Karyotype and plasmotype characteristics in wheat-rye hybrids with the different structural organization of the nuclear genome

Aim. Genome structure analysis and plasmotype identification in wheat-rye hybrids of various types (triti- cale, secalotriticum) and ploidy level. Mcth0ds. Cytological and molecular-genetic analysis. Rcsults. The karyotype and plasmotype analysis was carried out in 11 stable lines of secondary recombinant hexaploid triticale with the introgression of D-genome chromosomes of the wheat (A/B/DRR, 2n = 6x = 42), 14 stable and highly productive secalotriticum lines of F6–16 generations (Secalotriticum, S/RRAABB, 2n = 6x = 42), 9 stable lines of tetraploid triticale (A/BRR, 2n = 4x = 28). By means of differential chromosome staining, the chromosomal composition of the experimental material was characterized and the intergenomic substitution and translocation of chromosomes were detected. The PCR-RFLP analysis of the 18S/5S mitochondrial (mt) repeat and the ndhH-region of chloroplast DNA showed that these organ- elle DNA regions are in the homoplasmic state and belong to rye-type cytoplasm in secalotriticum lines and wheat-type cytoplasm in tetraploid and secondary recombinant hexaploid triticale lines. C0nclusi0ns. Cytological and molecular genetic analysis revealed significant genetic diversity of the created gene pool of wheat-rye hybrids by nuclear-cytoplasmic structure. The synthesized linear material of wheat-rye hybrids may be used in cytogenetic research and practical breeding.

Evaluation of valuable agronomic traits of spring triticale in a long-term breeding trial

The analysis of data of long-term breeding trials of spring hexaploid triticale, used for forage and grains, was carried out using mathematical methods and developed software. The valuable agronomic traits of the ideal variety have been determined. The possibility of purposeful breeding for adaptability to the conditions of the region when creating new high-yielding varieties is shown.

Fine Mapping and Distribution Analysis of Hybrid Necrosis Genes Ne1 and Ne2 in Wheat in China

Hybrid necrosis of wheat is caused by two dominant complementary genes Ne1 and Ne2 present in normal phenotype parents and is regarded as a barrier to gene flow between crop species. However, the necrosis alleles still occur at high frequency in modern wheat varieties. In this study, we constructed two high-density genetic maps of Ne1 and Ne2 in winter wheat. In these cultivars, Ne1 was found to be located in a span interval of 0.50 centimorgan (cM) on chromosome 5BL delimited by markers Nwu_5B_4137 and Nwu_5B_5114, while Ne2 co-segregated with markers Lseq102 and TC67744 on 2BS. Statistical analysis confirmed that the dosage effect of Ne alleles also existed in moderate and severe hybrid necrosis systems, and the symptoms of necrosis can also be affected by the genetic background. Furthermore, we clarified the discrete distribution and proportion of the Ne1 and Ne2 in China’s major wheat regions, and concluded that introduced modern cultivars directly affect the frequencies of necrosis genes in modern Chinese cultivars (lines), especially that of Ne2. Taking investigations in spring wheat together, we proposed that hybrid necrosis alleles could positively affect breeding owing to their linked excellent genes. Additionally, based on the pedigree, we speculated that the Ne1 and Ne2 in winter wheat may directly originate from wild emmer and introduced cultivars or hexaploid triticale, respectively.

Genotyping-by-sequencing and genome-wide association study reveal genetic diversity and loci controlling agronomic traits in triticale

Key message The genetic diversity and loci underlying agronomic traits were analysed by the reads coverage and genome-wide association study based genotyping-by-sequencing in a diverse population consisting of 199 accessions.Abstract Triticale (×Triticosecale Wittmack) is an economically important grain-forage and energy crop planted worldwide for its high biomass. Little is known about the genetic diversity and loci underlying agronomic traits in triticale. We performed genotyping-by-sequencing of 199 cultivars and mapped reads to the A, B, D, and R genomes for karyotype analysis. These cultivars could mostly be grouped into five types. Some chromosome abnormalities occurred with high frequency, such as 2D (2R) substitution, deletion of the long arm of chromosome 2D or the short arm of 5R, and translocation of the long arms of 7D/7A, the short arms of 6D/6A, or the long arms of 1D/1A. We chose only widely planted hexaploid triticale cultivars (153) for genome-wide association study. These cultivars could be divided into nine distinct groups, and the linkage disequilibrium decay was 25.4 kb in this population. We identified 253 significant marker-trait associations (MTAs) on 20 chromosomes, except 7R. Twenty-one reliable MTAs were identified repeatedly over two environments. We predicted 16 putative candidate genes involved in plant growth and development using the genome sequences of wheat and rye. These results provide a basis for understanding the genetic mechanisms of agronomic traits and will benefit the breeding of improved hexaploid triticale.

Breeding of highly productive varieties of winter triticale resistant to pre-harvest germination of grain in the ear

Creation of new varieties of winter hexaploid triticale for the central part of Russia is characterized by increased resistance of grain to germination on the root. The phenomenon of germination on the root is one of the limiting traits that limit the spread of triticale culture in areas of excessive moisture, which is the Central Region of the Non-Chernozem zone. The work was carried out at the Russian State Agrarian University – Moscow Agricultural Academy named after K.A. Timiryazev in 2018-2019. Field experiments were conducted in the fields of the Field Experimental and Breeding Stations. Laboratory tests were carried out at the Department of Genetics, Breeding and Seed Production. As a result of a comprehensive assessment of breeding varieties in the preliminary variety testing, the most valuable sample of winter triticale 228h (Castus x Don) was isolated, which formed a yield at the standard level, and during 3 years of study showed relatively high resistance to pre-harvest germination of grain in the ear. This sample is currently being intensively propagated for transfer to the State Variety Testing in 2020.

Efficiency of using indexes method in the comprehensive assessment of the genetic collection in the winter hexaploid triticale

The paper presents the comparative assessment results of 53 collection samples of winter hexaploid triticale of various ecological and geographical origin using traditional statistical methods and methods of complex indices (Jk), perspectivity indices (Jp), ecological plasticity (Jsp), Finno-Scandinavian (FSJ), Mexican (Mi), and adaptive potential. By the traditional statistical method, high-yield varieties with high values of individual elements of plant productivity were identified: (k-3717) Kaskad, (k-4071) Ramzay, (k-3969) Trizub, (k-3924) Popsuevskaya, (k-3900) Prometey, (k-4095) Shalanda, (k-4097) Buket. The following varieties were identified by the method of complex indices: (k-3909) Topaz, (k-3717) Kaskad, (k-3931) Skif, (k-4071) Ramzay, (k-3969) Trizub, (k-4074) Valentin-90, (k-4078) Bordo, (k-3924), Popsuevskaya, (k-3968) Interes, (k-3901) Mars, (k-3900) Prometey, (k-4003) Disko, (k-3999) Anvo, (k-3701) Fidelio, (k-4095) Shalanda, (k-4097) Buket. According to the indices’ complex that determine the prospects of the variety, the grain-forming ability of its ear, resistance to lodging, high adaptive potential, the following varieties were identified: (k-3909) Topaz, (k-3717) Kaskad, (k-4020) Zavet, (k-3932) Skolot, (k-4071) Ramzay, (k-4074) Valentin-90, (k-4076) Knyaz, (k-3924), Popsuevskaya, (k-3968) Interes, (k-3966) Ajax, (3965) Pshenichne, (k-3900) Prometey, (k-4003) Disko, (k-4005) Korvetta, (k-3999) Anvo, (k-3701) Fidelio, (k-4095) Shalanda, (k-4097) Buket, (k-3562) Antey, (k-3582) Patriot. The study results allow to speak about the usage efficiency of the indices method for a comprehensive winter triticale assessment.

Yield, plasticity and resilience of winter triticale in the conditions of the Moscow region

The aim of the work was to assess the varieties of winter hexaploid triticale in terms of yield, plasticity and stability in the central region of the Non-Black Earth Zone of the Russian Federation. Field research using the methodology of the State Sort Network was carried out on the experimental field of the Department of Genetics, Biotechnology, Breeding and Seed Production of the P.I. Lisitsyn RGAU-Moscow Agricultural Academy named after K.A. Timiryazev in 2014-2017 The linear regression coefficient (bi) was used for the estimation. As a result of the study of 43 varieties, lines and hybrids from the collection of the Department of Genetics, Breeding and Seed Production of the Russian State Agrarian University-Moscow Agricultural Academy named after K.A. Timiryazev, 6 samples of winter triticale with high genetic plasticity (Hermes, Kaskad, PRAG 468, PRAG 509, PRAG 152, hybrid PRAG 531 x PRAG 473) and 10 samples with high stability (Vocalise, Linii 19, Bard, KNIISKh 32 , Tornado, Hewo, Flamingo, Dubrava, Timbo and Legion), which can be further used to create varieties for various levels of agricultural technology.

SELECTIVELY VALUABLE TRAITS CORRELATIONS IN HEXAPLOID TRITICALE

In the article, a study of the conjugation of grain triticale selection-valuable traits was carried out in order to distinguish among them the samples that combine resistance to lodging with a number of other selection-valuable traits. According to the correlation analysis, we can say that selection-valuable traits (both productivity and resistance to fungal diseases) in most cases are positively associated with plant height and the length of the last internode. Therefore, it is necessary to search for sources of short-stemming, the expression of which does not worsen the manifestation of selectively valuable traits. In addition, it is important to select forms with a long ear culm segment. According to the correlation analysis carried out, selectively valuable traits (both productivity and resistance to fungal diseases) in most cases are positively associated with plant height. In this regard, it is necessary to search for sources of short-stemming, the expression of which does not worsen the manifestation of selectively valuable traits. Specimens with the optimal architectonics of the plant morphotype, capable of maximally mobilizing nutrients for a high yield of reproductive mass (grain) in comparison with vegetative (straw), are especially promising. A sign of productivity, the mass of grain per spike positively correlates with the mass of 1000 grains, the number of grains per spike, grain completeness and resistance to fungal diseases, and negatively with the grain size. The coarseness correlates positively with the weight of the ear, the weight of the grain and the completeness of the grain, and negatively with the percentage of the weight of the ear from the stem.

CHARACTERIZATION OF SELECTIVELY VALUABLE TRAITS OF HEXAPLOID TRITICALE VARIOUS MORPHOTYPES

The article studies triticale samples from the VIR world collection by morphological characteristics and identifies among them those combining economically valuable characteristics. When selecting the material, we adhered to the principle of sampling from a wide variety of the most typical representatives. All studied forms have 42 chromosomes in the genome. According to their lifestyle, they are subdivided into winter crops (29 samples) and spring crops (27 samples). According to the presence of a complete or partial set of rye chromosomes in the genome, triticale are grouped into typical (RR) – 43 in total and substituted "R" by "D" (R/D) – 13. Information on the origin of the studied samples is given in Table 1. The most significant material represented by triticale samples obtained at the VIR Dagestan experimental station and from Mexico. Almost all triticale from Russia and European countries are winter crops; those from Mexican and other American countries are spring crops. The study of hexaploid triticale selectively valuable traits showed that R/D substituted forms have better indicators compared to the triticale with a complete rye genome (RR) in the following traits: 1000 grain weight, grain fullness, grain size and lodging resistance. For the rest of the studied traits (stem weight with spike, spike weight, grain weight per spike, number of grains per spike, and resistance to fungal diseases), the RR of triticale exceeds the R/D substituted forms. However, it should be noted that by such traits as the weight of the ear and the weight of the grain from one ear, their percentage to the weight of the whole plant is higher in R/D triticale.

Analysis of the intralinear polymorphism and the homozygosity rate of triticale doubled haploid lines by microsatellite markers

We evaluated the rate of polymorphism of doubled haploid lines of hexaploid triticale obtained by the method of anther culture based on hybrids of spring and winter types. Using 7 SSR markers for the loci on the chromosomes A- (Xgwm186, Xgwm291, Xgwm595) and B- (Xgwm371, Xgwm540, Xgwm554, Xgwm234), polymorphism of 38 doubled haploid lines of hexaploid triticale was studied. Interlinear polymorphism along six microsatellite loci except the Xgwm554 locus, which is not polymorphic in the studied doubled haploid lines, was revealed. The highest polymorphism was observed for the Xgwm186, Xgwm291 and Xgwm595 loci. The cluster analysis showed that all studied lines were divided into three main groups. The origin of the lines did not affect the distribution in groups. This confirms the influence of in vitro culture somaclonal variation. Eight lines of doubled haploids, which are heterozygous for one of the studied microsatellite loci, were identified. We showed the possibility of using SSR markers to assess interlinear polymorphism and the homozygosity rate in the triticale doubled haploid lines obtained by the method of induced androgenesis in vitro.