Modern Cultivars Research Articles

Novel Fusarium wilt resistance genes uncovered in natural and cultivated strawberry populations are found on three non-homoeologous chromosomes

Key MessageSeveral Fusarium wilt resistance genes were discovered, genetically and physically mapped, and rapidly deployed via marker-assisted selection to develop cultivars resistant toFusarium oxysporumf. sp.fragariae, a devastating soil-borne pathogen of strawberry.Fusarium wilt, a soilborne disease caused by Fusarium oxysporum f. sp. fragariae, poses a significant threat to strawberry (Fragariatimesananassa) production in many parts of the world. This pathogen causes wilting, collapse, and death in susceptible genotypes. We previously identified a dominant gene (FW1) on chromosome 2B that confers resistance to race 1 of the pathogen, and hypothesized that gene-for-gene resistance to Fusarium wilt was widespread in strawberry. To explore this, a genetically diverse collection of heirloom and modern cultivars and octoploid ecotypes were screened for resistance to Fusarium wilt races 1 and 2. Here, we show that resistance to both races is widespread in natural and domesticated populations and that resistance to race 1 is conferred by partially to completely dominant alleles among loci (FW1, FW2, FW3, FW4, and FW5) found on three non-homoeologous chromosomes (1A, 2B, and 6B). The underlying genes have not yet been cloned and functionally characterized; however, plausible candidates were identified that encode pattern recognition receptors or other proteins known to confer gene-for-gene resistance in plants. High-throughput genotyping assays for SNPs in linkage disequilibrium with FW1-FW5 were developed to facilitate marker-assisted selection and accelerate the development of race 1 resistant cultivars. This study laid the foundation for identifying the genes encoded by FW1-FW5, in addition to exploring the genetics of resistance to race 2 and other races of the pathogen, as a precaution to averting a Fusarium wilt pandemic.

Agronomic performance of normal‐leafed and semi‐leafless pea (Pisum sativum L.) genotypes

AbstractPea (Pisum sativum L.) is a major pulse crop important as feed and food. Due to the symbiosis with N‐fixing bacteria, it is a valuable component of low‐input cropping systems. The traditional cultivation of peas was limited by their high susceptibility to lodging. This problem was reduced, though not completely solved, by a semi‐leafless mutant. Almost all modern cultivars carry this mutant. It is still an open question as to whether the lack of leaflets may have impaired the productivity. In organic farming, there is still interest in normal‐leafed peas as they can better compete with weeds. To compare the two leaf types, 24 normal‐leafed and 30 semi‐leafless genotypes were evaluated in three environments. Semi‐leafless genotypes had a higher seed (51%) and straw (40%) yield, but most normal‐leafed genotypes were older or less adapted than the semi‐leafless ones. Some newer normal‐leafed cultivars achieved the same yield level, but their cultivation is only possible in mixtures with a supporting crop. Nitrogen content in seed (10%) and in straw (30%) was lower in semi‐leafless genotypes. A negative correlation of yield and N content was observed in both leaf types. However, semi‐leafless peas had a higher N yield in seed and in straw. No correlation between N yield in seed and straw was found, so it is possible to combine a high seed yield with a high N yield in the straw. This is particularly important in organic production systems, where peas are also grown to provide N to the following crop.

Grain carbon isotope composition is a marker for allocation and harvest index in wheat.

The natural 13C abundance (δ13C) in plant leaves has been used for decades with great success in agronomy to monitor water‐use efficiency and select modern cultivars adapted to dry conditions. However, in wheat, it is also important to find genotypes with high carbon allocation to spikes and grains, and thus with a high harvest index (HI) and/or low carbon losses via respiration. Finding isotope‐based markers of carbon partitioning to grains would be extremely useful since isotope analyses are inexpensive and can be performed routinely at high throughput. Here, we took the advantage of a set of field trials made of more than 600 plots with several wheat cultivars and measured agronomic parameters as well as δ13C values in leaves and grains. We find a linear relationship between the apparent isotope discrimination between leaves and grain (denoted as Δδcorr), and the respiration use efficiency‐to‐HI ratio. It means that overall, efficient carbon allocation to grains is associated with a small isotopic difference between leaves and grains. This effect is explained by postphotosynthetic isotope fractionations, and we show that this can be modelled by equations describing the carbon isotope composition in grains along the wheat growth cycle. Our results show that 13C natural abundance in grains could be useful to find genotypes with better carbon allocation properties and assist current wheat breeding technologies.

Modelling potential potato yields: Accounting for experimental differences in modern cultivars

Current potential yield simulations of potato crops can be lower than actual yields observed in fields and the potential yield simulations miss important cultivar differences, for instance in terms of cultivar earliness. This causes issues not only for potential yield simulations but also when estimating the limiting effects of water (and nitrogen) and yield gaps in farmers’ fields. To address this issue, we recalibrated potential yield simulations with WOFOST for five commercial Dutch potato cultivars. An experiment conducted during the 2020 season was used for model calibration while the 2019 version of the same experiment was used for evaluation. The focus of the calibration was on phenology, photosynthesis, and biomass allocation. To aid the latter, the WOFOST biomass allocation table functions were replaced with sigmoid functions and biomass reallocation from haulm to tubers was introduced. In total 19 parameters were adjusted and/or introduced. Twelve of these parameters were not cultivar-specific, e.g. the specific leaf area over the plant developmental stage (SLATB), and the maximum leaf CO2 assimilation rate as function of developmental time (AMAXTB). Seven parameters differed between the cultivars, e.g. the thermal time between emergence and tuber initiation (TSUM1), and most of these were correlated to cultivar earliness. For the calibration year, final yields were underestimated by on average 5.4%, while for the evaluation year the final yield was overestimated by 4.4%. In comparison, the final dry matter yields ranged from 16.4 to 18.5 t ha−1 in 2019 and 15.5–17.5 t ha−1 in 2020. The old WOFOST parameters for potato resulted in an underestimation of 23.7% and 28.7% for, respectively, 2019 and 2020. Improving the parameter sets greatly increased accuracy of the simulations and provided insight in which parameters are cultivar specific and related to cultivar-earliness.

SNP Based Trait Characterization Detects Genetically Important and Stable Multiple Stress Tolerance Rice Genotypes in Salt-Stress Environments.

Soil salinity is a major constraint to rice production in coastal areas around the globe, and modern high-yielding rice cultivars are more sensitive to high salt stress, which limits rice productivity. Traditional breeding programs find it challenging to develop stable salt-tolerant rice cultivars with other stress-tolerant for the saline environment in Bangladesh due to large yield variations caused by excessive salinity fluctuations during the dry (boro) season. We examined trait characterization of 18 advanced breeding lines using SNP genotyping and among them, we found line G6 (BR9621-B-1-2-11) (single breeding line with multiple-stress-tolerant QTL/genes) possessed 9 useful QTLs/genes, and two lines (G4:BR9620-2-7-1-1 and G14: IR 103854-8-3-AJY1) carried 7 QTLs/genes that control the desirable traits. To evaluate yield efficiency and stability of 18 rice breeding lines, two years of field experiment data were analyzed using AMMI (additive main effect and multiplicative interaction) and GGE (Genotype, Genotype Environment) biplot analysis. The AMMI analysis of variance demonstrated significant genotype, environment, and their interaction, accounting for 14.48%, 62.38%, and 19.70% of the total variation, respectively, and revealed that among the genotypes G1, G13, G14, G17, and G18 were shown to some extent promising. Genotype G13 (IR 104002-CMU 28-CMU 1-CMU 3) was the most stable yield based on the AMMI stability value. The GGE biplot analysis indicates 76% of the total variation (PC1 48.5% and PC2 27.5%) which is performed for revealing genotype × environment interactions. In the GGE biplot analysis, genotypes were checked thoroughly in two mega-environments (ME). Genotype G14 (IR103854-8-3-AJY1) was the winning genotype in ME I, whereas G1 (BR9627-1-3-1-10) in ME II. Because of the salinity and stability factors, as well as the highest averages of grain yield, the GGE and AMMI biplot model can explain that G1 and G13 are the best genotypes. These (G1, G6, G13, G14, G17, and G18) improved multiple-stress-tolerant breeding lines with stable grain yield could be included in the variety release system in Bangladesh and be used as elite donor parents for the future breeding program as well as for commercial purposes with sustainable production.

Assessment of oat varieties with different levels of breeding refinement from the Vavilov Institute’s collection applying the method of metabolomic profiling

Metabolomic profiling data obtained through gas chromatography coupled with mass spectrometry are presented. Thirty oat accessions from the collection of the N.I. Vavilov Institute of Plant Genetic resources (VIR) served as the material for the research. Those accessions of Russian and French origin showed different degrees of breeding refinement: from local landraces (the early 1920s) and primitive cultigens (1920–1930s) to modern improved cultivars. Twenty-seven hulled and three naked oat varieties were selected for the study.The main objective of the work was to identify differences among common oat varieties with different degrees of breeding refinement at the level of metabolomic profiles. The resulting data reflected the metabolic state of oat genotypes with different ecogeographic backgrounds. They were compared to assess the content of main metabolite groups important for the formation of the crop’s stress resistance traits as well as nutritional, medicinal and dietary properties of oat grain products. The most informative indicators were identified (fucosterol, chiro-inositol, xylitol; undecylic, threonic, glutamic, ribonic and phosphoric acids; sorbose, fructose, glucose-3-phosphate, and myo-inositol), which helped to make statistically significant differentiation among oat accessions of different origin with various degrees of breeding refinement. Comparing metabolomic profiles of different oat variety groups (landraces, primitive cultigens, and modern cultivars, developed by Russian and French breeders) mirrored distinctive features of the trends followed by different plant breeding schools.This study showed that breeding efforts to improve biochemical indicators in oat grain would require the use of the genetic diversity found in landraces and primitive cultigens collected or developed in the 1920–1930s. This diversity is still preserved and maintained in the global germplasm collection at VIR.

Identification of Aluminum Tolerance in Ethiopian Chickpea (Cicer arietinum L.) Germplasm

Aluminum (Al) toxicity is a major abiotic stress that negatively impacts plant growth and crop productivity. Al ions are released into soil solutions as a function of soil pH, which is in turn determined by a combination of factors, including local geology, historic vegetation and land-use patterns. Selection and use of Al-tolerant crops is a preferred method to address the problem of Al toxicity. The present study evaluated a combination of modern cultivars, advanced breeding lines and a local landrace for Al tolerance using a seedling-based hydroponic assay. Two sequential experiments were conducted to score root and shoot traits in the presence of aluminum. Initially, six Al concentrations (0, 50, 100, 120, 150 and 200 µM) were tested on six chickpea genotypes to identify the single Al concentration that best discriminates among genotypes. Subsequently, 31 chickpea genotypes were evaluated at 0 and 120 µM Al. Progressive declines in trait values were observed in all genotypes with increasing Al, although the degree of sensitivity varied significantly among genotypes. Genotypes were evaluated both for total root length under 120 µM Al and for relative root growth compared to a 0 µM Al control treatment. Considering both parameters, we identified four tolerant chickpea genotypes (DZ-2012-CK-0237, Wollega LV, DZ-2012-CK-0233 and Natoli) and two sensitive genotypes (Akaki and Fetenech). Wollega LV is a local landrace obtained from acidic soil regions of Western Ethiopia, presenting the possibility that historical selection during cultivation on acidic soils might underlie its unusual tolerance. The aluminum tolerance traits identified here are candidates for introgression breeding of new Ethiopian chickpea varieties with potential to increase yield and expand the area of cultivation.

Genome-Wide Association Study of Soybean Germplasm Derived From Canadian × Chinese Crosses to Mine for Novel Alleles to Improve Seed Yield and Seed Quality Traits.

Genome-wide association study (GWAS) has emerged in the past decade as a viable tool for identifying beneficial alleles from a genomic diversity panel. In an ongoing effort to improve soybean [Glycine max (L.) Merr.], which is the third largest field crop in Canada, a GWAS was conducted to identify novel alleles underlying seed yield and seed quality and agronomic traits. The genomic panel consisted of 200 genotypes including lines derived from several generations of bi-parental crosses between modern Canadian × Chinese cultivars (CD-CH). The genomic diversity panel was field evaluated at two field locations in Ontario in 2019 and 2020. Genotyping-by-sequencing (GBS) was conducted and yielded almost 32 K high-quality SNPs. GWAS was conducted using Fixed and random model Circulating Probability Unification (FarmCPU) model on the following traits: seed yield, seed protein concentration, seed oil concentration, plant height, 100 seed weight, days to maturity, and lodging score that allowed to identify five QTL regions controlling seed yield and seed oil and protein content. A candidate gene search identified a putative gene for each of the three traits. The results of this GWAS study provide insight into potentially valuable genetic resources residing in Chinese modern cultivars that breeders may use to further improve soybean seed yield and seed quality traits.

Biomass Allocation Responses to Root Interactions in Wheat Cultivars Support Predictions of Crop Evolutionary Ecology Theory.

The goal of agriculture is to optimize the population yield, but natural selection has produced active competition among plants, which decreases population performance. Therefore, cultivar breeding should be based on group selection, increasing yield by weakening individual competitive responses. We hypothesize that this has occurred inadvertently to some degree, so modern cultivars have weakened competitive traits and responses, such as reduced root proliferation in response to neighboring roots. We conducted a field experiment with eight cultivars of spring wheat that have been released over the last hundred years, which we grew at two densities. Two contrasting wheat cultivars, a landrace and a modern cultivar, were used in a second field experiment on competition within and between the two cultivars to quantify their competitiveness. Finally, a greenhouse experiment was conducted with these two cultivars gown (a) in mixture and monoculture, (b) at four densities, (c) two watering levels, and (d) with permeable vs. non-permeable soil dividers, to study root proliferation responses to competition. Results of field experiment 1 showed that the population aboveground biomass (AGB) had increased, while belowground biomass had decreased over the course of breeding, so that the root to shoot ratio (R/S) was negatively correlated with the release year of the cultivar. The landrace had stronger competitiveness than the modern cultivar in the field experiment 2. There was clear evidence of root proliferation and a resultant reduction in AGB in response to neighboring roots in the greenhouse experiment, and the modern variety showed less root proliferation in response to neighbors. We conclude that the newer cultivar was a weaker competitor but higher-yielding in two ways: (1) it had higher reproductive effort and therefore less allocation to structures that increase competitive ability, and (2) it had reduced root proliferation in response to the roots of neighboring plants. Our results show that wheat plants change their biomass allocation in response to resource levels and the presence of neighboring roots. The presence of root proliferation in the modern cultivar, albeit less than in the landrace, suggests that further increases in yield via group selection are possible.

A functionally divergent SOC1 homolog improves soybean yield and latitudinal adaptation

Soybean (Glycine max) grows in a wide range of latitudes, but it is extremely sensitive to photoperiod, which reduces its yield and ability to adapt to different environments. Therefore, understanding of the genetic basis of soybean adaptation is of great significance for breeding and improvement. Here, we characterized Tof18 (SOC1a) that conditions early flowering and growth habit under both short-day and long-day conditions. Molecular analysis confirmed that the two SOC1 homologs present in soybeans (SOC1a and SOC1b) underwent evolutionary functional divergence, with SOC1a having stronger effects on flowering time and stem node number than SOC1b due to transcriptional differences. soc1a soc1b double mutants showed stronger functional effects than either of the single mutants, perhaps due to the formation of SOC1a and SOC1b homodimers or heterodimers. Additionally, Tof18/SOC1a improves the latitudinal adaptation of cultivated soybeans, highlighting the functional importance of SOC1a. The Tof18G allele facilitates adaptation to high latitudes, whereas Tof18A facilitates adaptation to low latitudes. We demonstrated that SOC1s contribute to floral induction in both leaves and shoot apex through inter-regulation with FTs. The SOC1a-SOC1b-Dt2 complex plays essential roles in stem growth habit by directly binding to the regulatory sequence of Dt1, making the genes encoding these proteins potential targets for genome editing to improve soybean yield via molecular breeding. Since the natural Tof18A allele increases node number, introgressing this allele into modern cultivars could improve yields, which would help optimize land use for food production in the face of population growth and global warming.

Review on Genetic Erosion of Barley (Hordeum vulgare L.) in the Highlands of Ethiopia

Ethiopia is a center of origin and diversity of many cultivated crops and their wild relatives including barley. The richness and range of genetic diversity in Ethiopia, particularly of landraces, is currently subject to serious genetic erosion and irreversible losses due to the changing nature of agricultural production. In this review, the most important factor possibly leading to genetic erosion is the replacement of FV’s by modern cultivars followed by weather variability. Barley, as a food and feed grain, is important to the livelihood of farmers. A number of previous studies have shown higher level of barley diversity in the highland of the country. Traditional barley variety is suffering serious genetic erosion due to displacement by introduced varieties. Knowing the causes of genetic erosion is equally important for devising conservation measures. In conclusion, the use of genetic resources will remain the best way of meeting future food needs and driving the economic and social benefits for the world’s rapidly growing human population.

Genetically related genotypes of cowpea present similar bacterial community in the rhizosphere

Plant breeding reduces the genetic diversity of plants and could influence the composition, structure, and diversity of the rhizosphere microbiome, selecting more homogeneous and specialized microbes. In this study, we used 16S rRNA sequencing to assess the bacterial community in the rhizosphere of different lines and modern cowpea cultivars, to investigate the effect of cowpea breeding on bacterial community assembly. Thus, two African lines (IT85F-2687 and IT82D-60) and two Brazilian cultivars (BRS-Guariba and BRS-Tumucumaque) of cowpea were assessed to verify if the generation advance and genetic breeding influence the bacterial community in the rhizosphere. No significant differences were found in the structure, richness, and diversity of bacterial community structure between the rhizosphere of the different cowpea genotypes, and only slight differences were found at the OTU level. The complexity of the co-occurrence network decreased from African lines to Brazilian cultivars. Regarding functional prediction, the core functions were significantly altered according to the genotypes. In general, African lines presented a more abundance of groups related to chemoheterotrophy, while the rhizosphere of the modern cultivars decreased functions related to cellulolysis. This study showed that the genetic breeding process affects the dynamics of the rhizosphere community, decreasing the complexity of interaction in one cultivar. As these cowpea genotypes are genetically related, it could suggest a new hypothesis of how genetic breeding of similar genotypes could influence the rhizosphere microbiome.

Optimizing manganese and iron delivery for contrasting cultivars of subirrigated greenhouse-grown pot chrysanthemums

Excessive fertilizer use in greenhouse floricultural operations results in low-nutrient use efficiency by plants and poses environmental risk. Here, we optimized the usage of fertilizer manganese (Mn) and iron (Fe) by modern cultivars of subirrigated pot chrysanthemum. Mn and Fe (approximately 100% to 6% of industry standards) were provided in an otherwise balanced nutrient solution during vegetative growth, and all nutrients were removed during reproductive growth. Two experiments were conducted for each nutrient in a naturally lit research greenhouse using a split-plot design with four blocks arranged randomly. Mn (5.00–0.3125 µmol L−1) or Fe (10.56–0.66 µmol L−1) was the main plot and cultivar (“Milton Dark Pink”, “Williamsburg Purple”, and “Olympia White”) was the subplot. The cultivars exhibited contrasting phenotypes. However, any treatment effects on plant yield and inflorescence development and quality were minor, so that Mn or Fe use efficiency increased approximately 16-fold with decreasing supply. Even though leaf Mn, zinc, and calcium levels were occasionally correlated inversely with decreasing Fe delivery, the leaf Mn (44.8–121.8 mg kg−1) and Fe (68.5–121.8 mg kg−1) levels were always considered acceptable. These findings contribute to the development of a low-input practice that would improve the sustainability of floricultural crop production.

Genetic improvement analysis of nitrogen uptake, utilization, translocation, and distribution in Chinese wheat in Henan Province

Genetic improvement analysis of the nitrogen use efficiency (NUE) of wheat ( Tritium aestivum L.) was undertaken to determine the factors guiding NUE in order to develop new wheat cultivars with high yield, high NUE and high quality. To investigate the genetic improvement of wheat NUE and its components, 31 wheat cultivars that had been widely planted in Henan Province since 1941 were grown under high N treatment (HN) and low N treatment (LN). The results indicated that grain yield and NUE have increased significantly with cultivar development since 1941, with an annual genetic gain of 1.03% and 0.74%, respectively, under HN and LN. The significant increase in NUE mainly resulted from a significant increase in N uptake efficiency (NupE) and N utilization efficiency (NutE). NutE was the predominant component contributing to NUE under HN, while NupE was more important than NutE for NUE under LN. The improvement of NutE occurred at the expense of lower grain N content (GNC) as grain yield increased. Breeding was shown to increase N translocation (NTE) by an annual genetic gain of 1.33% and 0.33%, respectively, under HN and LN. N accumulation at the maturity stage was higher in the modern cultivars compared to the pre-modern cultivars, mainly as a result of increased N accumulation during the stem elongation phase. The N translocation capacity of the vegetative tissues increased, and the N translocation efficiency of the sheath and chaff were higher than that of the leaves. Important genetic improvement targets for high NUE include increasing pre-anthesis N assimilation ability and post-anthesis N translocation capacity. Furthermore improvements in wheat breeding should include increasing both N uptake and NHI to improve NUE and reverse the trend of declining GNC. • Higher genetic gain of grain yield and N use efficiency under better environment. • Modern cultivars had higher N accumulation, mainly raised during stem elongation phase. • N utilization efficiency increased at the expense of lower grain N content. • Enhanced N translocation and uptake was important for N use efficiency improvement.

Helitron and CACTA DNA transposons actively reshape the common wheat - AK58 genome.

Transposable elements (TEs) play a pivotal role in reshaping the plant genome. Helitrons represent a new class of transposable elements recently discovered in animals and plants. Helitrons, DNA transposons that replicate via a rolling-circle replication mechanism, are a major driving force behind genome evolution. Since the recent divergence of the modern cultivars (e.g., AK58) and landraces (e.g., Chinese Spring), Helitrons appear to have contributed greatly to genome variability. We first identified 214,665 Helitrons in AK58 by HelitronScanner software and further detected 18,668 tandem duplicated Helitron regions (TDHRs) from all the Helitrons identified. There are 39% of TDHRs (7289) translocated since the divergence of the AK58 and Chinese Spring genomes. What interested us even more are the 462 TDHRs exclusive to the AK58 genome. We also found 235 TDHRs in the 21 centromeric regions and these TDHRs contributed to centromere plasticity. Another very interesting DNA transposon, CACTA, accounting for 15% of AK58 genome, was also the focus of this study because they often inserted into gene rich regions. We found that CACTAs have inserted into many agronomically important genes, such as seed dormancy gene TaMFT and vernalization gene TaVrn1, indicating the important role of CACTAs in modern wheat adaptation.

EVALUATING SPLIT TIMING FERTILIZER APPLICATIONS FOR IMPROVING BREAD BAKING QUALITY OF SOFT RED WINTER WHEAT IN KENTUCKY

There is growing interest among farmers to locally produce high protein and strong gluten wheat that is suitable for bread making and meet the demand of local artisanal bakers in Kentucky. The warm and humid weather in southeast region is ideal for soft red winter wheat (SRW) production which characterized by low protein content. The technique of splitting nitrogen (N) fertilization according to the growth stages has been suggested to improve protein content and its composition. This study evaluated the effect of split N application on yield and baking quality traits of two SRW wheat cultivars grown in the eastern U.S. region in conventional and organic cropping systems. One landrace (Purple Straw) and one modern cultivar (Pembroke 2014 ) were grown under three split N application treatments (ST1, ST2 and ST3). Late N applications (ST3) significantly increased protein content for both years by 5.45% and 6.11% respectively compared to a single application; however, this treatment decreased yield. Cropping system had consistent effects in that conventional system exceeded organic system except for thousand kernel weight. Conventional system had greater yield by 16.11% and 20.17% respectively for both years than organic system. Similarly, sedimentation value (a baking quality trait) was greater by 14.27% and 11.12% respectively in conventional than organic system. This study has generally found improvement in protein content by N application on soft red winter wheat. In addition, more studies should be done in organic system to examine other baking quality traits.

Divergence and conservation of defensins and lipid transfer proteins (LTPs) from sugarcane wild species and modern cultivar genomes.

Plant defensins and lipid transfer proteins (LTPs) constitute a large and evolutionarily diverse family of antimicrobial peptides. Defensins and LTPs are two pathogenesis-related proteins (PR proteins) whose characterization may help to uncover aspects about the sugarcane response to pathogens attack. LTPs have also been investigated for their participation in the response to different types of stress. Despite the important roles of defensins and LTPs in biotic and abiotic stresses, scarce knowledge is found about these proteins in sugarcane. By using bioinformatics approaches, we characterized defensins and LTPs in the sugarcane wild species and modern cultivar genomes. The identification of defensins and LTPs showed that all five defensins groups and eight of the nine LTPs have their respective genes loci, although some was only identified in the cultivar genome. Phylogenetic analysis showed that defensins appear to be more conserved among groups of plants than LTPs. Some defensins and LTPs showed opposite expression during pathogenic and benefic bacterial interactions. Interestingly, the expression of defensins and LTPs in shoots and roots was completely different in plants submitted to benefic bacteria or water depletion. Finally, the modeling and comparison of isoforms of LTPs and defensins in wild species and cultivars revealed a high conservation of tertiary structures, with variation of amino acids in different regions of proteins, which could impact their antimicrobial activity. Our data contributed to the characterization of defensins and LTPs in sugarcane and provided new elements for understanding the involvement of these proteins in sugarcane response to different types of stress.

Natural variations in grain length 10 (GL10) regulate rice grain size

Grain size is an important determinant of grain weight and yield in rice. Although several genes related to grain size have been identified, natural variations in these genes that affect grain size are poorly characterized. Here, we describe the grain length QTL GL10, encoding MADS56, which positively regulates grain length and grain weight. A natural allelic variation of NIL-gl10, containing an ∼1.0-kb deletion in the first exon that abolishes its transcription, results in shorter grain length, lower grain weight and delayed flowering in gl10 plants. The knockout of GL10 in the HJX74 background leads to grain phenotypes similar to that of NIL-gl10, while overexpression of GL10 results in increased grain length and weight and earlier heading date. GL10 regulates grain length by promoting greater longitudinal cell growth in the grain glume. Additionally, GL10 participates in the regulation of gibberellic acid (GA) signaling pathway genes in young panicle tissues. Analysis of GL10 haplotypes shows obvious divergence between the japonica and indica lineages. Our findings reveal an allelic variation of GL10 that may explain differences in grain length among modern cultivars and could be used to breed rice varieties with optimized grain shape.

Breeding More Crops in Less Time: A Perspective on Speed Breeding.

Simple SummaryFeeding our growing population is one of the primary concerns of plant breeders. Plant breeding needs to deliver a steady stream of modern cultivars in a time- and resource-efficient manner. This review discusses the speed breeding (SB) techniques which allow breeders to advance the crop generation in a shorter period of time. In addition, we highlight the current SB applications in major crops and explore ways to integrate SB with new breeding techniques for efficient and faster production of stable lines for basic and applied research.Breeding crops in a conventional way demands considerable time, space, inputs for selection, and the subsequent crossing of desirable plants. The duration of the seed-to-seed cycle is one of the crucial bottlenecks in the progress of plant research and breeding. In this context, speed breeding (SB), relying mainly on photoperiod extension, temperature control, and early seed harvest, has the potential to accelerate the rate of plant improvement. Well demonstrated in the case of long-day plants, the SB protocols are being extended to short-day plants to reduce the generation interval time. Flexibility in SB protocols allows them to align and integrate with diverse research purposes including population development, genomic selection, phenotyping, and genomic editing. In this review, we discuss the different SB methodologies and their application to hasten future plant improvement. Though SB has been extensively used in plant phenotyping and the pyramiding of multiple traits for the development of new crop varieties, certain challenges and limitations hamper its widespread application across diverse crops. However, the existing constraints can be resolved by further optimization of the SB protocols for critical food crops and their efficient integration in plant breeding pipelines.

Plant leaves structural and functional parameters in different breeding periods buckwheat varieties

Crops high productivity is largely determined by plants photosynthetic activity structural and functional indicators genotypic specificity. In this connection, we have conducted field studies on the photosynthetic potential, net productivity, photosynthetic capacity and leaf stomatal conductivity in 11 buckwheat varieties of different selection periods, which were conventionally divided into 3 groups: local populations (Orel region), old varieties - breeding of 1930-1960, and modern varieties - breeding of 1990-2010. It was shown that modern varieties, compared with predecessors, form more powerful photosynthetic potential due to the formation, mainly, large leaf plates, rather than increasing their functioning duration. At the same time, net photosynthetic productivity does not change significantly as a result of breeding. Its value depends to a greater extent on plant vegetation weather conditions than on their hereditary characteristics. At the same time, the leaves photosynthesis, transpiration and stomatal conductivity have undergone significant changes as a breeding result. These indicators values in the formation period and modern cultivars seeds ripening exceeded local populations and older varieties on average by 20.3 … 16.6 and 17.2%, respectively. It is noted that these indicators relationship with the variety final seed productivity is positive, and in some years has a significant value. In this regard, it is proposed in buckwheat crops to carry out directed selection for leaves increasing photosynthetic activity. Work in this direction may well be successful, as indicated by photosynthetic indicators of high heritable conditionality and broad polymorphism. Particular attention should be paid to genotypes with small and dense leaf plates characterized by high photosynthetic activity and low transpiration activity, which will ensure the sun and evaporated water converted energy-efficient use by plants for yield formation.