s to enhance crop yield, via manipulation of plant architecture. In the present review, we discuss advances in genetic analysis of barley shoot architecture, focusing on tillering, leaf size and angle. We also discuss novel phenotyping techniques, such as 2D and 3D imaging, that have been introduced in the era of phenomics, facilitating reliable trait measurement. We discuss the identification of genes and pathways that are involved in barley tillering and leaf development, highlighting key hormones involved in the control of plant architecture in barley and rice. Knowledge on genetic control of traits related to plant architecture provides useful resources for designing ideotypes for enhanced barley yield and performance.

Food security is confronted by major threats from crop yield stagnation and global climate change. The benefits of phenotypic plasticity across environments for given crop genotypes are thought to be imperative for high-yielding cropping systems. Given that 3D modeling is increasingly recognized for dissecting crop phenotypic plasticity, it requires an assessment of the potential benefits of architectural adaptation of super rice to different agronomic practices. In this study, we focused on a comprehensive evaluation of the phenotypic plasticity of super rice on the aspects of 3D architectural "reoptimization," photosynthetic productivity, nitrogen economy, and grain yield. A super rice phenotype in superhigh-yielding practice (SH) displays a "reoptimized" morphogenesis in the leaf vertical dispersion and orientation in comparison to that in Farmer's practice (FP). Specifically, a super rice phenotype in SH is provided with a high cumulative rate and peaks of leaf area, increasing the distribution of high leaf inclination angles in comparison to that in FP, particularly in the upper parts of the canopy. These "reoptimizations" sustained profits in light environment within a canopy, leaf area duration, photosynthetic light harvest, and light utilization efficiency and were coordinated with improving nitrogen uptake and assimilation. The current literature indicates that the agronomic plasticity of super rice in architectural "reoptimization" is a promising perspective for high yield formation. Our results suggest that more emphasis should be placed upon agronomic adaptation strategies for super rice across diverse genotypes and environments to further improve crop establishment and photosynthetic productivity.

Developing an appropriate strategy to increase oat yield potential to meet the increasing market demand and overall returns is urgently needed. Crop lodging is the main constraint for improving oat yields. The objectives of this study were aimed to evaluate the effect of leaf posture on crop lodging resistance and lodging related traits, yield performance and their responses to plant populations. Four genotypes with similar yield potential, but differing substantially in leaf architecture, i.e., erect–leaf (E) vs. prostrate–leaf type (P), were tested under three plant population conditions. The results showed that with increasing plant densities from 200 to 600 plants m–2, resistance to stem lodging, resistance to root lodging, and grain yield were decreased, respectively by 21.9%, 14.9% and 6.8% for the P cultivars, but increased by 11.5%, 28.7%, and 3.2%, for E cultivars, averaged across both years. It implied that erect–leaf posture could promote crop resistance to lodging, especially under high plant population condition. Oat plants were more prone to anchorage failure than stem buckling, which was illustrated by the quantitative “safety factor” that was closely related to the visual lodging scores based on field investigation (R2 = 0.56* in 2017). Thus, root lodging should be targeted as the priority criteria in oat breeding for selecting more rigid root system. Taken together, two important attributes of the plant ideotype, i.e., erect–leaf architecture and rigid root system, could be recommended to plant breeders in selecting oat cultivars with improved high–yielding potential and strong lodging resistance.

A large number of genes related to source, sink, and flow have been identified after decades of research in plant genetics. Unfortunately, these genes have not been effectively utilized in modern crop breeding. This perspective paper aims to examine the reasons behind such a phenomenon and propose a strategy to resolve this situation. Specifically, we first systematically survey the currently cloned genes related to source, sink, and flow; then we discuss three factors hindering effective application of these identified genes, which include the lack of effective methods to identify limiting or critical steps in a signaling network, the misplacement of emphasis on properties, at the leaf, instead of the whole canopy level, and the non-linear complex interaction between source, sink, and flow. Finally, we propose the development of systems models of source, sink and flow, together with a detailed simulation of interactions between them and their surrounding environments, to guide effective use of the identified elements in modern rice breeding. These systems models will contribute directly to the definition of crop ideotype and also identification of critical features and parameters that limit the yield potential in current cultivars.

Improving genetic yield potential in major food grade crops such as soybean (Glycine max L.) is the most sustainable way to address the growing global food demand and its security concerns. Yield is a complex trait and reliant on various related variables called yield components. In this study, the five most important yield component traits in soybean were measured using a panel of 250 genotypes grown in four environments. These traits were the number of nodes per plant (NP), number of non-reproductive nodes per plant (NRNP), number of reproductive nodes per plant (RNP), number of pods per plant (PP), and the ratio of number of pods to number of nodes per plant (P/N). These data were used for predicting the total soybean seed yield using the Multilayer Perceptron (MLP), Radial Basis Function (RBF), and Random Forest (RF), machine learning (ML) algorithms, individually and collectively through an ensemble method based on bagging strategy (E-B). The RBF algorithm with highest Coefficient of Determination (R2) value of 0.81 and the lowest Mean Absolute Errors (MAE) and Root Mean Square Error (RMSE) values of 148.61 kg.ha-1, and 185.31 kg.ha-1, respectively, was the most accurate algorithm and, therefore, selected as the metaClassifier for the E-B algorithm. Using the E-B algorithm, we were able to increase the prediction accuracy by improving the values of R2, MAE, and RMSE by 0.1, 0.24 kg.ha-1, and 0.96 kg.ha-1, respectively. Furthermore, for the first time in this study, we allied the E-B with the genetic algorithm (GA) to model the optimum values of yield components in an ideotype genotype in which the yield is maximized. The results revealed a better understanding of the relationships between soybean yield and its components, which can be used for selecting parental lines and designing promising crosses for developing cultivars with improved genetic yield potential.

Maize (Zea mays L.) is a globally important crop species that feeds much of the world’s population and possesses morphology and phenotypic diversity that allow it to be manipulated to produce more productive varieties. Breeding programs have progressively optimized the structural feature of maize plant and organ to increase yield and to improve its adaptability to global climates and environments. Maize plant and organ ideotype development, and the innovative experience of traditional breeders allow us to suggest novel structural features worthy of selection in future breeding programs, including plant type, yield organ traits, architecture of nutrient transfer and epigenetics. And important environmental factors affecting development and epigenetic memory throughout maize life history are analyzed. Comprehensive understanding of maize structural features by means of phenotypic trait panorama provides the initial theoretical foundations for breeding programs based on advanced biotechnology.

International audience; Main conclusionPlant traits of interest for sorghum breeders to develop dual-purpose varieties are stem diameter, flag leaf size, crop cycle, and number of grains per panicle.AbstractTo develop dual-purpose varieties, breeders need to improve traits linked both to grain and biomass production. To identify these traits, we studied the phenotypic plasticity of eighteen traits and the performance of ten contrasting sorghum genotypes, used in West Africa. Trials were carried out in a randomized complete blocks design with four replicates from 2013 to 2016 in Bambey, Sinthiou Malem and Nioro du Rip in Senegal. The results revealed three plant types. The first type, "biomass production", contained genotypes IS15401 and SK5912, and was linked to cycle duration, leaf area, and plant height. The second type, "grain production", grouped the caudatum race sorghum 621B, F2-20 and Soumba, and was associated with the number of grains per panicle and the width of the flag leaf. The third group, "dual-purpose", corresponding to the genotypes Fadda, Nieleni and Pablo, combined some favourable traits for grain and biomass: stem diameter, internode length, number of green leaves and number of grains per panicle. The study showed that high and stable grain yields were associated with stability in flag leaf size, phenology and number of grains per panicle, and a high and stable biomass yield was associated with stability in stem diameter. Those stable plant traits might be of interest for sorghum breeders selecting to develop dual-purpose varieties.

Background Cleistogamic flowers are a main barrier in pollen dispersal for cross-pollination necessary in wheat hybrid breeding. The aim of our study was to gain new knowledge on the biology of wheat flowering, in particular on the differences between the cleisto- and chasmogamic forms which has certainly cognitive significance, but it can also be used in practice when seeking a female and male ideotypes for cross hybridization. Results We characterized the most significant features defining the flowering specificity in two wheat cultivars with contrasting tendency to cleistogamy: Piko (chasmogamous) and Dacanto (cleistogamous). In the field observations we assessed diurnal pattern of anther extrusion and anther extrusion capacity. For the first time we adapted the time lapse method for measuring kinetics of the spikelet movement and 3-D image correlation technique for the non-invasive measurements of potential deformations of the spikelet lemmas. We found that the two cultivars differ in the potential of pollen dispersion for-cross-pollination and in the spikelet kinetics. We also described some anatomical traits that can have potential functional role in floret opening. None of the cultivars showed any symptoms of lemma surface deformation. Conclusions The cleistogamic and chasmogamic wheat cultivars differ significantly in the potential for pollen dispersion for cross-pollination, which is mainly related to anther extrusion capacity. Although none of these features differentiated the cultivars clearly, we assume, based on spikelet kinetics and the lack of lemmas surface deformation, that the water transport and turgor of cells is essential for the floret opening and anther extrusion in wheat. The search for parental ideotype should be supported by marker assisted selection, e.g. based of polymorphisms in genes related to aquaporin biosynthesis.

We summarize recent genome editing studies that have focused on the examination (or reexamination) of plant architectural phenotypes in cereals and the modification of these traits for crop improvement. Plant architecture is defined as the three-dimensional organization of the entire plant. Shoot architecture refers to the structure and organization of the aboveground components of a plant, reflecting the developmental patterning of stems, branches, leaves and inflorescences/flowers. Root system architecture is essentially determined by four major shape parameters—growth, branching, surface area and angle. Interest in plant architecture has arisen from the profound impact of many architectural traits on agronomic performance, and the genetic and hormonal regulation of these traits which makes them sensitive to both selective breeding and agronomic practices. This is particularly important in staple crops, and a large body of literature has, therefore, accumulated on the control of architectural phenotypes in cereals, particularly rice due to its twin role as one of the world’s most important food crops as well as a model organism in plant biology and biotechnology. These studies have revealed many of the molecular mechanisms involved in the regulation of tiller/axillary branching, stem height, leaf and flower development, root architecture and the grain characteristics that ultimately help to determine yield. The advent of genome editing has made it possible, for the first time, to introduce precise mutations into cereal crops to optimize their architecture and close in on the concept of the ideotype. In this review, we consider recent genome editing studies that have focused on the examination (or reexamination) of plant architectural phenotypes in cereals and the modification of these traits for crop improvement.

Identification of traits strongly associated with high yield can help future gene engineering towards improvements of productivity. Here we systematically determine the major architectural and physiological features associated with high yield in two elite historical hybrid rice cultivars, i.e., YLY1 and LYP9. Data from a six-year experiment show that high yield of YLY1 are related to a number of architectural and physiological parameters. Compared to LYP9, YLY1 had 5.5% and 47.3% higher canopy photosynthesis under high and low photosynthetic photon flux densities, respectively, during the grain filling stage, an average 1.5% higher proportion of biomass allocation to above-ground tissues, a 4.5%–10.5% higher photosynthate reserve in leaf sheath before grain filling, and a more efficient photosynthate translocation during grain filling and finally an average 25.2% higher number of productive tillers. These features differ dramatically from features associated with high yield in YLY900 and Yongyou12#, two other high-yielding rice cultivars in China. These identified features and their combinations can support designing new strategies in the future high-yield rice breeding.

Wheat phenology allows escape from seasonal abiotic stresses including frosts and high temperatures, the latter being forecast to increase with climate change. The use of marker-based crop models to identify ideotypes has been proposed to select genotypes adapted to specific weather and management conditions and anticipate climate change. In this study, a marker-based crop model for wheat phenology was calibrated and tested. Climate analysis of 30 years of historical weather data in 72 locations representing the main wheat production areas in France was performed. We carried out marker-based crop model simulations for 1019 wheat cultivars and three sowing dates, which allowed calculation of genotypic stress avoidance frequencies of frost and heat stress and identification of ideotypes. The phenology marker-based crop model allowed prediction of large genotypic variations for the beginning of stem elongation (GS30) and heading date (GS55). Prediction accuracy was assessed using untested genotypes and environments, and showed median genotype prediction errors of 8.5 and 4.2 days for GS30 and GS55, respectively. Climate analysis allowed the definition of a low risk period for each location based on the distribution of the last frost and first heat days. Clustering of locations showed three groups with contrasting levels of frost and heat risks. Marker-based crop model simulations showed the need to optimize the genotype depending on sowing date, particularly in high risk environments. An empirical validation of the approach showed that it holds good promises to improve frost and heat stress avoidance.

Parallels exist between the domestication of new species and the improvement of various crops through selection on traits which favor the sowing, harvest and retention of yield potential and the directed efforts to improve their agronomics, disease resistance and quality characteristics. Common selection pressures may result in the parallel selection of orthologs underlying these traits and homologies between crop species can be exploited by plant breeders to improve germplasm. Perennial grains and oilseeds are a class of proposed crops for improving the diversity and sustainability of agricultural systems. Maximilian sunflower (Helianthus maximiliani Schrad.) is a perennial crop wild relative of sunflower (Helianthus annuus L.) and a candidate perennial oilseed species. Understanding parallels between cultivated H. annuus and H. maximiliani may provide new tools for the development of Maximilian sunflower and other wild relatives of sunflower as crops to enhance functional diversity in cropping systems. F2 populations of Maximilian sunflower segregating for traits associated with the domestication ideotype of cultivated sunflower including branching architecture, capitulum morphology and flowering time were developed to investigate parallels between H. maximiliani and H. annuus. Genotype-by-sequencing (GBS) was employed to genotype novel Maximilian sunflower populations and perform quantitative-trait-loci (QTL) analysis. A total of 11 QTL in five regions were identified across 21 linkage groups using 4142 GBS derived single nucleotide polymorphism markers called using the sunflower reference genome as a guide. A major QTL on linkage group 17b, associated with aspects of floral development and apical dominance, was discovered and corresponds with a known domestication QTL hotspot in H. annuus and candidate genes were identified. This suggests the potential to exploit orthologs for neo-domestication of H. maximiliani for traits such as branching architecture, timing of anthesis, and capitulum size and morphology for the development of a perennial oilseed crop from wild relatives of cultivated sunflower.

Increased plant density markedly affects canopy morphophysiological activities and crop productivity. This study aims to model maize canopy final morphology under increased interplant competition by revising a functional–structural plant model, i.e., ADEL-Maize. A 2-year field experiment was conducted at Mengcheng, Anhui Province, China, in 2016 and 2018. A randomized complete block design of five plant densities (PDs), i.e., 4.5, 6, 7.5, 9, and 15 plants m–2, with three replications was applied using a hybrid, i.e., Zhengdan 958. Canopy morphology at different PDs was measured with destructive samplings when maize canopy was fully expanded. The relationship of changes of organ morphology in relation to increased plant density was analyzed based on 2016 data. The ADEL-Maize was first calibrated for the hybrid at 4.5 plants m–2 and then revised by introducing relationships identified from 2016 data, followed by independent validation with 2018 field data. A heatmap visualization was shown to clearly illustrate the effects of increased plant density on final morphology of laminae, sheaths, and internodes. The logarithmic + linear equations were found to fit changes for the organ size versus increased plant density for phytomers excluding ear position or linear equations for the phytomer at ear position based on 2016 field data. The revision was then further tested independently by having achieved satisfactory agreements between the simulations and observations in canopy size under different PDs with 2018 field data. In conclusion, this study has characterized the relationship between canopy morphology and increased interplant competition for use in the ADEL-Maize and realized the simulations of final size of laminae, sheaths, and internodes, as affected by increased plant density, laying a foundation to test an ideotype for maize withstanding high interplant competition.

Using classical breeding, plant breeders envision a plant type whose yield they aim to enhance by selecting for individual traits to create model/ideal plants or ideotypes. To achieve this, those factors restricting yield need to be identified and controlled through the use of new technologies to achieve the desired ideotype. This study aimed to determine the ideotype of seven genetically modified (GM) and non-GM rice (Oryza sativa L.) cultivars. Field experiments were carried out in three isolated regions in the north of Iran under the Iranian bio-safety standard protocol. Four of the GM cultivars carried the cry1Ab gene in the vegetative stage while three non-GM cultivars served as the control. R2 values showed that five, six and seven variables in Sari, Amol and Rasht regions accounted for 63 %, 52 % and 74 % of paddy yield variation, respectively. In the same three regions, paddy yield variation due to white heads accounted for 28.38 %, 8.45 % and 3.95 % of the total variation in paddy yield, respectively. The total estimated variation in paddy yield in Sari, Amol and Rasht was 1810.50, 2377.6 and 2176.47 kg ha−1, respectively. Average data over the three regions indicated that highest loss in paddy yield was observed in non-GM ‘Nemat’, ‘Khazar’ and ‘Tarom Hashemi’. GM cultivars derived from ‘Khazar’ showed significantly lower paddy yield loss than the non-GM parent. Dead heart, a condition that occurs in the vegetative stage in which the stem borer larva enters the stem and feeds on the growing shoot, causing the central shoot to dry, as well as white heads, which is a condition in which whole ear heads of adult plants become dry and yield chaffy grains, in all three regions were important variables contributing to paddy yield loss. In the future, producing GM rice resistant to striped stem borer with an active promoter in the reproductive growth stage might allow farmers to reduce a significant part of paddy yield loss resulting from white heads, which is directly negatively correlated with filled spikelets per panicle (R2 = -0.57**), in order to achieve an ideotype.

Root phenotypic plasticity has been proposed as a target for the development of more productive crops in variable environments. However, the plasticity of root anatomical and architectural responses to environmental cues is highly complex, and the consequences of these responses for plant fitness are poorly understood. We propose that root phenotypic plasticity may be beneficial in natural or low-input systems in which the availability of soil resources is spatiotemporally dynamic. Crop ancestors and landraces were selected with multiple stresses, competition, significant root loss and heterogenous resource distribution which favored plasticity in response to resource availability. However, in high-input agroecosystems, the value of phenotypic plasticity is unclear, since human management has removed many of these constraints to root function. Further research is needed to understand the fitness landscape of plastic responses including understanding the value of plasticity in different environments, environmental signals that induce plastic responses, and the genetic architecture of plasticity before it is widely adopted in breeding programs. Phenotypic plasticity has many potential ecological, and physiological benefits, but its costs and adaptive value in high-input agricultural systems is poorly understood and merits further research.

Pigeonpea productivity is greatly constrained by poor plant ideotype of existing Indian cultivars. Enhancing pigeonpea yield demands a renewed focus on restructuring the ideal plant type by using more efficient approaches like genomic tools. Therefore, the present study aims to identify and validate a set of QTLs/gene(s) presumably associated with various plant ideotype traits in pigeonpea. A total of 133 pigeonpea germplasms were evaluated along with four checks in the augmented design for various ideotype traits i.e. initiation of flowering (IF), days to 50% flowering (DFF), days to maturity (DM), plant height (PH), primary branches (PB), seeds per pod (SP) and pod length (PL). We observed significant genetic diversity in the germplasm lines for these traits. The genetic control of IF, DFF, DM and PH renders these traits suitable for detection of marker trait associations. By using residual maximum likelihood algorithm, we obtained appropriate variance–covariance structures for modeling heterogeneity, correlation of genetic effects and non-genetic residual effects. The estimates of genetic correlations indicated a strong association among earliness traits. The best linear unbiased prediction values were calculated for individual traits, and association analysis was performed in a panel of 95 diverse genotypes with 19 genic SSRs. Out of five QTL-flanking SSRs used here for validation, only ASSR295 could show significant association with FDR and Bonferroni corrections, and accounted for 15.4% IF, 14.2% DFF and 16.2% DM of phenotypic variance (PV). Remaining SSR markers (ASSR1486, ASSR206 and ASSR408) could not qualify false discovery rate (FDR) and Bonferroni criteria, hence declared as false positives. Additionally, we identified two highly significant SSR markers, ASSR8 and ASSR390 on LG 1 and LG 2, respectively. The SSR marker ASSR8 explained up to 22 and 11% PV for earliness traits and PB respectively, whereas ASSR390 controlled up to 17% PV for earliness traits. The validation and identification of new QTLs in pigeonpea across diverse genetic backgrounds brightens the prospects for marker-assisted selection to improve yield gains in pigeonpea.

Development of Brazilian potato cultivars adapted to different growing conditions, production systems and regions of the country is very important to increase the competitiveness of the national potato chain. In this sense, the objective of this work was to verify the performance of advanced potato clones for tuber yield traits, vine maturity and frying quality. An experiment was carried out in Pelotas-RS in spring, 2014. A set of nine advanced potato clones and two control cultivars were evaluated using a randomized complete block design with four replicates. Plots consisted of single rows of 20 plants spaced at 0.80 m between rows and 0.30 m between plants. The data of each trait were submitted to the deviance analysis, estimated the genetic values and selected the best genotypes using selection indices of the sum of ranks and the lowest distance from the ideotype. Clones F131-08-26 and F183-08-01, and the check ‘Asterix’ were distinguished for yield of marketable tubers. F183-08-01 and the control stood out for specific gravity and average tuber weight. Clone F161-07-02 ranked among the best for specific gravity, frying color and vine maturity. F97-07-04 and F183-08-01 and the check ‘Asterix’ were the best according to the selection indices, however, would result in losses in the frying color and vine maturity traits. RESUMO A obtenção de cultivares nacionais de batata adaptadas a diferentes condições de cultivo, sistemas e regiões do Brasil é muito importante para aumentar a competitividade da cadeia brasileira da batata. Neste sentido, o objetivo deste trabalho foi verificar o desempenho de clones de batata para caracteres de rendimento de tubérculos, ciclo vegetativo e qualidade de fritura. O experimento foi realizado em Pelotas-RS na primavera de 2014. Foi avaliado um conjunto de nove clones de batata e duas cultivares testemunhas, no delineamento experimental de blocos casualizados com quatro repetições e as parcelas constituídas de uma linha com 20 plantas, espaçadas em 0,80 m entre linhas e 0,30 m entre plantas. Os dados de cada caráter avaliado foram submetidos à análise de deviance. Foram estimados os valores genéticos e selecionados os melhores genótipos por índices de seleção da soma dos “ranks” e da menor distância ao tipo ideal. Para rendimento de tubérculos comerciais destacaram-se os genótipos F131-08-26, Asterix e F183-08-01, sendo os dois últimos genótipos também destaques para peso específico e massa média de tubérculos. O clone F161-07-02 foi classificado entre os melhores para peso específico, cor de fritura e ciclo vegetativo. Os clones F97-07-04 e F183-08-01 e a cultivar testemunha Asterix foram os melhores de acordo com os índices de seleção, que, no entanto, resultaria em perdas nos caracteres cor de fritura e ciclo vegetativo.

Ornamental use of Capsicum genus chili peppers has expanded due to easy seed propagation, short germination period, diversified fruit colors and harmony of potted plants. The ornamental plant sector requires cultivars adapted to different cultivation conditions in pots and gardens. Breeding programs can use heterosis and combining ability information, aiming to commercially explore hybrids or develop populations for lineage selection with desirable characteristics. However, the ornamental chili pepper field lacks studies with this data. In this study, combining ability of C. annuum accessions was determined for ornamental purposes and hybrid combinations were identified based on heterosis values. Fifteen hybrids were obtained from diallel crosses of six genotypes of C. annuum, from March to September 2014, under greenhouse conditions, grown in five-liter pots in experimental design of randomized blocks with 10 repetitions and one plant per plot. Morpho-agronomic characterization was conducted based on eight quantitative descriptors: plant height (before and after fruiting); canopy diameter; days to flourishing; days to fruiting; fruit length and diameter, and number of fruits per plant. Both additive and dominance effects play important role in controlling the studied characters, indicating hybrid exploitation as well as development of superior lineages from the progress of segregating generations. Negative heterosis values resulted in reduction in height, time for flourishing and fruiting, as well as fruit diameter and length, which are desirable for ornamental Capsicum breeding program. Considering an ideotype for ornamental chili pepper cultivars, the hybrids UENF 1626 x UENF 1750, UENF 1750 x UENF 2030 and UENF 1626 x UENF 2030 can be recommended for cultivation with ornamental purposes.

The erect panicle (Ep) type is an important characteristic for japonica super rice in Northeast China and plays a significant role in enhancing yield. The Ep type is considered to be a genetic ideotype resource to the japonica super rice group by virtue of its agronomic advantages such as grain number per panicle and biomass. This study addresses the effects of nitrogen and planting density conditions on yielding performance regarding panicle type (PT) using the recombinant inbred line (RIL) population derived from the cross between an Ep variety Liaogeng 5 and non-Ep variety Wanlun 422. The genetics underlying the Ep type proved to be robust not only for panicle-type optimization but also plant height, panicle length, flag leaf length and seed density. We also found that regardless of nitrogen and density, correlation between harvest index (HI) and plant height was not significant in Ep type whatever the nitrogen and density. The application of Ep type provides a potential strategy for yield improvement by increasing biomass through HI maintainable in rice.

Competition is a common phenomenon in agriculture production. Research on the relationship between competitive ability and crop yield is extensive, but the results have been inconsistent. Few studies have focused on the relationship between population competitive intensity and yield of maize ( Zea mays L.) cultivars. The main objective of this study was to determine if a consistent relationship exists between maize yield and competitive ability. A two-year field experiment was conducted, employing a de Wit replacement series design. When two maize cultivars were grown in a mixture, yield was reduced for the modern cultivar and increased for the older cultivar. In each replacement series, per plant level yield of each cultivar, and population level yield of the mixture, decreased with increasing proportion of the older cultivar. Competitive ratio (CR) reflected differences in competitive ability of the three maize cultivars. In each replacement series, population competition pressure (PCP) increased with increasing proportion of the older cultivar, indicating that the older cultivar was a strong competitor. Biomass yield, grain yield, harvest index, thousand-kernel weight, and kernel number per plant, were negatively correlated with PCP. Our results demonstrated that inter-cultivar competition affects maize productivity, and increasing PCP will decrease translocation of assimilates to grain and, ultimately, reduce yield. Therefore, there is a negative correlation between population competitive intensity and yield performance in maize, breeders should develop a communal ideotype that would not perform well in competition in future.

In 1996, a mega project that aimed to develop rice varieties with super-high yield potential (super rice) was launched by the Ministry of Agriculture (MOA) in China using a combination of the ideotype approach and intersubspecific heterosis. Significant progress has been made in the last two decades, with a large number of super rice varieties being approved by the MOA and the national average grain yield being increased from 6.21 t ha −1 in 1996 to 6.89 t ha −1 in 2015. The increase in yield potential of super rice was mainly due to the larger sink size which resulted from larger panicles. Moreover, higher photosynthetic capacity and improved root physiological traits before heading contributed to the increase in sink size. However, the poor grain filling of the later-flowering inferior spikelets and the quickly decreased root activity of super rice during grain filling period restrict the achievement of high yield potential of super rice. Furthermore, it is widely accepted that the high yield potential of super rice requires a large amount of N fertilizer input, which has resulted in an increase in N consumption and a decrease in nitrogen use efficiency (NUE), although it remains unclear whether super rice per se is responsible for the latter. In the present paper, we review the history and success of China's Super Rice Breeding Program, summarize the advances in agronomic and physiological mechanisms underlying the high yield potential of super rice, and examine NUE differences between super rice and ordinary rice varieties. We also provide a brief introduction to the Green Super Rice Project, which aims to diversify breeding targets beyond yield improvement alone to address global concerns around resource use and environmental change. It is hoped that this review will facilitate further improvement of rice production into the future.

Super rice breeding in China has been very successful over the past 3 decades, and the Chinese government has made great efforts to support breeding and cultivation of both conventional and hybrid super rice. In this review, we focus on the progress in and potential of super rice breeding. After the establishment of the breeding theory and strategy of “generating an ideotype with strong heterosis through inter-subspecies hybridization, by using gene pyramiding to combine elite traits through composite-crossing to breed super rice varieties with both ideotype and strong hybrid vigor”, a series of major breakthroughs have been achieved in both conventional and super hybrid rice breeding. A number of new genetic materials with ideotype have been created successfully, and the Ministry of Agriculture of China has approved 156 novel super rice varieties and combinations for commercialization. During the Developing the Super Rice Varieties Program, great attention has also been paid to the integration and demonstration of the rice production technology. Collaboration between industry and university researchers has led to technological innovations and initiation of a demonstration system for super hybrid rice. With widespread cultivation of super rice with higher quality and yield, as well as resistance or tolerance to abiotic or biotic stresses, the yield of rice production per unit has reached a new level. In addition to increased quality and yield, hybrid rice breeding has also led to improvements in many other agronomic traits, such as resistance to pests and diseases, resistance to lodging, and optimized light distribution in population. Achievements in super rice breeding and innovation in rice production have made major contributions to the progress in rice sciences and worldwide food security.

Breeding towards root-centric ideotypes can be a relatively quick trait-based strategy to improve crop resource use efficiency. Irrigated agriculture represents a crucial and expanding sector, but its unique parameters require traits distinct from previously proposed rainfed ideotypes. We propose a novel irrigated ideotype that integrates traits across multiple scales to enhance resource use efficiency in irrigated agroecosystems, where resources are concentrated in a relatively shallow 'critical zone'. Unique components of this ideotype include rapid transplant recovery and establishment, enhanced exploitation of localized resource hotspots, adaptive physiological regulation, maintenance of hydraulic conductivity, beneficial rhizosphere interactions, and salinity/waterlogging avoidance. If augmented by future research, this target could help to enhance agricultural sustainability in irrigated agroecosystems by guiding the creation of resource-efficient cultivars.

The ideotype is a theoretical model of an archetypal cultivated plant. Recent progress in genome editing is aiding the pursuit of this ideal in crop breeding. Breeding is relatively straightforward when the traits in question are monogenic in nature and show Mendelian inheritance. Conversely, traits with a diffuse, polygenic basis such as abiotic stress resistance are more difficult to harness. In recent years, many genes have been identified that are important for plant domestication and act by increasing yield, grain or fruit size or altering plant architecture. Here, we propose that (a) key monogenic traits whose physiology has been unveiled can be molecularly tailored to achieve the ideotype; and (b) wild relatives of crops harboring polygenic stress resistance genes or other traits of interest could be de novo domesticated by manipulating monogenic yield-related traits through state-of-the-art gene editing techniques. An overview of the genomic and physiological challenges in the world’s main staple crops is provided. We focus on tomato and its wild Solanum (section Lycopersicon) relatives as a suitable model for molecular design in the pursuit of the ideotype for elite cultivars and to test de novo domestication of wild relatives.

In Tamilnadu, Ariyalur district contributes a major share of cluster onion production. An ideotype popular among the growers of this locality is preferred by consumers of entire state for its size, storability and taste. Hence the present investigation was carried out the in a farmer’s field at Vennallur located in Ariyalur District during 2017. The experiment was laid out with seven treatments in randomized block design. Each treatment was replicated thrice. The treatments included three kinds of practices adopted by the farmers of the tract and four others where bulky organic manures (Vermicompost, Poultry manure) and concentrated organic manures (Neem cake and Groundnut cake) were substituted on ‘N’ equivalent basis, along with biofertilizers (Azospirillum and Phosphobacteria) and foliar spray of Panchakavya (3%). All the four treatments with organic inputs (T4 to T7) gave better results, when compared to farmer’s practice (T1 and T2). Though T3 was the best, incorporation of Poultry manure+Neem cake (T6) and Poultry manure+Groundnut cake (T7) along with Biofertilizer+Panchakavya 3 % improved the yield significantly in order.

14 Pág., Knowledge of the agronomic and physiological traits associated with genetic gains in yield is essential to improve understanding of yield-limiting factors and to inform future breeding strategies. The aim of this paper is to dissect the agronomic and physiological traits related to genetic gain and to propose an ideotype with high yield that is best adapted to Spanish Mediterranean environments. Six semi-dwarf (i.e. modern) durum wheat genotypes were grown in a wide range of growing conditions in Spain during two successive years. Diverse agronomic, physiological and leaf morphological traits were evaluated. Kernels spike-1 was the yield component most affected by the genetic gain. While no interaction between genotype and growing conditions existed for grain yield, the more productive genotypes were characterized by a plant height of around 85 cm, small erect flag leaves, more open stomata, a better balance between N sources and N sinks and a higher capacity to re-fix CO2 respired by the grain. Moreover, in general the non-laminar parts of the plants play a key role in providing assimilates during grain filling. The high heritability of most of the studied parameters allows their consideration as traits for phenotyping durum wheat better adapted to a wide range of Mediterranean conditions., This study was supported by the Spanish project AGL2016-76527-R from MINECO, Spain. Fadia Chairi is the recipient of an FPI doctoral fellowship from the same institution. Jose Luis Araus acknowledges the support from the ICREA Academia of the Catalan Government, Spain.

The improvement of panicle exsertion length (PEL) in wheat (Triticum aestivum L.) breeding programs is an emerging objective to improve yield potential, and serves as a complement to the wheat ideotype. In this study we aimed to advance the current understanding of genetic mechanisms underlying panicle exsertion in wheat. Two related recombinant inbred line populations sharing common parent H461 were used to identify and compare quantitative trait loci (QTL) controlling PEL. Using two high-density genetic linkage maps, 13 putative QTL for PEL were detected on chromosomes 1B, 1D, 2B, 2D, 4A, 4B, 5B, 6D, 7A, and 7B; each QTL explained 5.7–15.6% of the phenotypic variation. Among these 13 QTL, nine were independent; the other two pairs derived from H461 were validated to be common QTL based on newly developed high-resolution melt markers. Further, plant height (PH) was measured to perform covariance QTL analysis with eight major QTL; three of them derived from the wheat variety CM107 were not affected by PH. Pleiotropic effects on yield-related traits (PH, spike length, spikelet number per spike, spikelet density, kernel number per spike, kernel length, and thousand kernel weight) of the eight major QTL were also evaluated. These eight QTL may be valuable for fine mapping and marker-assisted selection in wheat breeding programs.

Global population increase coupled with rising urbanization underlies the predicted need for 60% more food by 2050, but produced on the same amount of land as today. Improving photosynthetic efficiency is a largely untapped approach to addressing this problem. Here, we scale modeling processes from gene expression through photosynthetic metabolism to predict leaf physiology in evaluating acclimation of photosynthesis to rising [CO2]. Model integration with the yggdrasil interface enabled asynchronous message passing between models. The multiscale model of soybean photosynthesis calibrated to physiological measures at ambient [CO2] successfully predicted the acclimatory changes in the photosynthetic apparatus that were observed at 550 ppm [CO2] in the field. We hypothesized that genetic alteration is necessary to achieve optimal photosynthetic efficiency under global change. Flux control analysis in the metabolic system under elevated [CO2] identified enzymes requiring the greatest change to adapt optimally to the new conditions. This predicted that Rubisco was less limiting under elevated [CO2] and should be down-regulated allowing re-allocation of resource to enzymes controlling the rate of regeneration of ribulose-1:5 bisphosphate (RubP). By linking the GRN through protein concentration to the metabolic model it was possible to identify transcription factors (TF) that matched the up- and down-regulation of genes needed to improve photosynthesis. Most striking was TF GmGATA2, which down-regulated genes for Rubisco synthesis while up-regulating key genes controlling RubP regeneration and starch synthesis. The changes predicted for this TF most closely matched the physiological ideotype that the modeling predicted as optimal for the future elevated [CO2] world.