Male Sterile Lines Research Articles

A protocol for Chenopodium quinoa pollen germination

BackgroundQuinoa is an increasingly popular seed crop frequently studied for its tolerance to various abiotic stresses as well as its susceptibility to heat. Estimations of quinoa pollen viability through staining methods have resulted in conflicting results. A more effective alternative to stains is to estimate pollen viability through in vitro germination. Here we report a method for in vitro quinoa pollen germination that could be used to understand the impact of various stresses on quinoa fertility and therefore seed yield or to identify male-sterile lines for breeding.ResultsA semi-automated method to count germinating pollen was developed in PlantCV, which can be widely used by the community. Pollen collected on day 4 after first anthesis at zeitgeber time 5 was optimum for pollen germination with an average germination of 68% for accession QQ74 (PI 614886). The optimal length of pollen incubation was found to be 48 h, because it maximizes germination rates while minimizing contamination. The pollen germination medium’s pH, boric acid, and sucrose concentrations were optimized. The highest germination rates were obtained with 16% sucrose, 0.03% boric acid, 0.007% calcium nitrate, and pH 5.5. This medium was tested on quinoa accessions QQ74, and cherry vanilla with 68%, and 64% germination efficiencies, respectively.ConclusionsWe provide an in vitro pollen germination method for quinoa with average germination rates of 64 and 68% on the two accessions tested. This method is a valuable tool to estimate pollen viability in quinoa, and to test how stress affects quinoa fertility. We also developed an image analysis tool to semi-automate the process of counting germinating pollen. Quinoa produces many new flowers during most of its panicle development period, leading to significant variation in pollen maturity and viability between different flowers of the same panicle. Therefore, collecting pollen at 4 days after first anthesis is very important to collect more uniformly developed pollen and to obtain high germination rates.

Growth Regulators Improve Outcrossing Rate of Diverse Rice Cytoplasmic Male Sterile Lines through Affecting Floral Traits.

Cytoplasmic male sterility (CMS) provides an irreplaceable strategy for commercial exploitation of heterosis and producing high-yielding hybrid rice. The exogenous application of plant growth regulators could improve outcrossing rates of the CMS lines by affecting floral traits and accordingly increase hybrid rice seed production. The present study aimed at exploring the impact of growth regulators such as gibberellic acid (GA3), indole-3-acetic acid (IAA), and naphthalene acetic acid (NAA) on promoting floral traits and outcrossing rates in diverse rice CMS lines and improving hybrid rice seed production. The impact of foliar applications of growth regulators comprising GA3 at 300 g/ha or GA3 at 150 g/ha + IAA at 50 g/ha + NAA at 200 g/ha versus untreated control was investigated on floral, growth, and yield traits of five diverse CMS lines. The exogenously sprayed growth regulators, in particular, the combination of GA3, IAA, and NAA (T3) boosted all studied floral, growth, and yield traits in all tested CMS lines. Moreover, the evaluated CMS lines exhibited significant differences in all measured floral traits. L2, L3, and L1 displayed the uppermost spikelet opening angle, duration of spikelet opening, total stigma length, style length, stigma brush, and stigma width. In addition, these CMS lines exhibited the highest plant growth and yield traits, particularly under T3. Consequently, exogenous application of GA3, IAA, and NAA could be exploited to improve the floral, growth, and yield traits of promising CMS lines such as L2, L3, and L1, hence increasing outcrossing rates and hybrid rice seed production.

Heterosis and combining ability in diverse A and R lines of pearl millet tested in Western Rajasthan

The present study was conducted to estimate the combining ability and heterosis in pearl millet hybrids. Forty five pearl millet hybrids were developed using three male sterile lines (A line) with fifteen restore lines (R line) through the Line x Tester mating approach and were evaluated during kharif, 2018. Analysis of variance revealed that the mean square of treatments showed significance for all the traits. For days to 50 % flowering and days to maturity, lines viz., ICMA 93333, ICMA 97111, BIB 186, BIB 193 and BIB 281 had negative gca effect so these lines can be used as parents for hybrid development under harsh environmental conditions. Based on sca effect, heterosis and per se performance, crosses ICMA 97111 x BIB 208, ICMA 93333 x BIB 186 and ICMA 88004 x BIB 283 were identified as potential crosses for commercial exploitation of heterosis in pearl millet. Keywords: Pearl millet, male sterile lines, Line x Tester, Combining ability and heterosis

Development of New Iso-Cytoplasmic Rice-Restorer Lines and New Rice Hybrids with Superior Grain Yield and Grain Quality Characteristics by Utilizing Restorers' Fertility Genes.

This research was carried out at the Experimental Farm of Sakha Agricultural Research Station, Sakha, Kafr El-Sheikh, Egypt, during the 2018–2020 rice-growing seasons to develop and evaluate four iso-cytoplasmic rice-restorer lines: NRL79, NRL80, NRL81, and NRL82, as well as Giza 178, with ten new hybrids in order to estimate genotypic coefficient, phenotypic coefficient, heritability in a broad sense, and advantage over Giza 178 as a check variety (control) of new restorer lines. This study also estimated combining ability, gene action, better-parent heterosis (BP), mid-parents heterosis (MP), and standard heterosis (SH) over Egyptian Hybrid one (IR69A × Giza 178) as a check hybrid (control) for grain yield, agronomic traits, and some grain quality characters in restorer lines and hybrids. The percentage of advantage over commercial-variety Giza 178 (check) was significant, and highly significant among the newly developed restorer fertility lines for all the studied traits. This indicates that the selection is a highly effective factor in improving these traits. New restorer fertility lines showed highly significant positive values over commercial restorer for grain yield; the values ranged from 51% for NRL80 to 100.4% for NRL82, respectively. Meanwhile, in regard to the grain shape of paddy rice, three lines of the promising lines showed highly significant negative desirable values compared with Giza 178; the values ranged from −7.7% for the NRL80 to −15.2% for NRL79, respectively. Based on the superiority of the new lines, the new lines can be used as new restorer fertility lines to breed promising new hybrids and new inbred rice lines or varieties. From the results of the testcross experiment, the four promising lines were identified as effective restorer fertility lines for two cytoplasmic male sterile (CMS) lines. Moreover, the six rice hybrids showed values for SH heterosis of grain yield/plant of more than 15% over the check hybrid variety, with high values of 1000-grain weight and desirable grain shape; these hybrids were G46A × NRL81 (125.1%), G46A × NRL80 (66.9%), IR69A × NRL79 (47.2%), G46A × NRL79 (24.6%), IR69A × NRL81 (23.4%), and IR69A × NRL82 (16.2%).

Analysis of blast resistance genes in Longliangyou and Jingliangyou hybrid rice varieties

<p id="C3">Longke 638S and Jing 4155S, developed by Yuan Longping High-Tech Agriculture Co., Ltd. in 2014, were two thermo-sensitive genic male sterile (TGMS) lines with disease resistance, high grain quality and combining ability for producing mid-season<italic> indica</italic> hybrid rice. In this study, we analyzed the blast resistance evaluation data from the regional trials of the Longliangyou and Jingliangyou hybrid rice varieties approved by the state from 2015 to 2019. Meanwhile, to provide theoretical basis for distribution and further improvement of these hybrid rice varieties, a genotyping panel containing 16 rice blast resistance (<italic>R</italic>) genes based on KASP (Kompetitive Allele-Specific PCR) technology was developed and used for molecular detection of these hybrid rice varieties. The results showed that 43.92% of Longliangyou and Jingliangyou hybrid rice varieties conferred moderate resistance to high resistance to blast disease. The mean value of integrated disease index (IDI) and highest scale of panicle blast severity (HSPBS) was 3.3 and 4.7, respectively. These hybrid rice varieties carried different number of <italic>R</italic> genes, ranging from 3 to 7. The average number of <italic>R</italic> genes in each variety was 5.1. The distribution frequency of the five genes including <italic>Pia</italic>, <italic>Pita</italic>, <italic>Pi2</italic>, <italic>Pi5</italic>, and <italic>Piz </italic>were higher by more 50%, among which, it was 100% for <italic>Pia</italic> gene. In contrast,<italic> Pi9</italic>, <italic>Pi35</italic>,<italic> Pi36</italic>, and <italic>Pb1</italic> genes were not detected in Longliangyou and Jingliangyou hybrid rice varieties. With the increase of the number of <italic>R</italic> genes in the varieties, the mean values of IDI and HSPBS were generally decreased. In conclusion, we suggested that introduction of <italic>Pi9 </italic>into Longke 638S and Jing 4155s might lead to the further improvement of blast resistance of Longliangyou and Jingliangyou hybrid rice varieties.

Agro-morphological and molecular diversity analysis of new cytoplasmic male sterile lines in Indian cauliflower for their use in hybrid breeding

Cauliflower is a typical thermo-sensitive crop, highly responsive to heterosis for yield and stress tolerance. A diverse set comprising of 24 cytoplasmic male sterile (CMS) lines, developed across different maturity groups of Indian cauliflower, using refined Ogura, Can(napus) and Tour sterile cytoplasms was studied to understand the morphometric and molecular changes. The established Ogura-based CMS line of ‘84 series’ (in the nuclear background of snowball cauliflower) was used as an immediate source for conversion of fertile early- and mid-maturity groups lines. Observations on 18 agro-morphological traits revealed significant differences among the CMS lines, however they could not distinguish different CMS systems. The CMS system significantly reduced the floral traits (19) in almost all the transformed lines irrespective of the maturity group, however, the reduction was maximum in CMS line Tour(CMS 394–41–5) having Tour sterile cytoplasm. This CMS line had a peculiar feature of ‘gripping phenomena’ for the style which drastically reduced flower size and eventually seed yield. These CMS lines showed variation with 11 mtDNA markers and 36 genomic simple sequence repeats (gSSR), and of these, BnTR1 perfectly-identified Can(napus) and Tour CMS systems. This is the first detailed report on the extent of diversity observed in 24 new CMS lines developed using three diverse sterile cytoplasms in the nuclear background of different maturity groups of Indian cauliflower. The information will be of immense significance for immediate use in hybrid breeding and/or use as an immediate source of CMS trait for tropical cauliflowers in other regions.

Rapid and Synchronous Breeding of Cytoplasmic Male Sterile and Maintainer Line Through Mitochondrial DNA Rearrangement Using Doubled Haploid Inducer in Brassica napus.

When homozygously fertile plants were induced using doubled haploid (DH) induction lines Y3380 and Y3560, the morphology of the induced F1 generation was basically consistent with the female parent, but the fertility was separated, showing characteristics similar to cytoplasmic male sterile (CMS) and maintainer lines. In this study, the morphology, fertility, ploidy, and cytoplasm genotype of the induced progeny were identified, and the results showed that the sterile progeny was polima cytoplasm sterile (pol CMS) and the fertile progeny was nap cytoplasm. The molecular marker and test-cross experimental results showed that the fertile progeny did not carry the restorer gene of pol CMS and the genetic distance between the female parent and the offspring was 0.002. This suggested that those inductions which produced sterile and fertile progeny were coordinated to CMS and maintainer lines. Through the co-linearity analysis of the mitochondrial DNA (mtDNA), it was found that the rearrangement of mtDNA by DH induction was the key factor that caused the transformation of fertility (nap) into sterility (pol). Also, when heterozygous females were induced with DH induction lines, the induction F2 generation also showed the segregation of fertile and sterile lines, and the genetic distance between sterile and fertile lines was approximately 0.075. Therefore, the induction line can induce different types of female parents, and the breeding of the sterile line and the maintainer line can be achieved through the rapid synchronization of sister crosses and self-crosses. The induction of DH inducer in B. napus can provide a new model for the innovation of germplasm resources and open up a new way for its application.

A natural allele of OsMS1 responds to temperature changes and confers thermosensitive genic male sterility

Changes in ambient temperature influence crop fertility and production. Understanding of how crops sense and respond to temperature is thus crucial for sustainable agriculture. The thermosensitive genic male-sterile (TGMS) lines are widely used for hybrid rice breeding and also provide a good system to investigate the mechanisms underlying temperature sensing and responses in crops. Here, we show that OsMS1 is a histone binding protein, and its natural allele OsMS1wenmin1 confers thermosensitive male sterility in rice. OsMS1 is primarily localized in nuclei, while OsMS1wenmin1 is localized in nuclei and cytoplasm. Temperature regulates the abundances of OsMS1 and OsMS1wenmin1 proteins. The high temperature causes more reduction of OsMS1wenmin1 than OsMS1 in nuclei. OsMS1 associates with the transcription factor TDR to regulate expression of downstream genes in a temperature-dependent manner. Thus, our findings uncover a thermosensitive mechanism that could be useful for hybrid crop breeding.

Evaluation of Combining Ability and Heterosis of Popular Restorer and Male Sterile Lines for the Development of Superior Rice Hybrids

Twenty-four hybrids, obtained from a mating design following 6 line × 4 testers, were evaluated to estimate the heterosis, specific, and general combining ability (SCA and GCA) of parents and hybrids to find out suitable general combiner (GC) parents and cross combinations for utilization in the future breeding program. A randomized complete block design with three replications was followed to set the experiment. Data were recorded on grain yield and 13 yield-related agronomic traits. The analysis of variance of all cross combinations had highly significant differences for most of the characters studied, which indicated a wide variation across the genotypes, parents, lines, testers, and crosses. SCA and GCA variances were significant for all studied traits except for the panicle length, indicating that both non-additive and additive gene actions were involved in these traits. The GCA variance/SCA variance for all the traits was &lt;1, signifying the multitude of dominant and epistatic gene actions. The GCA effects of three lines GAN46A, IR58025A, IR62629A, and a tester IR46R were significant for the majority of the agronomic traits including grain yield and might be used for improving the yield of grains in rice as parents of excellent GC. Based on the yield of grains and agronomic traits, the hybrids IR58025A × IR46R and GAN46A × IR46R might be considered the best hybrids and another nine hybrids could also be considered good hybrids. Similarly, based on the yield of grains and agronomic traits, the positive and significant mid-parent, better parent, and standard heterosis were obtained from 3 F1s, 1 F1, and 3 F1s, respectively. Heterosis and combining ability study revealed that hybrids IR58025A × IR46R and GAN46A × IR46R might be considered preferable hybrid cultivars.

Transcriptome profiling of flower buds of male-sterile lines provides new insights into male sterility mechanism in alfalfa

BackgroundThe use of heterosis to produce hybrid seeds is a challenge to breeding for improved crop yield. In previous studies, we isolated a male sterile alfalfa hybrid and successfully obtained a genetically stable alfalfa male sterile line through backcrossing, henceforth named MS-4. In this study, we used RNA-seq technology to analyze the transcriptome profiles of the male sterile line (MS-4) and the male fertile line (MF) of alfalfa to elucidate the mechanism of male sterility.ResultsWe screened a total of 11,812 differentially expressed genes (DEGs) from both MS-4 and MF lines at three different stages of anther development. Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses revealed that these DEGs are mainly involved in processes such as energy metabolism, lipid and amino acid metabolism, carbohydrate metabolism, in addition to cell synthesis and aging. The results from protein–protein interaction (PPI) network analysis showed that the ribosomal protein (MS.Gene25178) was the core gene in the network. We also found that transcriptional regulation was an influential factor in the development of anthers.ConclusionsOur findings provide new insights into understanding of the fertility changes in the male sterile (MS-4) of alfalfa.

MALE STERILITY 3 encodes a plant homeodomain-finger protein for male fertility in soybean.

Male‐sterile plants are used in hybrid breeding to improve yield in soybean (Glycine max (L.) Merr.). Developing the capability to alter fertility under different environmental conditions could broaden germplasm resources and simplify hybrid production. However, molecular mechanisms potentially underlying such a system in soybean were unclear. Here, using positional cloning, we identified a gene, MALE STERILITY 3 (MS3), which encodes a nuclear‐localized protein containing a plant homeodomain (PHD)‐finger domain. A spontaneous mutation in ms3 causing premature termination of MS3 translation and partial loss of the PHD‐finger. Transgenetic analysis indicated that MS3 knockout resulted in nonfunctional pollen and no self‐pollinated pods, and RNA‐seq analysis revealed that MS3 affects the expression of genes associated with carbohydrate metabolism. Strikingly, the fertility of mutant ms3 can restore under long‐d conditions. The mutant could thus be used to create a new, more stable photoperiod‐sensitive genic male sterility line for two‐line hybrid seed production, with significant impact on hybrid breeding and production.

Characterization of PISTILLATA-like Genes and Their Promoters from the Distyly Fagopyrum esculentum.

Arabidopsis PISTILLATA (PI) encodes B-class MADS-box transcription factor (TF), and works together with APETALA3 (AP3) to specify petal and stamen identity. However, a small-scale gene duplication event of PI ortholog was observed in common buckwheat and resulted in FaesPI_1 and FaesPI_2. FaesPI_1 and FaesPI_2 were expressed only in the stamen of dimorphic flower (thrum and pin) of Fagopyrum esculentum. Moreover, intense beta-glucuronidase (GUS) staining was found in the entire stamen (filament and anther) in pFaesPI_1::GUS transgenic Arabidopsis, while GUS was expressed only in the filament of pFaesPI_2::GUS transgenic Arabidopsis. In addition, phenotype complementation analysis suggested that pFaesPI_1::FaesPI_1/pFaesPI_2::FaesPI_2 transgenic pi-1 Arabidopsis showed similar a flower structure with stamen-like organs or filament-like organs in the third whorl. This suggested that FaesPI_2 only specified filament development, but FaesPI_1 specified stamen development. Meanwhile, FaesPI_1 and FaesPI_2 were shown to function redundantly in regulating filament development, and both genes work together to require a proper stamen identity. The data also provide a clue to understanding the roles of PI-like genes involved in floral organ development during the early evolution of core eudicots and also suggested that FaesPI_1 and FaesPI_2 hold the potential application in bioengineering to develop a common buckwheat male sterile line.

The genetic editing of GS3 via CRISPR/Cas9 accelerates the breeding of three-line hybrid rice with superior yield and grain quality

Grain size is one of the major traits that determine rice grain yield and quality. The GS3 gene is the first major quantitative trait locus (QTL) that was identified in regulating rice grain length and weight. It was reported that the gs3 allele with a mutation in the organ size regulation (OSR) domain of the GS3 protein produced longer grains. In this study, we used the CRISPR/Cas9 gene editing technology to introduce an edited gs3 allele into our indica maintainer line, Mei1B, to enhance its grain yield and quality. Through molecular analysis and sequencing, a homologous edited-gs3 mutant line without any transgene was obtained in the T1 generation and was named Mei2B. A superior male sterile line Mei2A was generated by backcrossing the cytoplasmic male sterile (CMS) line Mei1A with Mei2B. Mei2B had a higher grain quality and yield compared to its wild-type Mei1B. Its grain length increased by 7.9%, its length/width ratio increased from 3.89 to 4.19, TGW increased by 6.7%, and grain yield per plant increased by 14.9%. In addition, genetic improvement of other quality traits including brown rice length (6.83 mm), brown rice grain length/width ratio (3.61), matched the appearance standards set for traditional Simiao (silk seedling) type cultivars. Two restorer lines were outcrossed to both Mei1A and Mei2A to produce hybrid rice. Compared to two hybrids of Mei1A, the hybrids of Mei2A had longer grains, higher length/width ratio, TGW, and yield per plant. In addition, the hybrids of Mei2A showed a better grain appearance including better translucency, a lower chalky rice rate, and degree of chalkiness than the hybrids of Mei1A. These results demonstrated that the introduction of an elite gs3 allele into Mei1A via CRISPR/Cas9 gene editing technology led to significant genetic improvement of the rice grain. The resultant CMS line Mei2A(gs3) displayed much higher grain quality and yield than the original Mei1A. Therefore, our study demonstrated that the targeted genetic improvement via gene editing technology can enhance rice breeding, especially the breeding of three-line hybrid rice.

Competitive ability of sunflower (Helianthus annuus L.) breeding material under Cyperus rotundus infestation

Abstract Weed infestation induces intense competition with the sunflower crop for soil nutrients, space and light causing significant yield losses of the sunflower. Therefore, study was undertaken during the year 2013–15 at College of Agriculture, University of Sargodha, Pakistan to determine the effect of Cyperus rotundus infestation on various morphological and biochemical traits. Initially a screening experiment was carried out to screen against C. rotundus infestation. Later on, cross combinations of selected cytoplasmic male sterile and restorer lines were attempted to develop F1 progenies which were compared with commercial hybrids along with parents. There were 6 parental lines (3 A and 3 R lines) along with 9 single cross combinations obtained from these parents. Experiment was carried out in complete randomized design having factorial arrangement with three replications. Weed in one of regime latter called as control were completely absent, while in weed infestation regimes 5 and 10 plants of C. rotundus were maintained. Results showed that C. rotundus infestation causes significant damage to the sunflower plants. Generally cross combination showed a decrease of leaf area by 440% and 264%, 61% and 49% for chlorophyll contents, 133% and 191% for head weight under low and high weed infestation regime respectively. However, antioxidant activity increased by 44% and 49% under low and high infestation regime induced by C. rotundus. Sunflower genotypes also showed variability in competitive ability against C. rotundus weed. Cross combinations coded as (A10, A7 and A2) showed lower comparative decrease for seed yield and oil contents when compared with standard hybrids under the presence of C. rotundus. Development of sunflower hybrids with better competitive ability under the presence of weeds such as C. rotundus may able to enhance plant development and lower yield losses in sunflower field with minimum the use of herbicide.

Characteristics of panicle stem growth and flowering period of the parents of hybrid rice in machine-transplanted seed production

<p id="C3">To study the characteristics of panicle and stem growth and flowering period of restorer line and sterile line under mechanized transplanting mode, and to analyze the reasons for the difficulty of parental flowering period meeting under mechanized transplanting mode Chenghui 727×Shu 21A and Yahui 2115×Yixiang 1A were selected as the materials, and the field experiment was carried out from 2019 to 2020 in this study. Two transplanting methods and seedling ages were determined. Leaf age dynamics, panicle stem growth dynamics, and heading dynamics of restorer line and sterile line were investigated, and the effects of different treatments on the growth and development of panicle, stem and leaf, and flower state of the restorer line and sterile line were statistically analyzed. The results were as follows: (1) The total number of leaves in mechanical transplanting parents decreased by 0.3-0.8 leaves in restorer lines while the sterile line added 0.1-0.4 leaves. Meanwhile, the total number of leaves in restorer lines decreased with the decrease of seedling age, while there was no significant change in the total number of leaves of male sterile lines. (2) The growth process of panicles, stems and leaves of restorer lines in mechanical transplanting was delayed by 2-5 days, while that of sterile lines was delayed by 5-10 days. The panicle differentiation of restorer lines began after jointing, while the panicle differentiation of sterile lines began 5-10 days after jointing. The panicle differentiation duration of restorer lines and sterile lines did not change significantly. The young ear growth curves of all treated parents were well fitted with Logistic curves (<italic>R</italic>²&gt;0.99). (3) The duration from seeding to heading of machine transplanting parents was longer than that of artificial transplanting parents. The effect of lengthening seedling age was the same as the change of transplanting method and the response of sterile lines to transplanting method and seedling age was more significant than that of restorer lines. (4) The flower encounter index of long seedling age under artificial transplanting in each combination was 100%, and the flower encounter was the best. Flowering encountering index was between 40%-60% of long seedling age under mechanical transplanting and short seedling age under artificial transplanting, followed by flowering status. However, the flowering index of the short seedling age combination of Chenghui 727 × Shu 21A and Yahui 2115 × Yixiang 1A was 0 and 18.18% under mechanical transplanting, respectively, indicating that the absent of flowering date seriously. In conclusion, the growth and development of ear, stem, and leaf of parents were delayed under mechanized transplanting mode, and the prolonged seedling age aggravated the growth and development lag phenomenon of parents. There were some differences in the growth, development, and flowering characteristics between restorer lines and sterile lines under different transplanting methods and seedling ages. The difference in the response of restorer lines and sterile lines to cultivation measures was the main reason for the absence of flowering dates of parents.

Assessment of sugar beet genetic diversity in the Republic of Kazakhstan by using RAPDmarkers and agromorphological traits

Sugar beet is a highly valuable and profitable crop in the Republic of Kazakhstan. It is the only source of raw materials for the production of crystalline sugar and incidentals (tops, bagasse, and molasses). This study aimed to determine the genetic diversity of 53 sugar beet samples, 19 parental lines, and 34 hybrids from Kazakhstan by using random amplified polymorphic DNA (RAPD) markers, agromorphological traits, root mass weight, and sugar content at the Kazakh Research Institute of Agriculture and Plant Growing, Almalybak, Republic of Kazakhstan. The experimental conditions were optimized for the 14 RAPD primers used in this study. The polymorphism index contents varied from 0.24 to 0.46, and all 14 primers were classified as moderately informative. The cluster analysis of RAPD data divided the sugar beet samples into seven groups. The greatest distance (D = 1.4) was noted among the male sterile lines „MS-1611‟, „MS-1631‟, „MS-97‟, and „MS-2113‟ and the pollinator lines „VP-44‟ and „VP-23‟. The samples were divided into six groups on the basis of root mass weight and sugar content via cluster analysis. The hybrids „RMS-90‟, „RMS-134‟, „RMS-133‟, „RMS-136‟, and „Ramnes‟ were grouped in a cluster that showed the highest values of root mass weight, which ranged from 610 g to 680 g. However, the samples with high sugar content (18.2–18.5), i.e., „Shecker‟, „2198‟, „H-22‟, and „1005‟, were grouped into a cluster with a distance of D = 0.8. Lines located at a large genetic distance from each other were recommended for hybridization when creating highly productive hybrids. These findings can be applied in the development of new productive and stable sugar beet hybrids in Kazakhstan.

The Unstable Restorer-of-fertility locus in pepper (Capsicum annuum. L) is delimited to a genomic region containing PPR genes.

Unstable Restorer-of-fertility (Rfu), conferring unstable fertility restoration in the pepper CGMS system, was delimited to a genomic region near Rf and is syntenic to the PPR-like gene-rich region in tomato. The use of cytoplasmic-genic male sterility (CGMS) systems greatly increases the efficiency of hybrid seed production. Although marker development and candidate gene isolation have been performed for the Restorer-of-fertility (Rf) gene in pepper (Capsicum annuum L.), the broad use of CGMS systems has been hampered by the instability of fertility restoration among pepper accessions, especially sweet peppers, due to the widespread presence of the Unstable Restorer-of-fertility (Rfu) locus. Therefore, to investigate the genetic factors controlling unstable fertility restoration in sweet peppers, we developed a segregation population (BC4F5) from crosses using a male-sterile line and an Rfu-containing line. Segregation did not significantly deviate from a 3:1 ratio for unstable fertility restoration to sterility, indicating single dominant locus control for unstable fertility restoration in this population. Genetic mapping delimited the Rfu locus to a 398 kb genomic region on chromosome 6, which is close to but different from the previously identified Rf-containing region. The Rfu-containing region harbors a pentatricopeptide repeat (PPR) gene, along with 10 other candidate genes. In addition, this region is syntenic to the genomic region containing the largest number of Rf-like PPR genes in tomato. Therefore, the dynamic evolution of PPR genes might be responsible for both the restoration and instability of fertility in pepper. During genetic mapping, we developed various molecular markers, including one that co-segregated with Rfu. These markers showed higher accuracy for genotyping than previously developed markers, pointing to their possible use in marker-assisted breeding of sweet peppers.

Identification of an anther-specific promoter from a male sterile AB line in Chinese cabbage (Brassica rapa L. ssp. pekinensis).

The online version contains supplementary material available at 10.1007/s13205-022-03160-z.

Comparative Analysis of Mitochondrial Genomes between the B-Type Cytoplasmic Male Sterility Line and Its Maintainer Line in Wheat

Cytoplasmic male sterility (CMS) is a complex phenomenon in plants, rendering them unable to produce functional pollen. In general, this is caused by an abnormal or dysfunctional mitochondrial genome. In wheat, however, the systematic structural characteristics of the mitochondrial genome from the CMS line, vis-à-vis its maintainer line, are rarely reported. Here, we identified the morphological characteristics, sequenced, assembled, and characterized the complete mitogenomes of the wheat B-type CMS line (B) and its maintainer line (YS9). The morphological results indicated that the B likely undergoes binucleate microspore abortion. The B and YS9 genomes were assembled into a typical circular molecule 452,794 and 452,453 bp in length, respectively, comprising 34 protein-coding genes (PCGs), 3 ribosomal RNA genes (rRNAs), and 16 transfer RNA genes (tRNAs). The codon usage analysis revealed leucine (Leu) and serine (Ser) as the most frequently used amino acid residues in the B and YS9 mitochondrial proteins. In particular, we uncovered a specific ORF2718, whose length of 501 bp was more 30 bp than that of the atp8 gene in the B genome, which perhaps could affect normal function of ATP8. Further, the existence of SNPs at the atp6 gene is probably associated with the CMS mechanism. This study suggests that sequencing and comparing the genomic features of the B and YS9 mitogenomes provides not only an important opportunity to conduct further genomic breeding studies, but also valuable information for future evolutionary and molecular studies of CMS in wheat.

Identification and expression analysis of phospholipase C family genes between different male fertility accessions in pepper.

Phospholipase C (PLC) is one of the major lipid-hydrolyzing enzymes, involved in lipid-mediating signal pathway. PLCs have been found to play a significant role in the growth and development of plants. In this study, the genome-wide identification and characteristic analysis of CaPLC family genes in pepper were conducted and the expression of two CaPLC genes were investigated. The results showed that a total of 11 CaPLC family genes were systematically identified, which were distributed on five chromosomes and divided into two groups based on their evolutionary relevance. Some cis-elements responding to different hormones and stresses were screened in the promoters of CaPLC genes. Quantitative real-time PCR indicated that the expression of CaPIPLC1 and CaPIPLC5 in flowers were dozens of times higher than in other tissues. In addition, with the development of flower buds, the relative expressions of CaPIPLC1 and CaPIPLC5 gradually increased in fertile materials R1 and F1. However, no expression of CaPIPLC1 and CaPIPLC5 were detected at all developmental stages of cytoplasmic male sterile lines (CMS) compared with fertile accessions. The study revealed the number and characteristics of the CaPLC family genes, which supplied a basic and systematic understanding of CaPLC family. In addition, these findings provided new insights into the role of CaPLC genes in pollen development and fertility restoration in pepper.