Hybrid Breeding Programs Research Articles

Protoplast isolation and culture from Kalancho\xeb species: optimization of plant growth regulator concentration for efficient callus production

A high yield of isolated protoplasts and efficient regeneration protocols are prerequisites for successful development of somatic hybrids. In the present study, protoplast isolation and regeneration were evaluated in 12 Kalanchoë accessions belonging to nine species. The highest protoplast yield was obtained from K. blossfeldiana ‘Charming Red Meadow’ with 10.78 ± 0.51 × 105 protoplasts per gram fresh weight. We observed significant differences of protoplast yield while there was no distinct difference in viability among the accessions. Seven accessions reached the microcolony stage and four developed microcalli in medium supplemented with 1.0 mg/l 1-naphthaleneacetic acid (NAA), 0.5 mg/l 6-benzylaminopurine (BAP) and 0.5 mg/l 2,4-dichlorophenoxy acetic acid (2,4-D). Using five selected accessions we optimized the PGR (plant growth regulators) concentrations using combinations of NAA, BAP and 2,4-D. K. blossfeldiana cultivars ‘Charming Red Meadow’ and ‘Paris’ produced significantly different numbers of calli depending on the PGR concentrations. For plant regeneration, the medium was supplemented with 1 mg/l NAA and 2 mg/l BAP or 2 mg/l zeatin. Shoots were regenerated on medium supplemented with NAA and BAP for K. blossfeldiana ‘Charming Red Meadow’ and K. blossfeldiana ‘Paris’. The plants successfully developed roots on the medium supplemented with IAA. The medium containing zeatin induced root formation directly from callus in K. blossfeldiana ‘Charming Red Meadow’. Our findings have the potential to facilitate the use of Kalanchoë species in somatic hybridization breeding programs.

Estimation of seed yield in oilseed rape to identify the potential of semi-resynthesized parents for the development of new hybrid cultivars.

Resynthesized (RS) Brassica napus can be used to increase the genetic diversity of this important crop plant and to develop the heterotic gene pool required for successful hybrid breeding programmes. The level of heterosis in F1 hybrids depends on the individual performance of the parents and on the degree of genetic difference between them. However, RS forms obtained from crosses of B. rapa ssp. with B. oleracea ssp. possess many undesirable agronomic traits, such as low quality of seeds, low yield and seed oil content, high erucic acid level in the oil and high glucosinolate content in seed meal. Therefore, RS oilseed rape needs to be improved by crossing with natural double-low oilseed rape, leading to selected double-low quality semi-RS lines that can be used for breeding. In this study, we evaluated the seed yield potential of F1 hybrids derived from crosses between Ogura cytoplasmic male-sterility (CMS) lines and doubled haploid (DH) semi-RS lines with restorer gene in three locations in Poland. The genotype by environment interaction (GE interaction) and general combining ability (GCA) of the restorer and CMS line effects, as well as the effects of heterosis, were also assessed. The results of the study provide the first insights into the use of semi-RS lines as components for the development of new hybrid cultivars. Even the introduction of 50% of the RS oilseed rape genotype to natural restorer lines resulted in a marked heterosis effect, with seed yield ranging from 4.56% to 90.17% more than that of the better parent. The yield of the best hybrid amounted to 108.6% of the seed yield of the open-pollinated cultivar Monolit and 94.4% of that of the hybrid cultivar Arsenal. The best DH semi-RS line S1, which had a significantly positive GCA for seed yield, can be recommended as a possible parent for inclusion in breeding programmes aimed at developing new hybrid cultivars.

Optimising protocol for successful development of haploids in marigold (Tagetes spp.) through in vitro androgenesis

For the first time, we have developed a protocol for rapid and successful induction of haploids in Tagetes spp. using in vitro androgenesis techniques. Various factors affecting the in vitro androgenesis response in Tagetes spp. were optimised. At first, a correlation was established between floret size/bud size and stage of microspore development in different genotypes of Tagetes erecta and Tagetes patula. The floret size of 3.5–4.0 mm (French marigold) and 3.0–3.5 mm (African marigold) contained the highest percent of microspores at early-uninucleate to early-binucleate stage. The frequency of shoot formation from anthers ranged from 0 to 78.6% in T. patula cv. Pusa Arpita and 0 to 63.9% in T. erecta cv. Pusa Basanti Gainda. The French marigold cultivars exhibited higher androgenic response over the African marigold cultivars. The effects of basal media, plant growth regulator combinations and sucrose concentration for direct differentiation of shoot buds and haploid induction were studied. Marigold anthers cultured on newly formulated EMS1 basal media (enriched with coconut water, AgNO3, PVP etc.) exhibited a very high androgenic response over the other commercially available media. We have also optimised the cold temperature pre-treatments and culture condition for high frequency androgenesis in marigold. Ten days cold pre-treated anthers along with 20 days dark incubation of cultures proved highly beneficial for haploid induction. Among a total of 424 anther-regenerants, 56 plants were randomly selected for flow cytometry and cytological analysis. The ploidy analysis revealed 14.3% of anther regenerants as dihaploids, 66.1% as tetraploid (similar to donor mother plant) and 19.6% as polyploid. The determination of ploidy level by counting the number of chloroplast in stomatal guard cells of marigold was also established for rapid screening of haploids. The identified haploids were successfully diploidised and are being utilised in the hybrid breeding programme at our institute. The developed protocol will facilitate doubled haploids based breeding in Tagetes spp. This is the first report of successful induction of haploids in Tagetes spp. using in vitro androgenesis techniques. We have studied various factors affecting the in vitro androgenesis response in Tagetes spp. A correlation was established between floret size/ bud size and stage of microspore development in different genotypes of Tagetes erecta and Tagetes patula. Basal media and cultural conditions were optimised for high frequency androgenesis in marigold. Haploids were successfully induced and their ploidy level was assessed through flowcytometry and cytological analysis.

Estimation of Gene Action, Heritability and Pattern of Association among Different Yield Related Traits in Upland Cotton

A random mating design comprising 6 varieties (FH-142, MS-DK, IUB-63, KZ-189, FB-3159, and VH-300) and F1 crosses was used to check gene action for yield contributing traits in upland cotton. Heritability and correlation were calculated from F3 populations of the cross CRS-456×Jumbo okra. The randomized complete block design was used in both experiments with three replication at the Department of Plant Breeding and Genetics, University of Agriculture Faisalabad, Pakistan during 2015-2017. In both experiments, analysis of variance indicated significant variation present among the accessions of the upland cotton for all the traits (plant height, sympodial and monopodial branches, nodes number of 1st sympodial branch, height of 1st sympodial branch, bolls per plant, boll weight, lint weight, seed cotton yield, seed index, lint percentage, lint index, seeds per boll, fiber fineness, fiber strength, fiber length and fiber uniformity) under study. Mean values of all genotypes were significantly different from each other for all the traits studied. All the parameters manifested positive correlation with seed cotton yield except plant height, monopodia per plant, nodes number of 1st sympodia, height of 1st sympodia, bolls per plant, seed index and lint index. The inheritance of all the traits in F1 crosses was generally controlled by overdominance gene action except monopodial branches, nodes number of 1st sympodial branch, height of 1st sympodial branches, boll weight, fiber length and fiber uniformity that were partially controlled under additive gene action. Epistasis was not found to be involved in any of the traits. Estimation of broad sense heritability (h2 b. s) in F3 populations were high (60-97%) for all the traits under study. Results suggested form heritability and correlation that these traits can be improved either through appropriate selection method or hybrid breeding programme.

Genome-wide haplotype analysis improves trait predictions in Brassica napus hybrids

Combining ability is crucial for parent selection in crop hybrid breeding. Many studies have attempted to provide reliable and quick methods to identify genome regions in parental lines correlating with improved hybrid performance. The local haplotype patterns surrounding densely spaced DNA markers include a large amount of genetic information, and analysis of the relationships between haplotypes and hybrid performance can provide insight into the underlying genome regions which might contribute to enhancing combining ability. Here, we generated 24,403 single-copy, genome-wide SNP loci and calculated the general combining ability (GCA) of 950 hybrids from a diverse panel of 475 pollinators of spring-type canola inbred lines crossed with two testers for days to flowering (DTF) and seed glucosinolate content (GSL). We performed a genome-wide analysis of the haplotypes and detected eight and seven haplotype regions that were significantly associated with the GCA values for DTF and seed GSL, respectively. Additionally, two haplotype blocks containing orthologs of flowering time genes FLOWERING LOCUS T (FT) and FLOWERING LOCUS C (FLC) on chromosome A02 showed additive epistatic interactions influencing flowering time. Moreover, two homoeologous haplotype regions on chromosomes A02 and C02 corresponded to major quantitative trait loci (QTL) for GSL which showed additive effects related to reduction of seed GSL in F1 hybrids. Our study showed that haplotype analysis has the potential to substantially improve the efficiency of hybrid breeding programs.

Combining ability analysis for yield and quality traits in ridge gourd (Luffa acutangula L. Roxb.)

The investigation was carried out to study combining ability in ridge gourd through line × tester analysis in which 11 lines were crossed with 3 testers to get 33 F1 hybrids. These 33 F1s along with 14 parents were evaluated in Randomized Block Design with three replications under four environments consisting of two locations and two seasons during 2016-17. The parents DRG-3, DRG-5, DRG-15 and Konkan Harita were good general combiners for fruit yield, fruit quality and yield attributing traits and therefore, these are proposed for their further utilization in hybrid breeding programme. Hybrids DRG-15 × Konkan Harita and DRG-3 × Konkan Harita exhibited good specific combining ability for yield per plant and yield contributing characters like number of fruits per plant, fruit weight and fruit diameter. These superior combinations can be further promoted to be utilized as hybrids.

Preliminary investigation of the effect of ethyl 4'fluorooxanilate as a male gametocide of sweet stem sorghum

ABSTRACTAn effective male sterility system enables targeted crosses between parent plants with desired and complementary characteristics. The use of chemical hybridising agents (CHAs) to induce male sterility is quicker and more efficient than manual emasculation. This study investigated the concentration, stage of application and frequency of application of ethyl 4'fluorooxanilate (E4FO) for inducing male sterility of sweet stem sorghum without affecting female fertility. In Trial 1, the dose rate of E4FO was determined to optimise male sterility. In this experiment three genotypes were tested at E4FO dose rates. In Trial 2 the frequency of application of E4FO was determined using three sweet stem sorghum genotypes, three E4FO doses, and six frequencies of application. Data on sterility was inferred based on seed set and seed count from the treated plants. Male sterility was achieved when E4FO was applied during heading stage using the following rates: 1 g l−1, 1.5 g l−1 and 2 g l−1, with more than one application. Applying E4FO twice during the heading stage at a rate of 2 g l−1 would induce male sterility in the tested sweet stem sorghum genotypes, a result that could be useful in hybrid breeding programmes.

Genome-wide Identification of Chile Pepper Pentatricopeptide Repeat Domains Provides Insight into Fertility Restoration

Pentatricopeptide repeat (PPR) proteins constitute one of the largest protein families in plants. They are typically targeted to the mitochondria or chloroplast and bind to one or more organellar transcripts, influencing expression. Genes responsible for inhibiting the mitochondrial genes that cause cytoplasmic male sterility (CMS), restorer-of-fertility (Rf) genes, often encode PPRs. Using in silico techniques, 552 PPR domains were identified throughout the chile pepper (Capsicum annuum) genome. The domains were mapped across 12 chromosomes and were found to be largely distally or proximally located. About 28% of the chile pepper PPR domains identified in this study have high structural similarity to previously reported PPRs in arabidopsis (Arabidopsis thaliana). In addition, 11 candidate Rf genes clustered on chromosome 6, and 1 on chromosome 1 were identified that were characterized in 16 A- (S rfrf), B- (N rfrf), and C-line (N RfRf) backgrounds. These findings support a multigene model for fertility restoration and broaden our understanding of the restoration of fertility. This may be an explanation for the lack of widely applicable molecular markers for this important trait. With this new information, specific Rf markers may be developed and will facilitate the implementation of hybrid breeding programs in chile pepper. In addition, this work provides a basis for future research in PPRs, an increasingly important gene family.

English

The Ethiopian garden cress (Lepidium sativum L.) is an important crop extensively used as food and medicine. In this study, total seed storage proteins of 112 garden cress genotypes collected from diverse growing regions in Ethiopia were investigated to assess patterns of genetic diversity and relationships. Using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), a total of 1774 stable protein bands were identified through discontinuous electrophoresis. Of these, 1597 bands were polymorphic. A maximum of 20 protein sub-units in the range of 15 to 75 kDa were observed per genotype. The similarity coefficient among these genotypes ranged from 0.25 to 1.00 with an average genetic dissimilarity of 0.2754. On the basis of Ward Euclidian distance, the genotypes were grouped into five major clusters, the largest one comprised of 62 genotypes (Cluster III) followed by 26 genotypes in Cluster I. Cluster IV and V contained a total of 14 genotypes that were the most distantly related to other groups, and thus can be potentially used as parents for exploitation of heterotic effects in hybrid breeding programs. Our findings using SDS-PAGE profiles revealed no obvious association between geographic region of origin and germplasm clustering. However, the polymorphism and cluster analysis indicated that garden cress genotypes differed greatly in the composition of seed proteins. This shows that protein profiling could be used as a rapid and reliable method for genetic diversity studies. In order to fully explore the protein based genetic diversity in garden cress germplasm, techniques such as 2-D gel electrophoresis are recommended in future studies.   Key words: Cluster analysis, dissimilarity index, garden cress, Lepidium sativum, protein polymorphism, protein profiling, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), seed storage protein.

Assessment of genetic diversity among sunflower genotypes using microsatellite markers.

Genetic diversity estimation of plant materials is one of the important pre-breeding activities in breeding field crops. Twenty-one microsatellite markers used to assess genetic diversity and relationship of 68 sunflower genotypes (Helianthus annuus L.). All of 21 pairs of SSR (Simple Sequence Repeats) markers produced a total number of 49 polymorphic bands. DNA fragments ranged from 92 to 850 bp. The highest and lowest polymorphic information content (PIC) values were determined as 0.58 and 0.10 for marker Ha806-ar and Ha494-ar. The number of alleles per locus was calculated as 2-6 with the average of 2.86. In this study, CMS (Cytoplasmic Male Sterility) lines showed the highest and Iranian hybrids showed the least polymorphism, respectively. Principal coordinates analysis revealed that Iranian hybrids were well-separated compare to the other groups. The analysis of molecular variance (AMOVA) indicated higher genetic variation within groups (90%) rather than among groups (10%). This study revealed that the SSR markers such as Ha806-ar could be a useful tool for distinguishing sunflowers genotypes. According to the study, there is a significant genetic distance among individuals. Parental lines (R26 and CMS502 lines with lowest similarity coefficient) may be useful for future sunflower crossing and hybrid breeding programs. Generally, high similarity coefficient estimation among investigated sunflower groups revealed that there was a narrow genetic base in investigated materials suggesting broadening its genetic base by introduction of new genes into existing breeding materials.

Embryogenic callus initiation from leaf explants of Elaeis oleifera x Elaeis guineensis (OxG) hybrids

Elaeis oleifera x Elaeis guineensis (OxG) hybrid is an oil palm interspecific crossbreed to produce a variety with better oil quality, slow stem growth, and resistance to bud rot disease. However, one of the problems in OxG hybrid breeding program is an inefficiency in the conventional propagation method, while the protocol for OxG hybrid tissue culture has not been established yet in Indonesia. Somatic embryogenesis (SE) using a temporary immersion system (TIS) will be used for OxG clonal propagation as it has been established successfully in E. guineensis. Explants were young leaves derived from genotypes of selected F1 and backcross (BC) of OxG hybrids where the E. oleifera was originated in Brazil and Suriname. Callus initiation used eight media with various compositions of minerals, hormones, and active charcoal. Initial callus emerged in 8-10 weeks after culture. The average of callogenesis frequency was 3.49% in F1 and 5.59% in BC hybrid explants, with the highest at 10.73% occurred in BC Brazil. Callogenesis of OxG hybrid showed a high potency as callogenesis of E. guineensis. The callus had nodular structure which was potentially embryogenic. After 3 cultures, some of the embryogenic calli were transferred to TIS for somatic embryo induction.

Marker-Assisted Improvement of the Elite Maintainer Line of Rice, IR 58025B for Wide Compatibility (S5n ) Gene.

The degree of heterosis in different hybrid rice varieties is reported to be at the highest in indica/japonica cross combination, however, there is a problem of sterility and semi-sterility in such inter sub specific hybrids. To overcome this problem, it is essential to develop parental lines having wide compatibility (S5n) gene. In this study, a functional marker S5-InDel was used for marker-assisted backcrossing (MABB) to introgress S5n gene from Dular into the genetic background of a widely grown recurrent parent IR 58025B, a maintainer line of wild-abortive (WA) cytoplasmic male sterile line, IR 58025A. Further, a closely linked marker nksbadh2 was used for the identification of plants devoid of aroma in backcross population to develop hybrids with no aroma. The stringent phenotypic selection followed by background selection of BC3F4 identified plants with 94.51–98.90% of the recurrent parent genome recovery of lines carrying S5n gene. Subsequently, at 10 promising BC3F5 lines possessing S5n gene with high yielding and long-slender grain type were validated for their maintainer behavior through test crosses with IR 58025A. Also the improved lines showed significantly improved spikelet fertility performance while crossed with japonica and javanica testers in comparison to the original recurrent parent. The improved lines developed in the present study, are being converted to CMS lines through marker-assisted backcross breeding to facilitate precise and improved hybrid breeding program in rice.

Phenotypic Data from Inbred Parents Can Improve Genomic Prediction in Pearl Millet Hybrids.

Pearl millet is a non-model grain and fodder crop adapted to extremely hot and dry environments globally. In India, a great deal of public and private sectors’ investment has focused on developing pearl millet single cross hybrids based on the cytoplasmic-genetic male sterility (CMS) system, while in Africa most pearl millet production relies on open pollinated varieties. Pearl millet lines were phenotyped for both the inbred parents and hybrids stage. Many breeding efforts focus on phenotypic selection of inbred parents to generate improved parental lines and hybrids. This study evaluated two genotyping techniques and four genomic selection schemes in pearl millet. Despite the fact that 6× more sequencing data were generated per sample for RAD-seq than for tGBS, tGBS yielded more than 2× as many informative SNPs (defined as those having MAF > 0.05) than RAD-seq. A genomic prediction scheme utilizing only data from hybrids generated prediction accuracies (median) ranging from 0.73-0.74 (1000-grain weight), 0.87-0.89 (days to flowering time), 0.48-0.51 (grain yield) and 0.72-0.73 (plant height). For traits with little to no heterosis, hybrid only and hybrid/inbred prediction schemes performed almost equivalently. For traits with significant mid-parent heterosis, the direct inclusion of phenotypic data from inbred lines significantly (P < 0.05) reduced prediction accuracy when all lines were analyzed together. However, when inbreds and hybrid trait values were both scored relative to the mean trait values for the respective populations, the inclusion of inbred phenotypic datasets moderately improved genomic predictions of the hybrid genomic estimated breeding values. Here we show that modern approaches to genotyping by sequencing can enable genomic selection in pearl millet. While historical pearl millet breeding records include a wealth of phenotypic data from inbred lines, we demonstrate that the naive incorporation of this data into a hybrid breeding program can reduce prediction accuracy, while controlling for the effects of heterosis per se allowed inbred genotype and trait data to improve the accuracy of genomic estimated breeding values for pearl millet hybrids.

Assessment of genetic diversity in advanced breeding lines derived from intraspecific crosses of garden pea (Pisum sativum L.)

An intraspecific hybrid breeding program involving six crosses, Palam Sumool (PS) × Palam Priya, PS × Pb-89, PS × Azad P-1, PS × Palam Triloki and VRPMR10 × Sugar Giant, Green Pearl × DPP-9411 was initiated in 2006 onwards followed by pedigree selection, resulted in isolation of 45 genotypes with desirable attributes. These progenies along with five recommended varieties were evaluated during 2014-15 to assess degree of divergence. A considerable genetic diversity was observed among genotypes, dispersed in 18 diverse clusters. Of these, 17 were monogenotypic while cluster I had maximum genotypes. Internodal length contributed maximum towards total genetic divergence followed by nodes per plant, protein content and average pod weight. Superior performing genotypes viz., ‘DPP-2011-SP-7’, ‘DPP-2011-SP-17’, and ‘DPP-2011-SP-24’ from cluster I and ‘DPP-2011-SP-6’, ‘DPP-2011-SP-22’ ‘DPPMR-09-1’, ‘DPPMR-09-2’, ‘DPP-2011-SN-5’ and ‘Palam Triloki’ from monogenotypic clusters offer promise for their direct use as varieties and as potential parents in future breeding programmes.

Genotypic response towards haploid induction in short day tropical Indian onion (Allium cepa)

Doubled haploid technology is advantageous for a cross pollinated crop with high inbreeding depression like onion that takes 12 years to develop inbreds through conventional breeding. Inbred development through haploid technology takes only 1 to 2 years and will be a boon for heterosis breeding programme. Two media (HAP02, HAP04) and seven genotypes were assessed for their response towards haploid induction. HAP04 was significantlysuperior to HAP02 for embryo induction. Significant differences in media towards callus formation and significant differences in media and genotypes towards embryo induction were observed. Open pollinated varieties and hybrids were more responsive towards embryo induction followed by exotic and landrace, whereas callus induction was more in landrace. Days for embryo induction were lower in PWF (65-83), whereas RCL was the best respondinggenotype (2.22 shoots/plant) for multiple shoot induction. About 33% plants survived and haploids, spontaneous diploids and tetraploids were obtained. Gamborg's B5 medium supplemented with 2,4-D and BA @ 2 mg/l each was the best media. This study will form a basis for inbred development to accelerate hybrid breeding programme in short day tropical Indian onion.

Exploiting the Rht portfolio for hybrid wheat breeding.

The portfolio of available Reduced height loci (Rht-B1, Rht-D1, and Rht24) can be exploited for hybrid wheat breeding to achieve the desired heights in the female and male parents, as well as in the hybrids, without adverse effects on other traits relevant for hybrid seed production. Plant height is an important trait in wheat line breeding, but is of even greater importance in hybrid wheat breeding. Here, the height of the female and male parental lines must be controlled and adjusted relative to each other to maximize hybrid seed production. In addition, the height of the resulting hybrids must be fine-tuned to meet the specific requirements of the farmers in the target regions. Moreover, this must be achieved without adversely impacting traits relevant for hybrid seed production. In this study, we explored Reduced height (Rht) loci effective in elite wheat and exploited their utilization for hybrid wheat breeding. We performed association mapping in a panel of 1705 wheat hybrids and their 225 parental lines, which besides the Rht-B1 and Rht-D1 loci revealed Rht24 as a major QTL for plant height. Furthermore, we found that the Rht-1 loci also reduce anther extrusion and thus cross-pollination ability, whereas Rht24 appeared to have no adverse effect on this trait. Our results suggest different haplotypes of the three Rht loci to be used in the female or male pool of a hybrid breeding program, but also show that in general, plant height is a quantitative trait controlled by numerous small-effect QTL. Consequently, marker-assisted selection for the major Rht loci must be complemented by phenotypic selection to achieve the desired height in the female and male parents as well as in the wheat hybrids.

A review of research advances on the biology and artificial breeding of groupers

PDF HTML阅读 XML下载 导出引用 引用提醒 石斑鱼生物学及人工繁育研究进展 DOI: 作者: 作者单位: 1. 福建省海洋生物资源开发利用协同创新中心, 福建 厦门 361102;2. 厦门大学 海洋生物多样性与全球变化研究中心, 厦门大学 海洋与地球学院, 福建 厦门 361102;3. 厦门大学 海洋生物制备技术国家地方联合工程实验室, 厦门大学 海洋与地球学院, 福建 厦门 361102 作者简介: 丁少雄(1973-),教授,从事鱼类资源保护与遗传育种研究.E-mail:sxding@xmu.edu.cn 通讯作者: 中图分类号: S917 基金项目: 科技部科技基础性工作专项（2013FY110700）；海南大学南海海洋资源利用国家重点实验室开放课题（2016001）. A review of research advances on the biology and artificial breeding of groupers Author: Affiliation: 1. Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological Resources, Xiamen 361102, China;2. Marine Biodiversity and Global Change Research Center, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China;3. State-Province Joint Engineering Laboratory of Marine Bioproducts and Technology, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:石斑鱼（Epinephelidae）是名贵的海产鱼类，主要栖息于热带亚热带近岸岩滩和珊瑚礁水域，是岩礁生态系生物群落的重要类群。本文对国内外石斑鱼类生物学、生态学、渔业资源及人工繁育养殖的研究成果进行梳理，综合报道石斑鱼类的形态比较特征，栖息、摄食和繁殖习性，系统演化与分类，种类地理分布，人工繁育等研究进展以及养殖发展概况；报道全球石斑鱼自然资源明显衰退的现状评估以及对石斑鱼资源保护的共识和相关的渔业管理措施。此外，根据作者多年开展的鱼类遗传生物学研究，指出强化我国海域野生石斑鱼资源保护工作，深入开展杂交石斑鱼的基础生物学研究，加强石斑鱼杂交选育行业管理，是我国石斑鱼渔业产业可持续发展的必要保障。 Abstract:Groupers (family Epinephelidae) are an important group of marine fishes, which inhabit coral reefs and rocky coastlines of the tropics and subtropics. They are top predators and keystone species, which are central to ecosystem stability and resilience, as well as major sources of food, economic income, recreation for fishermen, and display animals. However, many species are threatened by overfishing, habitat degradation and pollution, and hybridization with commercial stock escapees. Such threats to their longer term existence emphasize the need for well-developed management and protection plans that include best practices for their farming. To address these needs, we provided a comprehensive review of the literature on grouper biology, ecology, fishery resources, and farming. Specifically, we synthesized global research on grouper morphology, behavior, ecology, evolution, and biogeography with more applied knowledge on their artificial breeding, aquaculture, fishery management and public protection, and conservation status. In particular, we used our synthesis of grouper genetics to conclude that hybridization with commercial escapees remains a major, but largely overlooked threat to the long-term integrity of many natural groups. Thus, we suggested greater oversight on artificial hybrid breeding programs. Such focus should be a primary component of any future plans to ensure the sustainability of the Chinese fishery and farming industries for groupers. 参考文献 相似文献 引证文献

Genomic selection of crossing partners on basis of the expected mean and variance of their derived lines.

In a line or a hybrid breeding program superior lines are selected from a breeding pool as parental lines for the next breeding cycle. From a cross of two parental lines, new lines are derived by single-seed descent (SSD) or doubled haploid (DH) technology. However, not all possible crosses between the parental lines can be carried out due to limited resources. Our objectives were to present formulas to characterize a cross by the mean and variance of the genotypic values of the lines derived from the cross, and to apply the formulas to predict means and variances of flowering time traits in recombinant inbred line families of a publicly available data set in maize. We derived formulas which are based on the expected linkage disequilibrium (LD) between two loci and which can be used for arbitrary mating systems. Results were worked out for SSD and DH lines derived from a cross after an arbitrary number of intermating generations. The means and variances were highly correlated with results obtained by the simulation software PopVar. Compared with these simulations, computation time for our closed formulas was about ten times faster. The means and variances for flowering time traits observed in the recombinant inbred line families of the investigated data set showed correlations of around 0.9 for the means and of 0.46 and 0.65 for the standard deviations with the estimated values. We conclude that our results provide a framework that can be exploited to increase the efficiency of hybrid and line breeding programs by extending genomic selection approaches to the selection of crossing partners.

Morphological and Molecular Analyses of Reciprocal Hybrids between ‘Slim Whitman’ and ‘Pinza’, Two Narcissus pseudonarcissus Cultivars

Narcissus pseudonarcissus, also known as daffodil, is a world-famous ornamental flower. In this study, for the first time, cross-pollinations between two widely cultivated N. pseudonarcissus varieties ‘Slim Whitman’ and ‘Pinza’ were performed. After eight consecutive years of cultivation, 27 reciprocal hybrids with different genotypes survived; 15 hybrids in ‘Slim Whitman’ × ‘Pinza’ and 12 in ‘Pinza’ × ‘Slim Whitman’. Twenty ornamental and agronomic characters were observed to evaluate the pattern and extent of genetic variability of the hybrids and relatedness with their parents. The hybrids showed great variation in most morphological characters compared with the parents, especially in leaf and flower characters. Hybrids SP03, SP04, SP05, SP12, SP13, PS04, PS06, PS07, PS08, and PS11 had evident growth advantage in some aspects compared with both parents. Of these hybrids, SP04 got novel flowers with white petals and an yellow-orange corona, and had the potential to become a new popular N. pseudonarcissus cultivar. Hybrids SP01, SP03, SP05, PS04, PS06, and PS07 also possessed a great ornamental value. Using cluster analysis based on morphological traits and random amplified polymorphic DNA (RAPD) molecular markers, genetic relationships among the reciprocal cross hybrids and their parents were further analyzed. The 27 reciprocal hybrids and their parents grouped into divergent clusters, showing that there was rich genetic variation among the hybrids tested. This study will pave the way for hybridization breeding programs of N. pseudonarcissus.

Estimation of combining ability and gene action for yield and its components in pigeonpea [Cajanus cajan (L.) Millspaugh

Twenty eight hybrids developed by utilizing eight parents in 8 x 8 diallel mating design excluding reciprocals were evaluated in randomized block design with three replications for twelve characters in order to understand the combining ability and gene action in pigeonpea. The analysis of variance for combining ability revealed presence of additive and non- additive gene action. The ratio of gca/sca variance was less than unity which indicated the preponderance of non- additive gene action for action in the control of pod length, harvest index, protein content and leaf area. The estimates of general combining ability suggested that parents ICPL-87119, GT-103 and AGT-2 were good general combiners for seed yield per plant and its attributing characters while, hybrids UPAS-120 x GT-103, BSMR-853 x BANAS and BSMR-853 x GT-1 showed the higher order sca effect for seed yield per plant. These cross combinations can be potentially utilized in hybrid breeding programmes.