Genetic Features of Triticale–Wheat Hybrids with Vaviloid-Type Spike Branching

Vaviloid spike branching, also called sham ramification, is a typical trait of Triticum vavilovii Jakubz. and is characterized by a lengthening of the spikelet axis. In this article, we present the results of a study of three triticale–wheat hybrid lines with differences in terms of the manifestation of the vaviloid spike branching. Lines were obtained by crossing triticale with hexaploid wheat, T. aestivum var. velutinum. The parental triticale is a hybrid of synthetic wheat (T. durum × Ae. tauschii var. meyrei) with rye, S. cereale ssp. segetale. Line 857 has a karyotype corresponding to hexaploid wheat and has a spike morphology closest to normal, whereas Lines 808/1 and 844/4 are characterized by the greatest manifestation of vaviloid spike branching. In Lines 808/1 and 844/4, we found the substitution 2RL(2DL). The karyotypes of the latter lines differ in that a pair of telocentric chromosomes 2DS is detected in Line 808/1, and these telocentrics are fused into one unpaired chromosome in Line 844/4. Using molecular genetic analysis, we found a deletion of the wheat domestication gene Q located on 5AL in the three studied hybrid lines. The deletion is local since an analysis of the adjacent gene B1 showed the presence of this gene. We assume that the manifestation of vaviloid spike branching in two lines (808/1 and 844/4) is associated with a disturbance in the joint action of genes Q and AP2L2-2D, which is another important gene that determines spike morphology and is located on 2DL.

Development of haploids in the winter bread wheat anthers

In the modern world, the use of isolated anther cultivation technology is currently an integral part of the wheat breeding process. The development of haploids in the winter bread wheat anthers will allow obtaining new forms of wheat in the shortest possible time and without large areas. The purpose of the current study was to estimate the F3 winter bread wheat hybrids according to the anthers’ sensitivity to androgenesis and plant regeneration in vitro and to identify the factors affecting the yield of haploid production. There has been studied the ability to androgenesis in vitro in the anthers of four winter bread wheat hybrids of intensive and semi-intensive type of the FSBSI “ARC “Donskoy”. There has been assessed the role of the mineral composition of three induction nutrient media N6, W14 and NPB-99. There has been established a correlation between the main stages of development of haploids and a genotype. The highest regeneration rate of green plants was obtained in the sample F3 623 of intensive type (3.3%). The most suitable medium for androgenesis of the winter bread wheat anthers in vitro is NPB-99. Since the genotype F3 623 of intensive type demonstrated high values of haploid production capacity, it could be successfully used in breeding programs for the rapid production of homozygous wheat anther lines in vitro. Using two-way analysis of variance, there has been identified a correlation between the effects of a genotype, nutrient medium and their interaction with the main parameters of haploid formation in winter wheat. The formation of embryogenic structures is mainly associated with the effect of a genotype (46.52%). The proportion of the nutrient composition of the medium was low (1.82%), and the correlation factor was 2.1%. The genotype had the greatest effect on the indicator of the regenerants’ number. The nutrient medium had little effect. Regarding the regeneration of green plants, which is the main indicator of the haploid production, the share of a genotype effect was the largest (47.32%). The contribution of the medium and the correlation of factors were less important, but statistically significant.

Starting material for breeding spring emmer (Triticum dicoccum shrank.) of groats use

Aim. To explore sources of high groats properties among the genetic diversity of emmer and related species. Methods. Biochemical: The protein content was determined by Kjeldahl digestion; the starch content – by infrared spectroscopy. Technological: the vitreousness was determined by cutting 100 caryopses and expressed as percent- ages. The hull content, expressed in percent, was estimated as the ratio of hulled caryopses to the total of fully threshed ones. The gluten content and quality were assessed by manual washing-out. The hardness was determined on a YPD-300 hardness tester (Ltpm China) as the force in newtons required for caryopsis destruction. Emmer groats were obtained on a laboratory peeler UShZ-1. The groats properties were evaluated according to the method described in a utility model patent No. 129205. Statistical: the significance of differences between accessions was assessed using the Mann-Whitney test for small samples with unknown distribution. Two-factor analysis of vari- ance considered 2 factors – genotype and year conditions. Pearson’s test was used in the correlation analysis. The variability of traits was assessed by the coefficient of variation (CV). Results. The yields of emmer and durum wheat accessions and varieties as well as lines derived from emmer-wheat hybrids were measured and analyzed in 2016–2019. The yields of most emmer accessions (except for T. timopheevii) were similar to that of the check em- mer variety Holikovska (286 ± 15 g/m2). The highest contents of protein and gluten were found in T. timopheevii (18.1 ± 0.4 % and 40.5 ± 1.8 %, respectively), Triticum durum Desf. var. falcatomelanopus Jakubz. & Filat. (17.5 ± ± 1.0 % and 40.4 ± 1.4 %), autochthonous variety Polba 3 (16.8 ± 0.1 % and 36.9 ± 1.1 %), and line 10–139 (14.8 ± 0.8 % and 29.0 ± 2.4 %). The gluten quality of most lines, derived from crossing spring emmer with durum wheat, corresponds to quality group I (good), and the gluten deformation index (GDI) is 50–75 units. T. timopheevii and T. durum var. falcatomelanopus were noticeable for vitreousness (99 ± 1 % and 75 ± 5 %, respec- tively). The grain hardness of the accessions under investigation varied from 151 ± 15 N in variety Romanivska to 286 ± ± 3 N in T. timopheevii. Lines 10–79 (255 ± 6 N), 10–65 (220 ± 10 N) and T. durum var. falcatomelanopus (268 ± 6 N) were characterized by high hardness, which exceeded that of durum wheat variety Spadshchyna (152 ± ± 13 N). High outputs of groats were intrinsic to line 10–139 (96.2 ± 0.8 %), line 10–79 (90.6 ± 0.8 %), T. timopheevii (92.0 ± 0.1 %), and durum wheat Spadshchyna (91.4 ± 0.5 %). All the studied accessions showed low variability (

Starting material for breeding spring emmer (Triticum dicoccum shrank.) of groats use

Aim. To explore sources of high groats properties among the genetic diversity of emmer and related species. Methods. Biochemical: The protein content was determined by Kjeldahl digestion; the starch content – by infrared spectroscopy. Technological: the vitreousness was determined by cutting 100 caryopses and expressed as percent- ages. The hull content, expressed in percent, was estimated as the ratio of hulled caryopses to the total of fully threshed ones. The gluten content and quality were assessed by manual washing-out. The hardness was determined on a YPD-300 hardness tester (Ltpm China) as the force in newtons required for caryopsis destruction. Emmer groats were obtained on a laboratory peeler UShZ-1. The groats properties were evaluated according to the method described in a utility model patent No. 129205. Statistical: the significance of differences between accessions was assessed using the Mann-Whitney test for small samples with unknown distribution. Two-factor analysis of vari- ance considered 2 factors – genotype and year conditions. Pearson’s test was used in the correlation analysis. The variability of traits was assessed by the coefficient of variation (CV). Results. The yields of emmer and durum wheat accessions and varieties as well as lines derived from emmer-wheat hybrids were measured and analyzed in 2016–2019. The yields of most emmer accessions (except for T. timopheevii) were similar to that of the check em- mer variety Holikovska (286 ± 15 g/m2). The highest contents of protein and gluten were found in T. timopheevii (18.1 ± 0.4 % and 40.5 ± 1.8 %, respectively), Triticum durum Desf. var. falcatomelanopus Jakubz. & Filat. (17.5 ± ± 1.0 % and 40.4 ± 1.4 %), autochthonous variety Polba 3 (16.8 ± 0.1 % and 36.9 ± 1.1 %), and line 10–139 (14.8 ± 0.8 % and 29.0 ± 2.4 %). The gluten quality of most lines, derived from crossing spring emmer with durum wheat, corresponds to quality group I (good), and the gluten deformation index (GDI) is 50–75 units. T. timopheevii and T. durum var. falcatomelanopus were noticeable for vitreousness (99 ± 1 % and 75 ± 5 %, respec- tively). The grain hardness of the accessions under investigation varied from 151 ± 15 N in variety Romanivska to 286 ± ± 3 N in T. timopheevii. Lines 10–79 (255 ± 6 N), 10–65 (220 ± 10 N) and T. durum var. falcatomelanopus (268 ± 6 N) were characterized by high hardness, which exceeded that of durum wheat variety Spadshchyna (152 ± ± 13 N). High outputs of groats were intrinsic to line 10–139 (96.2 ± 0.8 %), line 10–79 (90.6 ± 0.8 %), T. timopheevii (92.0 ± 0.1 %), and durum wheat Spadshchyna (91.4 ± 0.5 %). All the studied accessions showed low variability (

Dissecting Bread Wheat Heterosis through the Integration of Agronomic and Physiological Traits

To meet the challenge of feeding almost 10 billion people by 2050, wheat yield has to double by 2050. However, over the past 20 years, yield increase has slowed down and even stagnated in the main producing countries. Following the example of maize, hybrids have been suggested as a solution to overcome yield stagnation in wheat. However, wheat heterosis is still limited and poorly understood. Gaining a better understanding of hybrid vigor holds the key to breed for better varieties. To this aim, we have developed and phenotyped for physiological and agronomic traits an incomplete factorial design consisting of 91 hybrids and their nineteen female and sixteen male parents. Monitoring the plant development with normalized difference vegetation index revealed that 89% of the hybrids including the five higher yielding hybrids had a longer grain filling phase with a delayed senescence that results in larger grain size. This average increase of 7.7% in thousand kernel weight translated to a positive mid-parent heterosis for grain yield for 86% of hybrids. In addition, hybrids displayed a positive grain protein deviation leading to a +4.7% heterosis in protein yield. These results shed light on the physiological bases underlying yield heterosis in wheat, paving new ways to breed for better wheat hybrids.

Caracterization of Am –A genomes chromosomes in diploid wheat, polyploid wheat and triticales by marker cytogenetic

The distribution and Caracterization of constitutive heterochromatin in A-Am genomes of diploid wheat (progenitor), polyploid wheat (hybrids) and triticales (primary and secondary) are analyzed and compared by C-bands. The Comparison of zones rich in highly repeated DNA sequences marked by C bands on the all chromosomes of Am - A genomes revealed an important structural heterogeneity. Four chromosomes of Triticum monococcum (1Am-3Am-4Am-5Am) are almost similar to their homologues in wheat (Triticum durum , Triticum aestivum ) and triticale, by the presence or absence of C bands. Contrary to the chromosomes 2Am (rich in heterochromatin), 6Am-7Am (absence of C bands) show a great differentiation compared to their homologues of Triticum durum and Triticum aestivum and x-Triticosecale Wittmack. In the triticales, A genome chromosomes are richer in heterochromatin compared to theirs homologous of polyploid wheats. This is explained by a "genome shock The confrontation of C- bands genome (Triticum monococcum) with a C+ bands genome (durum wheat / or common wheat) produces an interspecific hybrid which at the sixth generation reveals C+ bands (triticales). The variations observed in our vegetal material indicated the existence of an intervarietal and interspecific heterochromatic polymorphism. The presence of B chromosomes in triticales, could be explained as a manifestation of their adaptation.

Chromosome Stability of Synthetic-Natural Wheat Hybrids

Primary allopolyploids are not only ideal materials to study species evolution, but also important bridges in incorporating genetic diversity of wild species into crops. Primary allopolyploids typically exhibit chromosome instability that a disadvantage trait in crop breeding. Newly synthesized hexaploid wheat has been widely used in wheat genetics and breeding studies. To better understand the cytological and genetic basis of chromosome instability, this study investigated the chromosomes of a large number of seeds derived from the synthetic wheat SHW-L1 and its hybrids with natural wheat. SHW-L1 exhibited persistent chromosome instability since we observed a high frequent chromosome variation de novo generated from euploid SHW-L1 plants at the 14th generation of selfing (F14). High frequent chromosome variations were also observed in the F2 hybrids and most of the analyzed recombinant inbred lines (RILs) at F14, derived from the cross of SHW-L1 with common wheat variety Chuanmai 32. Chromosome instability was associated with frequent univalency during meiotic metaphase I. The experiment on reciprocal crosses between SHW-L1 and Chuanmai 32 indicated that cytoplasm has not obvious effects on chromosome instability. An analysis on 48 F14 RILs revealed chromosome variation frequency was not associated with the Ph1 alleles from either SHW-L1 or Chuanmai 32, rejecting the hypothesis that chromosome instability was due to the Ph1 role of synthetic wheat. In the analyzed RILs, chromosome instability influences the phenotype uniformity, showing as obvious trait differences among plants within a RIL. However, the analyzed commercial varieties only containing ∼12.5% genomic components of synthetic wheat were chromosomally stable, indicating that chromosome instability caused by synthetic wheat can be effectively overcome by increasing the genetic background of common wheat.

Fine Mapping of Hybrid Necrosis Gene Ne1 in Common Wheat (Triticum Aestivum L.)

Hybrid necrosis is characterized as progressive chlorosis and necrosis of plant leaves, tillers or whole plants premature death in certain wheat hybrids, which is caused by the combination of two complementary loci Ne1 and Ne2 located on chromosome arms 5BL and 2BS, respectively. Hybrid necrosis s is a serious barrier for combining desirable traits from various genotypes of wheat and the full utilization of heterosis in wheat. In this study, we fine mapped Ne1 on chromosome 5BL, and finally delimited Ne1 to a 4.06-Mb region with large heterogeneous inbred families (HIFs) from the RILs of ‘Zhengnong 17’ × ‘Yangbaimai’. Further characterization of the near isogenic lines derived from HIFs confirmed that Ne1 was tightly linked with a 2.89-Mb fragment that is deleted in Zhengnong 17. Additionally, a diagnostic InDel marker 5B-InDel385 for Ne1 was developed and was used to assess the existence of Ne1 in a diverse panel of 501 wheat accessions. Among them, 122 (61%) out of 200 landraces showed the presence of Ne1 gene, whereas only 79 (26%) out of 301 modern cultivars carried the Ne1 gene. The drastic decrease of Ne1 frequency in modern cultivars indicates that the Ne1 has been subjected to heavily selection pressure. This study provides a good foundation for the marker-assisted selection, gene cloning and functional studies of Ne1 in wheat.