Lines Of Rye Research Articles

Assessment of the Combinational Ability of Inbred Winter Rye Lines in Plant Height

Assessment of the Combinational Ability of Inbred Winter Rye Lines in Plant Height

Scald resistance in hybrid rye (Secale cereale): genomic prediction and GWAS.

Rye (Secale cereale L.) is an important cereal crop used for food, beverages, and feed, especially in North-Eastern Europe. While rye is generally more tolerant to biotic and abiotic stresses than other cereals, it still can be infected by several diseases, including scald caused by Rhynchosporium secalis. The aims of this study were to investigate the genetic architecture of scald resistance, to identify genetic markers associated with scald resistance, which could be used in breeding of hybrid rye and to develop a model for genomic prediction for scald resistance. Four datasets with records of scald resistance on a population of 251 hybrid winter rye lines grown in 2 years and at 3 locations were used for this study. Four genomic models were used to obtain variance components and heritabilities of scald resistance. All genomic models included additive genetic effects of the parental components of the hybrids and three of the models included additive-by-additive epistasis and/or dominance effects. All models showed moderate to high broad sense heritabilities in the range of 0.31 (SE 0.05) to 0.76 (0.02). The model without non-additive genetic effects and the model with dominance effects had moderate narrow sense heritabilities ranging from 0.24 (0.06) to 0.55 (0.08). None of the models detected significant non-additive genomic variances, likely due to a limited data size. A genome wide association study was conducted to identify markers associated with scald resistance in hybrid winter rye. In three datasets, the study identified a total of twelve markers as being significantly associated with scald resistance. Only one marker was associated with a major quantitative trait locus (QTL) influencing scald resistance. This marker explained 11-12% of the phenotypic variance in two locations. Evidence of genotype-by-environment interactions was found for scald resistance between one location and the other two locations, which suggested that scald resistance was influenced by different QTLs in different environments. Based on the results of the genomic prediction models and GWAS, scald resistance seems to be a quantitative trait controlled by many minor QTL and one major QTL, and to be influenced by genotype-by-environment interactions.

Effect of Defoliation Time on Rye Yield and Its Quality under Dual-Purpose Cultivation for Roughage and Concentrate Production

A dual-purpose cultivation system allows cereals to produce both roughage and concentrate during one growing season. To establish a cultivation system for rye, the appropriate time for foliage mowing was determined to ensure a yield of nutrient-rich roughage from the first crop and abundant grain from the second crop. This is because the stage of growth at defoliation affects the yield and quality of both crops. The experimental rye line ‘4R-504’ was grown in two successive cropping seasons; 2019/2020 and 2020/2021. Foliage was mowed at three different growth stages: the booting stage (BT), the early-heading stage (EH), and the fully heading stage (FH). Along with the growth stage, the plants grew taller, and the highest dry matter yield in the first crop was observed in FH (757 g m−2), which was 1.5 times higher than that in BT (480 g m−2). Although the nutritional value was higher in plants harvested at an earlier growth stage, the EH and FH plants showed a higher dry matter yield, resulting in a higher production of metabolizable energy per area. Plants that had been mowed earlier regrew vigorously and produced an abundant amount of grains in the second crop. BT showed the highest grain yield of 239 g m−2, which corresponds to 60% of the yield from the unmowed control. FH produced grains of only 76 g m−2, which barely met the requirement of the dual-purpose cropping system. To enhance the nutritional yield of roughage, it is recommended to harvest the first crop at the early heading stage. Conversely, to achieve a higher grain yield, defoliation should be carried out during the booting stage.

Breeding allelopathy in cereal rye for weed suppression

AbstractRapid increase in the hectarage and agricultural systems that use cover cropping for soil conservation and improvement, soil moisture retention, and weed management has highlighted the need to develop formal breeding programs for cover crop species. Cereal rye (Secale cereale L.) is preferred by many growers due to high biomass production and weed-suppression potential, which is believed to be partially due to allelopathy. Rye germplasm exhibits large variability in allelopathic activity, which could be used to breed rye with enhanced weed suppression. Here, we provide an overview of rye history and breeding and describe a strategy to develop rye lines with increased allelopathic activity. The discussion focuses on ways to deal with important challenges to achieving this goal, including obligate cross-pollination and its consequent high segregation levels and the need to quantify allelopathic activity under field conditions. This review seeks to encourage weed scientists to collaborate with plant breeders and promote the development of cover crop cultivars better suited to reduce weed populations.

Prediction of additive, epistatic, and dominance effects using models accounting for incomplete inbreeding in parental lines of hybrid rye and sugar beet.

Genomic models for prediction of additive and non-additive effects within and across different heterotic groups are lacking for breeding of hybrid crops. In this study, genomic prediction models accounting for incomplete inbreeding in parental lines from two different heterotic groups were developed and evaluated. The models can be used for prediction of general combining ability (GCA) of parental lines from each heterotic group as well as specific combining ability (SCA) of all realized and potential crosses. Here, GCA was estimated as the sum of additive genetic effects and within-group epistasis due to high degree of inbreeding in parental lines. SCA was estimated as the sum of across-group epistasis and dominance effects. Three models were compared. In model 1, it was assumed that each hybrid was produced from two completely inbred parental lines. Model 1 was extended to include three-way hybrids from parental lines with arbitrary levels of inbreeding: In model 2, parents of the three-way hybrids could have any levels of inbreeding, while the grandparents of the maternal parent were assumed completely inbred. In model 3, all parental components could have any levels of inbreeding. Data from commercial breeding programs for hybrid rye and sugar beet was used to evaluate the models. The traits grain yield and root yield were analyzed for rye and sugar beet, respectively. Additive genetic variances were larger than epistatic and dominance variances. The models' predictive abilities for total genetic value, for GCA of each parental line and for SCA were evaluated based on different cross-validation strategies. Predictive abilities were highest for total genetic values and lowest for SCA. Predictive abilities for SCA and for GCA of maternal lines were higher for model 2 and model 3 than for model 1. The implementation of the genomic prediction models in hybrid breeding programs can potentially lead to increased genetic gain in two different ways: I) by facilitating the selection of crossing parents with high GCA within heterotic groups and II) by prediction of SCA of all realized and potential combinations of parental lines to produce hybrids with high total genetic values.

Identification and characteristics of wheat Lr orthologs in three rye inbred lines.

The genetic background of the immune response of rye to leaf rust (LR), although extensively studied, is still not well understood. The recent publication of the genome of rye line Lo7 and the development of efficient transcriptomic methods has aided the search for genes that confer resistance to this disease. In this study, we investigated the potential role of rye orthologs of wheat Lr genes (Lr1, Lr10, Lr21, Lr22a, and RGA2/T10rga2-1A) in the LR seedling-stage resistance of inbred rye lines D33, D39, and L318. Bioinformatics analysis uncovered numerous Lr orthologs in the Lo7 genome, namely, 14 ScLr1, 15 ScRga2, and 2 ScLr21 paralogs, and 1 each of ScLr10 and ScLr22a genes. The paralogs of ScLr1, ScRga2, and ScLr21 were structurally different from one another and their wheat counterparts. According to an RNA sequencing analysis, only four wheat Lr gene orthologs identified in the Lo7 genome (ScLr1_3, ScLr1_4, ScLr1_8, and ScRga2_6) were differentially expressed; all four were downregulated after infection with compatible or incompatible isolates of Puccinia recondita f. sp. secalis (Prs). Using a more precise tool, RT-qPCR, we found that two genes were upregulated at 20 h post-infection, namely, ScLr1_4 and ScLr1_8 in lines D33 and D39, respectively, both of which have been found to be resistant to LR under field conditions and after treatment with a semi-compatible Prs strain. We were unable to discern any universal pattern of gene expression after Prs infection; on the contrary, all detected relationships were plant genotype-, Prs isolate-, or time-specific. Nevertheless, at least some Lr orthologs in rye (namely, ScLr1_3 ScLr1_4, ScLr1_8, and ScRga2_6), even though mainly downregulated, may play an important role in the response of rye to LR.

Expression and inheritance of performance constituents and seed color in winter rye

Purpose. To establish peculiarities of inheritance of major breeding traits in lines - parents of winter rye hybrids; to assess the effectiveness of creating starting material for heterotic winter rye breeding based on lines - donors of purple seed color and a set of valuable economic characteristics. Material and methods. The experiments were conducted in the fields of Verkhniachka Experimental Breeding Station of the Institute of Bioenergy Crops and Sugar Beet (Verkhniachka EBS IBCSB) of NAAS of Ukraine (Umanskyi District of Cherkassy Region) in 2021-2022. The following F1 and F2 simple hybrids were studied: l.471 x l.44 and l.471 x l.4351H.4-1-22. F1 hybrids were sown manually in single-row sections of 1.5 m long by wide-row method (interrow distance = 25–30 cm) to a depth of 3–4 cm in 2020. The sowing design was as follows: female form – F1 – male form, using the female and male forms as references. All fully ripened plants were harvested with roots. For structural analysis, 25 plants of the hybrids, female and male forms were taken; they were evaluated for the following morphological features: plant height (PH), the productive shoot number (PSN), and spike length (SL). We analyzed such performance constituents as the flower number per spike (FMS), kernel number per spike (KNP), kernel weight per spike (KWS), kernel weight per plant (KWP), and thousand kernel weight (TKW). During the growing period, the phases of plant growth and development were monitored. Correspondence of the observed ratio of phenotypic classes to the theoretical one in F2 was assessed by the χ2 test. Results and discussion. Various forms from a genetic collection, carriers of dominant and recessive alleles of one or several marker traits were used as the starting material to explore expression and inheritance of morphological traits. Hybrid combination No. 16/17–743/18 (line 471) with purple seeds, which had been created by selection and self-pollination (inbreeding), was crossed with donors of the dominant ‘short stem’ trait with wild-type (light) color of seeds, l.44 and l.4351H.4-1-22. In F1 hybrids, the quantitative constituents of the plant performance, in particular the productive shoot number, flower number per spike, kernel number per spike, kernel weight per spike, and kernel weight per plant were higher than the parents’ mean values. High degree of dominance indicated that these traits were inherited by dominance and overdominance. In F2 hybrids, dihybrid segregation into genotypes with different colors was observed: purple due to pigments in the caryopsis coat, intermediate and wild-type color of the aleurone layer, with greater number of wild-type plants. The purple color of the caryopsis in the parental lines, l.44 and l.4351H.4-1-22, turned out to be recessive relative to the wild-type color, but at the same time it was dominant in l.471 / l.44 relative to intermediate color, and in l.4351H.4-1-22, on the contrary, it was recessive in relation to intermediate color. Epistasis in l.471 / l.44 was seen in the following sequence: wild-type ˃ purple ˃ intermediate, while in l.471 / l.4351H.4-1-22 the sequence differed: wild-type ˃ intermediate ˃ purple. Conclusions. Regardless of the genotypes of winter rye lines with colored and wild-type seeds included in crossings, the purple color of seeds showed a monogenic recessive inheritance.

Assessment of combinational ability of inbred lines of winter rye by the topcross method

Dentification perspective on combinational ability of the inbred lines of winter rye is an important stage in hybrid breeding. The purpose of researches - to estimate the general and specific combinational ability of the inbred lines of winter rye by a method of full top crossings. As a maternal form 30 homozygous lines of rye bearing sterile cytoplasm Pampas type served. As testers 4 male fertile homozygous lines used : mfН-1432, mfН-1423, mfН-1147 and mfН-1842. Test crossings carried out in 2019 on spatially the isolated plots. In total 120 simple interlinear hybrids of F1 were received. Their test carried out in 2020 on plots 8,0 m2 in 2 repetitions at norm of seeding of 500 grains on 1 m2. As the standard used population variety Valdai. Productivity of hybrids F1 varied from 5,08 to 7,55 t/hectare at average productivity in experience 6,27t/hectare. Hybrids with participation of the line msH-1185-1 were the most yielding. Their productivity varied from 6,92 to 7,48 t/hectare depending on a tester. Frequency of hybrids of F1 with authentically high competitive heterosis made 20 of 120 or 16,7 %. In dispersion of a sign of productivity the essential contribution was made both the general (GCA), and specific (SCA) combinational ability. However fell to the share of effects GCA 91,2 % of all dispersion of productivity, and to SCA share - 6,9 %. The high relation variances by GCA/SCA is pointed to rather high genetic divergence by the inbred lines taken for crossing. Authentically high GCA showed 7 sterile lines: ms H-1185-1, msH-1185-2, msН-1179, msН-1238, msН-700, msН-48, msН-1247. Among lines testers of the best on GCA there was mfН-1147. High effects of SCA showed the msН-451, msН-577, msН-842, msH-1185-2 and msН-1190 lines, and also testers of mfН-1432 and mfН-1423. It is characteristic that average productivity of hybrids with participation of lines with high GCA was authentically above, than average productivity of hybrids with participation of lines from high SCA (6,76 t/hectare against 6,24 t/hectare, tfact=3,38> t05=2,22). Significantly low GCA possessed 9 sterile lines. Positive correlation between effects of GCA lines and level of their own productivity is revealed (r=0,59, t fact =2,30> t 05=2,22)

Variation between glaucous and non-glaucous near-isogenic lines of rye (Secale cereale L.) under drought stress

Glaucous (811, L35, and RXL10) and non-glaucous (811bw, L35bw, and RXL10bw) near-isogenic lines (NILs) of rye (Secale cereale L.) forming three pairs of inbred lines were the subject of the research. The research aimed to study the relationship between wax cover attributes and the physio-biochemical drought reactions and yield of rye NILs and to uncover the differences in drought resistance levels of these lines. The greatest differences between glaucous and non-glaucous NILs were observed in the RXL10/RXL10bw pair. Of particular note were the stable grain number and the thousand grain weight of the non-glaucous line RXL10bw under drought and the accompanying reactions, such as an approximately 60% increase in MDA and a two-fold increase in wax amount, both of which were significantly higher than in the glaucous line RXL10 and in other NILs. The surprisingly high level of MDA in the RXL10bw line requires further analysis. Moreover, additional wax crystal aggregates were found under drought conditions on the abaxial leaf surface of the glaucous lines 811 and RXL10. The use of rye NILs indicated that line-specific drought resistance could be associated with wax biosynthetic pathways involved in physiological and biochemical responses important for increased drought resistance.

ОСОБЛИВОСТІ РЕАКЦІЇ ПОТЕНЦІАЛУ ПРОДУКТИВНОСТІ ГІБРИБІВ ЖИТА ОЗИМОГО (SECALE CEREALE L.) НА АГРОКЛІМАТИЧНІ УМОВИ ЦЕНТРАЛЬНОГО ЛІСОСТЕПУ УКРАЇНИ

Topicality. Adaptive properties and the plant resistance to adverse environmental factors greatly influence obtaining a high and stable yield, especially in adverse and extreme weather conditions. Issues. The introduction of modern Ukrainian varieties of winter rye with high adaptive properties makes it possible to solve the problem of stabilization of grain yield and production. Aim. To determine the adaptive potential of the best cytoplasmic male sterile hybrids in the environmental variety testing system. Material and methods. The initial material for research was varieties, hybrids and lines of winter rye with recessive control of stem length, donors of self-fertility and cytoplasmic male sterility from the collection of the Verkhniachka Research and Breeding Station at the Institute of Bioenergy Crops and Sugar Beets NAAS Ukraine. We have performed the research according to generally accepted methods. The response degree of genotypes to the variability of environmental conditions and the breeding value of hybrids were characterized by the coefficient of ecological plasticity b1. Results.The influence of climatic conditions on the winter rye yield was studied and the assessment of ecological plasticity and stability of hybrids was given. Based on the results of research, it is possible to recommend for cultivation of winter rye hybrids which give a stable yield regardless of weather conditions and with regression coefficient of not less than 1.0 and a minimum mean deviation from the regression line. Conclusions. During 2015–2019, approbation of hybrids was carried out in 8 regional State centers for plant variety examination of Ukraine. According to the results of the State Scientific and Technical Examination, Wals hybrid was included in the State Register of Plant Varieties Suitable for Spreading in Ukraine since 2020 and was recommended for cultivation in the Forest-Steppe zone of Ukraine. Key words: winter rye, hybrid, growing environment, ecological plasticity, yield.

Repression of Mitochondrial Citrate Synthase Genes by Aluminum Stress in Roots of Secale cereale and Brachypodium distachyon.

Aluminum (Al) toxicity in acid soils influences plant development and yield. Almost 50% of arable land is acidic. Plants have evolved a variety of tolerance mechanisms for Al. In response to the presence of Al, various species exudate citrate from their roots. Rye (Secale cereale L.) secretes both citrate and malate, making it one of the most Al-tolerant cereal crops. However, no research has been done on the role of the mitochondrial citrate synthase (mCS) gene in Al-induced stress in the rye. We have isolated an mCS gene, encoding a mitochondrial CS isozyme, in two S. cereale cultivars (Al-tolerant cv. Ailés and Al-sensitive inbred rye line Riodeva; ScCS4 gene) and in two Brachypodium distachyon lines (Al-tolerant ABR8 line and Al-sensitive ABR1 line; BdCS4 gene). Both mCS4 genes have 19 exons and 18 introns. The ScCS4 gene was located on the 6RL rye chromosome arm. Phylogenetic studies using cDNA and protein sequences have shown that the ScCS4 gene and their ScCS protein are orthologous to mCS genes and CS proteins of different Poaceae plants. Expression studies of the ScCS4 and BdSC4 genes show that the amount of their corresponding mRNAs in the roots is higher than that in the leaves and that the amounts of mRNAs in plants treated and not treated with Al were higher in the Al-tolerant lines than that in the Al-sensitive lines of both species. In addition, the levels of ScCS4 and BdCS4 mRNAs were reduced in response to Al (repressive behavior) in the roots of the tolerant and sensitive lines of S. cereale and B. distachyon.

Lodging resistance and feeding quality of triticale and cereal rye lines in an alpine pastoral area of P. R. China

AbstractTriticale (× Triticosecale Wittmack) is a hybrid progeny of wheat (Triticum spp.) and rye (Secale cereale L.) and exhibits significant heterosis compared with its parents. Triticale is grown in many countries as a forage crop and has broad application prospects. In this study, conducted in 2015 and 2016 at Gansu, P. R. China, the morphological characteristics of stems, the microstructural features of the second internode from the base, and the chemical components of two triticale lines and two rye lines were compared. This study found that the plant height of triticale was lower than that of rye (P < .01), whereas the triticale internode diameter was larger (P < .05). Compared with values in rye, the diameter of the second internode from the base, thickness of the stem wall, ratio of the length of the second internode to the total length, and the sheath/internode weight ratio were all greater in triticale. Examination of the anatomical structure of the second internode revealed that the basic and vascular tissues of stems of triticale were more developed than those of rye. In addition, cellulose, lignin, neutral detergent fiber, acid detergent fiber, and ash contents of triticale stems were less than those of rye, whereas the triticale soluble sugar content was greater (p < .01). Therefore, we inferred that triticale stems have greater nutritional value, palatability, lodging resistance, and production potential than rye and were suitable for planting and popularizing in alpine pastoral areas.

Correlation between leaf epicuticular wax composition and structure, physio-biochemical traits and drought resistance in glaucous and non-glaucous near-isogenic lines of rye.

SUMMARYThe objective of this research was to investigate the differences between glaucous and non‐glaucous near‐isogenic lines (NILs) of winter rye (Secale cereale L.) in terms of epicuticular wax layer properties (weight, composition, and crystal morphology), selected physiological and biochemical responses, yield components, above‐ground biomass, and plant height under soil drought stress. An important aspect of this analysis was to examine the correlation between the above characteristics. Two different NIL pairs were tested, each consisting of a typical glaucous line and a non‐glaucous line with a recessive mutation. The drought experiment was conducted twice (2015–2016). Our study showed that wax accumulation during drought was not correlated with higher leaf hydration and glaucousness. Environmental factors had a large impact on the response of the lines to drought in individual years, both in terms of physiological and biochemical reactions, and the composition of epicuticular leaf wax. The analysed pairs displayed significantly different responses to drought. Demonstration of the correlation between the components of rye leaf wax and the physiological and biochemical parameters of rye NILs is a significant achievement of this work. Interestingly, the study showed a correlation between the wax components and the content of photosynthetic pigments and tocopherols, whose biosynthesis, similarly to the biosynthesis of wax precursors, is mainly located in chloroplasts. This suggests a relationship between wax biosynthesis and plant response to various environmental conditions and drought stress.

Early prediction of biomass in hybrid rye based on hyperspectral data surpasses genomic predictability in less-related breeding material

Key messageHyperspectral data is a promising complement to genomic data to predict biomass under scenarios of low genetic relatedness. Sufficient environmental connectivity between data used for model training and validation is required.The demand for sustainable sources of biomass is increasing worldwide. The early prediction of biomass via indirect selection of dry matter yield (DMY) based on hyperspectral and/or genomic prediction is crucial to affordably untap the potential of winter rye (Secale cereale L.) as a dual-purpose crop. However, this estimation involves multiple genetic backgrounds and genetic relatedness is a crucial factor in genomic selection (GS). To assess the prospect of prediction using reflectance data as a suitable complement to GS for biomass breeding, the influence of trait heritability (H^{2}) and genetic relatedness were compared. Models were based on genomic (GBLUP) and hyperspectral reflectance-derived (HBLUP) relationship matrices to predict DMY and other biomass-related traits such as dry matter content (DMC) and fresh matter yield (FMY). For this, 270 elite rye lines from nine interconnected bi-parental families were genotyped using a 10 k-SNP array and phenotyped as testcrosses at four locations in two years (eight environments). From 400 discrete narrow bands (410 nm–993 nm) collected by an uncrewed aerial vehicle (UAV) on two dates in each environment, 32 hyperspectral bands previously selected by Lasso were incorporated into a prediction model. HBLUP showed higher prediction abilities (0.41 – 0.61) than GBLUP (0.14 – 0.28) under a decreased genetic relationship, especially for mid-heritable traits (FMY and DMY), suggesting that HBLUP is much less affected by relatedness and H^{2}. However, the predictive power of both models was largely affected by environmental variances. Prediction abilities for DMY were further enhanced (up to 20%) by integrating both matrices and plant height into a bivariate model. Thus, data derived from high-throughput phenotyping emerges as a suitable strategy to efficiently leverage selection gains in biomass rye breeding; however, sufficient environmental connectivity is needed.

Assessing new SSR markers for utility and informativeness in genetic studies of brown rust fungi on wheat, triticale, and rye

AbstractThe aim of the present study was to validate new simple‐sequence repeat (SSR) markers and use them to assess genetic variability among 24 isolates of Puccinia triticina collected from wheat (Pt‐wheat) and triticale (Pt‐triticale), and 15 isolates of P. recondita f. sp. secalis (Prs) collected from rye. The Pt and Prs isolates were tested for virulence on a set of 35 Thatcher wheat near‐isogenic lines, eight rye lines with known resistance genes, and 53 triticale cultivars with uncharacterized leaf rust resistance. Molecular genotypes were determined using a newly developed set of 34 SSR microsatellite primer pairs. All SSR markers tested on Pt isolates successfully amplified fragments of appropriate size. When tested on the Prs isolates, 21 out of the 34 Pt SSRs amplified expected fragments. Sixteen of these 21 SSRs were polymorphic, providing for the first time microsatellite markers to study genetic variation in Prs. Based on virulence data, variation among Prs isolates was low, probably due to the small number of rye differential lines available. Much higher variation for virulence was observed within the collection of Pt isolates from wheat and triticale, and two separate groups were established with mixed host origin. Substantial genetic variation was detected among the isolates studied with the SSR markers, assuming two different models of SSR evolution (infinite alleles model and stepwise mutation model). The newly developed set of SSR markers proved their effectiveness in detecting genetic variation and should be useful in further population genetics investigations of the two pathogens.

β-1,3-Glucanases and chitinases participate in the stress-related defence mechanisms that are possibly connected with modulation of arabinogalactan proteins (AGP) required for the androgenesis initiation in rye (Secale cereale L.)

This work presents the biochemical, cytochemical and molecular studies on two groups of PR proteins, β-1,3-glucanases and chitinases, and the arabinogalactan proteins (AGP) during the early stages of androgenesis induction in two breeding lines of rye (Secale cereale L.) with different androgenic potential. The process of androgenesis was initiated by tillers pre-treatments with low temperature, mannitol and/or reduced glutathione and resulted in microspores reprogramming and formation of androgenic structures what was associated with high activity of β-1,3-glucanases and chitinases. Some isoforms of β-1,3-glucanases, namely several acidic isoforms of about 26 kDa; appeared to be anther specific. Chitinases were well represented but were less variable. RT-qPCR revealed that the cold-responsive chitinase genes Chit1 and Chit2 were expressed at a lower level in the microspores and whole anthers while the cold-responsive Glu2 and Glu3 were not active. The stress pre-treatments modifications promoted the AGP accumulation. An apparent dominance of some AGP epitopes (LM2, JIM4 and JIM14) was detected in the androgenesis-responsive rye line. An abundant JIM13 epitopes in the vesicles and inner cell walls of the microspores and in the cell walls of the anther cell layers appeared to be the most specific for embryogenesis.

Integration of genotypic, hyperspectral, and phenotypic data to improve biomass yield prediction in hybrid rye

Key messageHyperspectral and genomic data are effective predictors of biomass yield in winter rye. Variable selection procedures can improve the informativeness of reflectance data.Integrating cutting-edge technologies is imperative to sustainably breed crops for a growing global population. To predict dry matter yield (DMY) in winter rye (Secale cereale L.), we tested single-kernel models based on genomic (GBLUP) and hyperspectral reflectance-derived (HBLUP) relationship matrices, a multi-kernel model combining both matrices and a bivariate model fitted with plant height as a secondary trait. In total, 274 elite rye lines were genotyped using a 10 k-SNP array and phenotyped as testcrosses for DMY and plant height at four locations in Germany in two years (eight environments). Spectral data consisted of 400 discrete narrow bands ranging between 410 and 993 nm collected by an unmanned aerial vehicle (UAV) on two dates on each environment. To reduce data dimensionality, variable selection of bands was performed, resulting in the least absolute shrinkage and selection operator (Lasso) as the best method in terms of predictive abilities. The mean heritability of reflectance data was moderate (h^{2} = 0.72) and highly variable across the spectrum. Correlations between DMY and single bands were generally significant (p < 0.05) but low (≤ 0.29). Across environments and training set (TRN) sizes, the bivariate model showed the highest prediction abilities (0.56–0.75), followed by the multi-kernel (0.45–0.71) and single-kernel (0.33–0.61) models. With reduced TRN, HBLUP performed better than GBLUP. The HBLUP model fitted with a set of selected bands was preferred. Within and across environments, prediction abilities increased with larger TRN. Our results suggest that in the era of digital breeding, the integration of high-throughput phenotyping and genomic selection is a promising strategy to achieve superior selection gains in hybrid rye.

Molecular Analysis of the Gibberellin Signaling Pathway Genes in Cultivated Rye (Secale cereale L.)

Gibberellin signaling pathway genes encoding the DELLA protein and gibberellin receptor GID1 were sequenced in several varieties (Alpha, Valdai, Orlovskaya 9, Pracha) and one line of rye (EM-1) using next generation methods. The revealed multiple alleles of these genes differ mainly in single-nucleotide polymorphisms and less frequently in insertions and deletions. Most of the detected mutations turned out to be synonymous or located in the noncoding regions of the genes. Changes in the amino acid sequences of proteins associated with other mutations are probably functionally neutral. Mutations similar to wheat reduced-height gibberellin-insensitive alleles were not detected.

Genome‐wide association mapping and genomic prediction of Fusarium head blight resistance, heading stage and plant height in winter rye (Secale cereale)

AbstractRye is a multi‐purpose cereal crop grown in Central and Eastern Europe as well as in Western Canada. Fusarium head blight (FHB) is one of the diseases that have a severe negative impact on rye, but knowledge about FHB resistance at the genomic level is totally missing in rye. The objective of this study was to elucidate the genetic architecture of FHB resistance in winter rye using genome‐wide association (GWA) mapping complemented by genomic prediction (GP) in comparison with marker‐assisted selection (MAS). Additionally, plant height and heading stage were analysed. A panel of 465 S1‐inbred lines of winter rye was phenotyped in three environments (location–year combinations) for FHB resistance by inoculation with Fusarium culmorum and genotyped with a 15k SNP array. Significant genotypic variation and high heritabilities were found for FHB resistance, heading stage and plant height. FHB did not correlate with heading stage, but was moderately correlated with plant height (r = −.52, p &lt; .001) caused by some susceptible short inbred lines. The GWA scan identified 15 QTL for FHB resistance that jointly explained 74% of the genotypic variance. In addition, we detected 11 QTL for heading stage and 8 QTL for plant height, explaining 26% and 14% of the genotypic variance, respectively. A genome‐wide prediction approach resulted in 44% higher prediction abilities than marker‐assisted selection for FHB resistance. In conclusion, genomic approaches appear promising to improve and accelerate breeding for complex traits in winter rye.

The effect of glutathione and mannitol on androgenesis in anther and isolated microspore cultures of rye (Secale cereale L.)

Androgenic responsiveness in anther (AC) and isolated microspore cultures (MC) was analysed using 15 lines of Polish winter rye (Secale cereale L.). The effect of low temperature (LT) alone or in combination with osmotic stress induced by mannitol treatment (MAN) and/or with reduced glutathione (GSH) on the effectiveness of the process was studied. Interestingly, each treatment had a different effect on microspore (mcs) vitality and capability to divide symmetrically. The first criterion for successful embryogenesis was to exceed the threshold number of at least 25% dividing microspores, which determined ‘embryogenic suspension culture’. In some configurations a spectacular effect was achieved, especially in lines highly recalcitrant to androgenesis induction. Relatively high effectiveness of androgenesis induction (up to 4.58 AS per 105 mcs per spike in MC and 21.29 AS per spike in AC) showed that the developed protocol with GSH and/or MAN tiller pre-treatments overcomes the genotypic barrier for androgenesis initiation in rye. Moreover, relatively high, spontaneous genome diploidization (55%) of regenerated plants demonstrated that the described protocols could be effectively integrated into conventional rye breeding programmes.