Molecular Analysis Uncovers the Mechanism of Fertility Restoration in Temperature-Sensitive Polima Cytoplasmic Male-Sterile Brassica napus

Temperature-sensitive male sterility is a heritable agronomic trait affected by genotype-environment interactions. In rapeseed (Brassica napus), Polima (pol) temperature-sensitive cytoplasmic male sterility (TCMS) is commonly used for two-line breeding, as the fertility of pol TCMS lines can be partially restored at certain temperatures. However, little is known about the underlying molecular mechanism that controls fertility restoration. Therefore, we aimed to investigate the fertility conversion mechanism of the pol TCMS line at two different ambient temperatures (16 °C and 25 °C). Our results showed that the anthers developed and produced vigorous pollen at 16 °C but not at 25 °C. In addition, we identified a novel co-transcript of orf224-atp6 in the mitochondria that might lead to fertility conversion of the pol TCMS line. RNA-seq analysis showed that 1637 genes were significantly differentially expressed in the fertile flowers of 596-L when compared to the sterile flower of 1318 and 596-H. Detailed analysis revealed that differentially expressed genes were involved in temperature response, ROS accumulation, anther development, and mitochondrial function. Single-molecule long-read isoform sequencing combined with RNA sequencing revealed numerous genes produce alternative splicing transcripts at high temperatures. Here, we also found that alternative oxidase, type II NAD(P)H dehydrogenases, and transcription factor Hsfs might play a crucial role in male fertility under the low-temperature condition. RNA sequencing and bulked segregant analysis coupled with whole-genome sequencing identified the candidate genes involved in the post-transcriptional modification of orf224. Overall, our study described a putative mechanism of fertility restoration in a pol TCMS line controlled by ambient temperature that might help utilise TCMS in the two-line breeding of Brassica crops.

A chromosome-level genome sequence of Chrysanthemum seticuspe, a model species for hexaploid cultivated chrysanthemum

Chrysanthemums are one of the most industrially important cut flowers worldwide. However, their segmental allopolyploidy and self-incompatibility have prevented the application of genetic analysis and modern breeding strategies. We thus developed a model strain, Gojo-0 (Chrysanthemum seticuspe), which is a diploid and self-compatible pure line. Here, we present the 3.05 Gb chromosome-level reference genome sequence, which covered 97% of the C. seticuspe genome. The genome contained more than 80% interspersed repeats, of which retrotransposons accounted for 72%. We identified recent segmental duplication and retrotransposon expansion in C. seticuspe, contributing to arelatively large genome size. Furthermore, we identified a retrotransposon family, SbdRT, which was enriched in gene-dense genome regions and had experienced a very recent transposition burst. We also demonstrated that the chromosome-level genome sequence facilitates positional cloning in C. seticuspe. The genome sequence obtained here can greatly contribute as a reference for chrysanthemum in front-line breeding including genome editing.

Productive and reproductive traits of first-calf heifers of different origin under the conditions in LLC “Green lines – Kaluga”

Dairy cattle breeding have always occupied and will continue to occupy one of the leading places in the agro-industrial complex in our country. The most eff ective method of improving existing breeds according to opinion of a number of scientists is selection in line breeding. At the same time the evaluation of breeding sires by the quality of offspring is the cornerstone of breeding work. The purpose of the research was to analyze the influence of breeding sires, as well as their linear affiliation on the economically useful characteristics of first-calf heifers under specific conditions of maintenance and use. An analysis of the milk productivity and reproductive traits of first-calf heifers of different origin by sires and different line belonging has been presented in the article. The results of intra-linear selection and crosses of genealogical lines and their influence on the productive and reproductive traits of first-calf heifers have been evaluated. The research was carried out in LLC “Green Lines-Kaluga” of the Kaluga region. It has been established that for fixing in the genotype of the offspring of plentiful milk and fat milk in purebred breeding, it is necessary to use the following sires: Aragon 2102, Tabor 1292, Lira 2047, Phlox 1448, Chudny 1167, Yalik 397, Tabun 1277, as well as intra-linear selection in the line of Montwick Chieftain 9567929 and crosses of lines in combinations: Siling Traijun Rocket 252803 – Reflection Sovereign 198998 and Wes Ideal 933122 – Siling Traijun Rocket 252803. In order to reduce the age of the first insemination of maternal stock we recommend using a combination of lines: Wes Ideal 933122 – Montwick Chieftain 9567929, Wes Ideal 933122 – Reflection Sovereign 198998, Montwick Chieftain 9567929 – Wes Ideal 933122, Montwick Chieftain 9567929 – Reflection Sovereign 198998 and Siling Trijun Rocket 252803 – Wes Ideal 933122.

A chromosome-level genome sequence of a model chrysanthemum: evolution and 1 reference for hexaploid cultivated chrysanthemum

Chrysanthemums are one of the most industrially important cut flowers worldwide. However, their segmental allopolyploidy and self-incompatibility have prevented the application of genetic analysis and modern breeding strategies. We thus developed a model strain, Gojo-0 (Chrysanthemum seticuspe), which is a diploid and self-compatible pure line. Here, we present the 3.05 Gb chromosome-level reference genome sequence, which covered 97% of the C. seticuspe genome. The genome contained more than 80% interspread repeats, of which retrotransposons accounted for 72%. We identified recent segmental duplication and retrotransposon expansion in C. seticuspe, contributing to a relatively large genome size. Furthermore, we identified aretrotransposon, SbdRT, which was enriched in gene-dense genome regions and had experienced a very recent transposition burst. We also demonstrated that the chromosome-level genome sequence facilitates positional cloning in C. seticuspe. The genome sequence obtained here can greatly contribute as a reference for chrysanthemum in front-line breeding including genome editing.

Over 50 Years of Potato Parental Line Breeding Programme at the Plant Breeding and Acclimatization Institute in Poland

The paper describes the potato parental line breeding programme developed in Poland from the 1960s. The aim of the programme was to create parental forms useful for speeding up the breeding of new potato varieties and getting higher efficiency in directed selection for desired traits. The programme introduced new sources of resistance and quality traits into the Polish breeding pool by conducting research and breeding of tetraploid and diploid parental lines. The programme had significant impact on potato breeding, with 72 Polish potato varieties originating from crossings involving parental lines. These varieties show higher levels of resistance to major pathogens of potato crops, including resistance to Potato virus Y and late blight in starch group. Besides the direct impact on potato breeding, the programme was the stimulus for developing studies focused on potato genotype.

Milk productivity and reproductive traits of cows of Holstein breed when different genealogical lines combinations

One of the modern tasks of the agricultural complex in the light of the provisions of the country’s Food Security Doctrine is to accelerate the selection progress to breed animals of the desired type. A comparative evaluation of the milk productivity and reproductive traits of cows of Holstein breed with different selection methods (intra-line breeding and genealogical line crosses) during the first lactation in the breeding farm “Barybino” – “Koalko-Agro” in the Moscow region has been presented in the article. It has been found that the highest indicators of milk productivity have been obtained when the genealogical lines were crossbred. Thus, when using sires of Pabst Governer 882933 line on cows of Montwick Chieftain 95679 line the milk yield was 8419 kg with fat content of 4,20 % and protein of 3,15 %, the open days period duration was 95 days. High productivity indicators have been characterized by cows from the combination of sires of line Wes Back Ideal 10134115 and cows of line Montwick Chieftain 95679 when milk yield was 8074 kg with fat content of 4,20 and protein of 3,10 %, the duration of the open days period was 117 days. The productivity of cows from the combination of sires of line Pabst Governor 882933 and cows of line Reflection Sovering 198998 was also characterized by high milk yield 8054 kg with fat content of 4,10 and protein of 3,0 %, the duration of the open days period was 107 days. Thus, the combination of genealogical lines has influence on the indicators of milk productivity and reproductive traits of highly productive cows, which must be taken into account when conducting breeding work.

Statistical analysis in support of maintaining a healthy traditional Siamese cat population

Background For many years, breeders of companion animals have applied inbreeding or line breeding to transfer desirable genetic traits from parents to their offspring. Simultaneously, this resulted in a considerable spread of hereditary diseases and phenomena associated with inbreeding depression. Results Our cluster analysis of kinship and inbreeding coefficients suggests that the Thai or traditional Siamese cat could be considered as a subpopulation of the Siamese cat, which shares common ancestors, although they are considered as separate breeds. In addition, model-based cluster analysis could detect regional differences between Thai subpopulations. We show that by applying optimal contribution selection and simultaneously limiting the contributions by other breeds, the genetic diversity within subpopulations can be improved. Conclusion In principle, the European mainland Thai cat population can achieve a genetic diversity of about 26 founder genome equivalents, a value that could potentially sustain a genetically diverse population. However, reaching such a target will be difficult in the absence of a supervised breeding program. Suboptimal solutions can be obtained by minimisation of kinships within regional subpopulations. Exchanging animals between different regions on a small scale might be already quite useful to reduce the kinship, by achieving a potential diversity of 23 founder genome equivalents. However, contributions by other breeds should be minimised to preserve the original Siamese gene pool.

The importance of breeding along the lines cattle of dairy breeds

The aspects of reasonableness in developing the line breeding strategy at the current status stage of dairy breeds and its significance as a factor for genetic variability have been reported. The value for milk production of the first-calf heifers within the line-bred pedigree Red-and-White cattle is estimated. Particular characteristics of the progeny produced from mating in the inbred and crossbred lines are recorded. The lower trait variability of traits was found with selecting within the crossbred lines than that in the inbred lines. Thus, the variables for the milk yield, the mass fraction of fat (MFF) in milk, and the mass fraction of protein (MFP) were less by 4–13% of the mean square deviation, 11,3–20,6%, and 14,3%, respectively. Livestock breed differentiation between the breeding lines was previously executed with the artificial elements of isolation systems. At present, the breeds widely distributed in the Russian Federation are usually “improved” with the use of Holsteins. Therefore, their genealogy and breeding structures depend on the foreign gene pool. Selection strategies for the improvement of milkability traits were implemented along with selection of bull sires capable of improving the conformation. In addition, certain herd bulls were used repeatadly. The variables for genetic values for milkability traits, which changed over time, were monitored. The herd milk production within the lines over a generation increased by 624–786 kg milk (P<0,001), while the MFF deacresed by 0,18–0,25% (P<0,001). Depending on the types of breeding, the differences in the milk yields and the MFF of the first-calf heifers between the lines comprised 178–444 kg (P<0,001) and +0.01%, respectively. However, a statistically significant difference between the lines was recorded only for the MFP, which comprised 0,03% (P<0,001).

COMBINATION ABILITY OF SELECTIVE CARP GROUPS DURING TWO-LINE BREEDING

This paper presents the results of studying the productive and physiological properties of carp crosses – interline or interbreed hybrids of the first generation. The resulting crosses have a high potential for growth, metabolism, and non-specific cellular immunity. It was found that the studied cross-breeding combinations produced a heterotic effect, which was manifested in different ways depending on the climate zone, planting density, and feeding. In the “Ergeninsky” cross, obtained from crossing the local scaly and Moldavian mirror lines, the true heterosis in relative growth rate amounted to 85–89%. As compared with the parent forms, it has a higher immune defense against pathogens, judging by the large proportion of Mature segmentonuclear neutrophils. The “Mirror” cross is the result of crossing males of the Moldavian mirror line and females of the Volga frame carp that has a scattered scale cover –100%, body weight significantly exceeds the Moldavian mirror parent form. The cross has a smaller proportion of monocytes and neutrophils in the leukogram, and the content of lysosomal cationic protein in the latter is lower, which suggests that these phagocytes are consumed in the process of immune defense. As compared with the parent forms, the cross has more intensive protein metabolism, which can be proved by the high content of total protein and albumins, ALT activity. The lipid metabolism can be determined by the content of cholesterol. The activity of creatine kinase in the “Volzhsky” cross is 2–3 times lower as compared to the initial groups. The “Volga” cross is a reciprocal interbreed hybrid of the Southern zonal type of the Chuvash scaly carp and the Volga frame carp that has a high level of lipid metabolism.