A total of 65 F1 vetiver hybrids were developed using the L × T design by mating 13 males with 5 females. The goal of this endeavor is to increase the possibility of developing high-yielding, quality ...essential oil varieties by utilizing heterosis and genetic variability. The heritability (%) was high for the traits CH4, CH7 to CH11 (81.90–99.69%). A positive and highly significant association exists between the features of CH2 and CH3. The trait CH8 showed the highest direct contributions to CH4, followed by CH-3, CH-5, CH4, and CH1. Heritability, correlations, and heterosis components all have an impact on the nature and degree of heterosis. It recommends that when selecting superior hybrids, breeders should take into account the genetic correlation between key traits. Based on average performance and heterosis for the root yield/plot, the top two crosses were determined to be L13 × T1 and L10 × T3. While hybrids L10 × T5, L2 × T3, and L4 × T5 showed high essential oil yield, four hybrids, L1 × T2, L3 × T3, L9 × T4, and L2 × T5, had the highest essential oil (%). A nor-sesquiterpene aldehyde (khusilal), two cedrene family chemicals (α-cedrenal and α-cedrenol), and one sesquiterpene alcohol, or khusol constitute the oil composition. The inclusion of just alcoholic and aldehydic components makes the oil fingerprint distinct. Further research was conducted on these hybrids to take advantage of heterosis and employ them in further hybridization programs to create superior genotypes.
Display omitted
Background: Selection of genotypically superior parents is most challenging task for the development of potential hybrids. In conventional plant breeding, magnitude of heterosis and inbreeding ...depression has been proved very effective in identifying vigorous parental combinations. Methods: The present investigation was carried out to study the heterosis, residual heterosis and inbreeding depression of forty sorghum crosses (F1s and F2s) obtained by crossing of eight restorer lines with five cytoplasmic male sterile lines in Line x Tester mating design in 2013 and 2014. Observations were recorded on morphological traits viz. days to 50% flowering, days to maturity, plant height, flag leaf length, flag leaf width, panicle length, panicle width, panicle weight,1000 seed weight and grain yield per plant. Result: Among all crosses, ICSA467 x UPC2 and MR750A2 x UPC2 were found to be best for most of the characters. Inbreeding depression was recorded as significantly positive for plant height for most of the crosses indicates the occurrence of transgressive segregants in F2 generation.
Understanding the quantitative genetics of crops has been and will continue to be central to maintaining and improving global food security. We outline four stages that plant breeding either has ...already achieved or will probably soon achieve. Top-of-the-line breeding programs are currently in Breeding 3.0, where inexpensive, genome-wide data coupled with powerful algorithms allow us to start breeding on predicted instead of measured phenotypes. We focus on three major questions that must be answered to move from current Breeding 3.0 practices to Breeding 4.0: ( a) How do we adapt crops to better fit agricultural environments? ( b) What is the nature of the diversity upon which breeding can act? ( c) How do we deal with deleterious variants? Answering these questions and then translating them to actual gains for farmers will be a significant part of achieving global food security in the twenty-first century.
Con el objetivo de identificar caracteres de interés agronómico, se evaluaron mediante una caracterización morfológica seis poblaciones de tomate silvestre (Solanum lycopersicum var. cerasiforme) ...para promover aquellas que expresan expectativas promisorias para futuros programas de mejoramiento genético de tomate. Las poblaciones se establecieron bajo un diseño experimental de bloques completos al azar con cuatro repeticiones. Se recogió la información de 19 caracteres relacionados a la planta, fruto, fenología y rendimiento. Se obtuvieron análisis de varianza y comparación de medias de Tukey. Se detectaron diferencias entre las poblaciones evaluadas, estas diferencias fueron importantes en los caracteres relacionados a la precocidad, número de flores, longitud entre racimos florales, número de racimos, longitud entre nudos foliares, peso promedio de fruto y sólidos solubles. Programas de mejoramiento genético en tomate para la búsqueda de resistencia a Phytophthora infestans han integrado el uso de poblaciones silvestres como una fuente de genes para introducir resistencia a los híbridos comerciales, por lo que deviene la importancia de seleccionar poblaciones resistentes con capacidad de transmitir resistencia. Con el objetivo de estimar aptitud combinatoria y heterosis para tolerancia a P. infestans, se implementó el uso de 4 poblaciones de tomate silvestre mexicano (Solanum lycopersicum var. cerasiforme) y una accesión de un pariente silvestre de tomate (Solanum pimpinellifolium), adicional al uso de 3 híbridos comerciales, como progenitores para la formación de 28 híbridos poblacionales, mediante el uso de un programa de cruzamiento a través del diseño dialélico bajo el Método II de Griffing. Los híbridos y sus progenitores fueron sometidos a infecciones naturales bajo condiciones de campo y evaluados bajo un diseño de bloques completos al azar con tres repeticiones. Se midió el área bajo la curva del progreso de la enfermedad (AUDPC) semanalmente. La información recabada permitió estimar la aptitud combinatoria general (ACG) de los progenitores, y la aptitud combinatoria específica (ACE) así mismo las heterosis de los híbridos.
Actualmente la hibridación es la técnica de mejoramiento más utilizada en Paspalum notatum Flüggé para obtener híbridos apomícticos superiores. Sin embargo, su eficiencia es muy baja. Se evaluó la ...ocurrencia de heterosis en progenies híbridas de P. notatum tetraploide, en relación con las distancias genéticas entre progenitores, y la eficiencia del uso de selección recurrente basada en aptitud combinatoria (SRAC) y selección fenotípica recurrente (SFR), partiendo de una población tetraploide sintética sexual (PTSS). Se definieron grupos de cruzamientos entre progenitores con distancia genética baja, intermedia y alta mediante marcadores moleculares. Sus progenies fueron evaluadas para variables morfo-agronómicas. Se observó una relación significativa entre distancia genética y heterosis para tres de diez variables, por lo que los marcadores moleculares podrían ser utilizados para predecir la ocurrencia de heterosis. Se generaron dos poblaciones a partir de la PTSS, una mediante SFR y la otra a partir de SRAC. Individuos sexuales de ambas poblaciones fueron cruzados con genotipos apomícticos superiores. Ambas técnicas permitieron obtener progenies híbridas que fueron evaluadas por crecimiento estival y otoñal. La progenie SFR mostró mayor crecimiento estival y heterosis que la progenie SRAC. Para crecimiento otoñal fueron similares. La SFR fue igual o más eficiente que SRAC, ya que permitió obtener mayor o igual nivel de heterosis. Las técnicas empleadas permitieron explotar la heterosis en P. notatum principalmente por la acumulación de alelos favorables dominantes.
The extent of wheat heterosis was determined by synthesizing 45 hybrids in a 10×10 diallel method, eliminating reciprocals, to determine how widespread it is. The 57 entries that made up the ...experimental material—10 parents, 45 crosses and 2 checks (HD 3086 and UP 2628), were assessed over the course of rabi 2018–19 using a Randomized Block Design (RBD) with three replications, and observations were made for 12 characters. For yield and its component traits, analyses of heterosis over mid parent, better parent and two standard checks were conducted. ANOVA exposed that there was a high significance existed among all the genotypes for all the characters studied. Yield and its contributing traits have been evaluated for their maximum heterotic range. One cross i.e., CAL/NH//H567.71/3/SER1/4/CAL/NH//H567.71/5/2* KAU2/6/...×PBW 692 showed positive significance for relative heterosis, heterobeltiosis and standard heterosis over both checks for grain yield per plant. In terms of the number of productive tillers per plant and the number of grains per spike, UP 2901×QLD 73 was found to be a superior heterotic F1. By displaying a negative significant standard heterosis over both checks, the cross between CAL/NH//H567.71/3/SER1/4/CAL/NH//H567.71/5/2*KAU2/6/...×UP 2901 demonstrated its earliness. The desired significant relative heterosis, heterobeltiosis and standard heterosis for spike length were present in HD 3234×UP 2762. The finest heterotic cross combinations for harvest index were determined to be CAL/NH//H567.71/3/SER1/4/CAL /NH//H567.71/5/2* KAU2/6/...×UP 2762 and VORB/SOKOLL×QLD 73. Higher heterotic crossings may be used to identify transgressive segregants that will increase bread wheat production and yield-contributing characteristics.
Evolving Inversions Faria, Rui; Johannesson, Kerstin; Butlin, Roger K. ...
Trends in ecology & evolution (Amsterdam),
03/2019, Letnik:
34, Številka:
3
Journal Article
Recenzirano
Odprti dostop
Empirical data suggest that inversions in many species contain genes important for intraspecific divergence and speciation, yet mechanisms of evolution remain unclear. While genes inside an inversion ...are tightly linked, inversions are not static but evolve separately from the rest of the genome by new mutations, recombination within arrangements, and gene flux between arrangements. Inversion polymorphisms are maintained by different processes, for example, divergent or balancing selection, or a mix of multiple processes. Moreover, the relative roles of selection, drift, mutation, and recombination will change over the lifetime of an inversion and within its area of distribution. We believe inversions are central to the evolution of many species, but we need many more data and new models to understand the complex mechanisms involved.
Empirical data suggest that many inversions are maintained polymorphic within populations by balancing selection, which impedes divergence and speciation.
Contrary to earlier beliefs, we here argue that balancing and divergent selection may act together shaping the frequencies of inversions, maintaining many of them polymorphic, and having important consequences for adaptation and speciation.
Inversions are not static but the derived and ancestral arrangements of an inversion continue to evolve, partly separately from each other and from the collinear genome, until lost or fixed. However, the evolution of inversions after their establishment is often neglected.
New modelling approaches and data from additional taxa are needed to understand how inversions evolve over time and space, and what roles they play in adaptation, divergence, and speciation.
•The heredity of four intrinsic qualities, i.e., total flavone, chlorogenic acid, luteoloside, and isochlorogenic acid A, is first investigated in a segregating F1 population.•Transgressive ...individuals in both directions are observed for all quality traits, and a moderate-high heritability is at 0.57 ∼ 0.84.•Three improved hybrids of superior quality are identified for breeding use.•The findings are conducive to the breeding success of high-quality tea chrysanthemums.
The active compounds in the dry head-like capitulum of tea chrysanthemums are essential contributors to human health. Therefore, increasing the internal quality is a critical aim of tea chrysanthemum breeding programs, and knowledge of the inheritance of the quality traits and accurate identification of elite hybrids is vital for breeding success. The heredity of four intrinsic qualities, i.e., total flavone, chlorogenic acid, luteoloside, and isochlorogenic acid A, were investigated in a segregating F1 population. We implemented the principal components analysis (PCA), the membership function method, and hierarchical cluster analysis (HCA) to identify hybrids of superior quality. The quality traits were widely segregated, with the coefficient of variation ranging from 0.29 to 0.88. Transgressive individuals in both directions were observed for all investigated traits. Genotypes, environments, and genotype × environment interaction significantly affected the investigated compounds, and a moderate-high heritability was at 0.57 ∼ 0.84. Total flavone, luteoloside, and isochlorogenic acid A showed highly positive heterosis (P < 0.01), while chlorogenic acid demonstrated negative heterosis, and the heterosis ratio was separately estimated at 17.11%, 127.14%, 14.51%, and -9.10%. Moreover, three elite hybrids with a comprehensive evaluation value (D) larger than 0.8 were selected for breeding use. The current study's findings add a new understanding of the inheritance pattern of the investigated active compounds, and the production of improved hybrids represents an essential step towards developing high-quality tea chrysanthemums.
PDF
