Synthetic Varieties Research Articles

Breeding synthetic varieties in annual caraway: observations on the outcrossing rate in a polycross using a high-throughput genotyping system

Caraway (Carum carvi) is an economically important spice and medicinal plant of the Apiaceae family (syn. Umbelliferrae). Farmers often favor annual cultivation of caraway. However, the annual varieties, which are currently available, do not provide satisfying seed yields. Employing heterosis can be a promising approach to increase yield. Breeding of synthetic varieties utilizes heterosis and may be the method of choice for future caraway breeding. Knowledge of the outcrossing rate is important to evaluate the effectiveness of this breeding method. However, the outcrossing rate of caraway is unknown so far. We estimated the outcrossing rate of seven inbred lines under field conditions in a neighbor-balanced polycross design. For this purpose, we implemented a high-throughput genotyping system (PACE), accompanied by a high-throughput method for DNA extraction adapted to caraway. In total, more than 1300 individual plants were genotyped. We found a high variability of lines regarding outcrossing rate and other traits associated with flowering. The outcrossing rate was on average 66.5% and ranged from 51.6 to 82%. We discussed implications of our findings on the targeted breeding method.

GENETIC VARIABILITY AND ASSOCIATION AMONG SEEDLING TRAITS OF ZEA MAYS UNDER DROUGHT STRESS CONDITIONS

Maize is an important food crop for human and feed for animals or livestock. It is highly sensitive for abiotic and biotic stress conditions. An experiment was conducted in the greenhouse of Institute of Molecular Biology and Biotechnology, The University of Lahore for the determination of effects of drought on maize growth related seedling traits. Four maize genotypes/varieties viz., B-316, Raka-poshi, Pak-Afghoi and EV-1097Q were grown to evaluate the effects of drought stress. Four drought treatments were used including 20% irrigation water, 40% irrigation water, 60% irrigation water, 80% irrigation water, 90% irrigation water and control or 100% irrigation water. It was found that the genotypes B-316 and Raka-poshi showed better performance for all studied traits especial shoot and root length as compared with other two genotypes EV-109Q and Pak-Afghoi. The minimum effects of drought were reported at control and 90% irrigation water. The effects of drought were increased with the increase in concentration of drought stress. The adverse drought effects were reported under the treatment of drought at 20% and 40% irrigation water. The higher genetic advance and heritability was recorded for root length, shoot length, dry shoot weight and dry root weight. The significant correlation was recorded between root length, shoot length and dry shoot weight. The higher contribution for shoot length was reported for root length, dry shoot weight and number of roots per plant. It was concluded from study that the selection of maize genotypes on the basis of root length, shoot length and dry shoot weight may be fruitful to produce drought stress tolerance maize hybrids and synthetic varieties.

Developing Heterotic Groups for Successful Hybrid Breeding in Perennial Ryegrass

Perennial ryegrass (Lolium perenne L.), an important forage grass species in temperate regions, is genetically improved by population breeding. Although valued for their broad genetic base, the resulting synthetic varieties only partially exploit heterosis. Hybrid breeding offers opportunities to fix beneficial heterotic patterns more effectively and, hence, to increase the yield potential. A suspected bottleneck in the production of perennial ryegrass hybrids is the genetic intermixture of existing germplasm, impeding the definition of heterotic groups. In this study, selected parental populations of a diploid and tetraploid cytoplasmic male sterility (CMS)-based hybrid breeding program were characterized using genotyping-by-sequencing (GBS). Hybrid populations, derived from 26 parental combinations of the tetraploid breeding program, were tested for yield performance and compared to synthetic varieties at five sites over four growing seasons. The hybrids significantly outperformed the synthetics by 4.15% on average for total dry matter yield. Additionally, GBS revealed the existence of sub-populations within the tetraploid CMS germplasm. This sub-population structure represents the untapped potential that could be exploited for heterosis to further increase biomass yields. Here, we show that CMS hybrids generate substantial yield gains in perennial ryegrass and provide a method to further improve hybrid breeding, using GBS to select for heterotic groups.

Оцінка комбінаційної здатності вихідного матеріалу помідора за ознакою «уміст лікопену в плодах»

Goal. To assess the combinatorial ability of the tomato source material by sign «lycopene content in the fruit» in the system of diallel crosses. Methods. Field — to establish differences between variants of the experiment; laboratory — to determine the content of lycopene in the fruit; genetic — to determine the indicators of combinatorial ability; mathematical and statistical — to assess the reliability of the research results. Results. Studies identified samples that should be used for heterosis and varietal selections, as well as those that should be used only when creating synthetic varieties. The established advantages of additive effects in the genetic control of the sign «lycopene content in tomato fruits» made it possible to select phenotype in the 2nd hybrid generation. Conclusions. Samples MO 112 and T-3627 should be used to create heterosis hybrids and as a component of synthetic varieties. The Dark green sample, Alia variety, and the № 477 lines can be used to create synthetic varieties. The established advantage of additive effects in the genetic control of the sign «lycopene content in tomato fruits» makes it possible to recommend selection in the selection process by phenotype, starting from the 2nd hybrid generation.

Fenotipeo y selección de líneas S1 segregantes de maíz tolerantes a estrés hídrico

La sequía reduce el rendimiento de grano del maíz; se requiere obtener líneas tolerantes a sequía para formar híbridos o variedades sintéticas. Los objetivos fueron: 1) fenotipear la población segregante en ambientes contrastantes de humedad, 2) seleccionar líneas de rendimiento alto y ASI corto con base a sequía y riego; y 3) determinar la heredabilidad y correlación de caracteres. El germoplasma fueron 193 líneas S1, progenitores y testigo; estos se evaluaron bajo riego y sequía inducida bajo el diseño látice alfa con dos repeticiones en dos localidades del Estado de Morelos, México. Las variables fueron floración masculina (FM) y femenina (FF), intervalo antesis-emergencia de estigmas (ASI), altura de planta (AP) y mazorca (AM); y rendimiento de grano (RG). Se observó reducción del 40 % en RG bajo sequía (0.75 t ha-1) con respecto a riego (1.26 ton ha-1), el ASI fue de 5 y 2 d en sequía y en riego, respectivamente. La heredabilidad para RG y ASI fue de 0.41. Existen líneas con herencia transgresiva para RG y ASI. La correlación del RG con FF y ASI fue de -0.23**y -0.37**, respectivamente. Existe germoplasma para generar una variedad sintética tolerante a estrés hídrico o iniciar un programa de hibridación.
 

New generation surface synthetic of alfalfa sowing (Medicago sativa L.)

Aim. Evaluation of starting material on a complex of economically valuable features and creation with its participation of a variety-synthetics of alfalfa sowing. Methods. Field, laboratory. Results. The results of research and creation of a synthetic variety of alfalfa of sowing Radoslav at the Institute of forages and agriculture of Podillya of NAAS are presented. Listed on the State Register of Plant Varieties Eligible for Distribution in Ukraine (hereinafter – the Register of Plant Varieties of Ukraine) (Certificate of State Registration No. 15196001 of March 14, 2019, Patent for the Plant Variety of Radoslaw No. 190654 of May 5, 2019). When evaluating fodder and seed productivity in the research fields of the institute, the preference for the Radoslav variety to the Sinyukh standard was established. Extensive testing of the suitability of the variety for propagation (SPD) in 5 research points of the Polesia zone and 4 ˗ of the Forest-Steppe Institute of Plant Variety Examination confirmed higher rates of fodder and seed productivity and growth rate of the specified variety compared to the conventional standard. Conclusions. In order to enhance the efficiency of the breeding process aimed at the creation of synthetic varieties, clonal genotypes should be used, which, along with the complex of economically valuable traits, are distinguished by a high overall combining ability. It is recommended to use synthetic alfalfa of sowing Radoslaw in clean and mixed crops with other perennial herbs for production of high-quality forages in the soil-climatic zones of Polissya and Forest-steppe.
 Keywords: Medicago sativa L., clone, synthetic variety, dry matter, seeds.

Development and Evaluation of Sunflower Synthetic Varieties (Helianthus annuus L.)

Development and Evaluation of Sunflower Synthetic Varieties (Helianthus annuus L.)

CP-Elvia 3, new white maize variety resistant to tar spot complex for Mexican subtropical areas

En la producción de maíz, el agricultor se encuentra ante la alternativa de sembrar semilla comercial de maíz híbrido o de polinización libre, incluyendo variedades mejoradas o nativas. La semilla de maíz híbrido es costosa y es necesario comprarla en cada nuevo ciclo de siembra, mientras que una variedad mejorada de polinización libre ofrece varias ventajas ya que puede sembrarse por varios años, puede competir en rendimiento con los híbridos, es de menor costo y se difunde entre agricultores. Una variedad sintética ofrece ventajas adicionales sobre otras variedades incluyendo uniformidad en floración y fenotipo, mejor rendimiento de grano y resistencia a enfermedades. En éste trabajo se muestra la obtención de la variedad sintética de maíz de grano blanco CP-Elvia 3, con buen comportamiento agronómico y resistente al complejo de mancha de asfalto y que se obtuvo mediante un programa de selección recurrente de familias S1.

Partially inbred maize lines in topcrosses and hybrid performance

ABSTRACT In plant breeding programs, the selection of potential progenies in early generations of inbreeding is an essential step. Considering that, the adoption of topcrosses helps the breeder in the selection, this study aimed to verify the potential of S2 strains for synthesis of synthetic varieties and to obtain experimental information on yield and agronomic potential of topcross hybrids. As such, 75 topcross hybrids were generated from crossing 75 S2 lines with F2 generation of the commercial hybrid. The 75 hybrids were grown in a field, along with two commercial hybrids in a randomized complete block design with 4 replicates and in 4-meter plots. Flowering, plant height, height, diameter, length and weight in the ear, and grain yield traits were examined. Analysis of variance was performed, the combining ability was estimated, and, from the means, the Scott & Knott test was conducted. So, the topcross hybrids that distinguished themselves for grain yield were those composed by lines 67, 14, 44, and 69, presenting high CGA, therefore indicating good potential for producing synthetic or base population. For the other traits of agronomic interest that were assessed in maize, a potential for selection with different focuses was found: reduction of cycle and height and increase in length and diameter of the ear.

A method for obtaining flexible broccoli varieties for sustainable agriculture

BackgroundThe use of high inputs in agriculture resulted in few varieties (hybrids and pure lines) used in all agricultural systems. Also varieties of vegetables, including broccoli, for organic and low-input agriculture, are almost exclusively hybrids, since there are very few specific breeding programs and varieties for sustainable agriculture systems.A strategy to overcome this issue is the adoption of specific breeding programs for developing heterogeneous varieties (i.e. synthetics, open pollinated varieties, composite cross populations and mixtures). In fact, heterogeneous varieties are able to evolve and adapt to specific agro-climatic conditions.The aim of this study was to develop a method (an Evolutionary Breeding Program, EBP) for obtaining heterogeneous varieties of broccoli and test its efficiency in developing highly diverse varieties, as needed in sustainable agriculture.A synthetic variety originated from a landrace was multiplied in different environments for 3 cycles and morpho-phenological and genetic diversity of the derived populations were assessed.ResultsThe presented results are the first and unique indication about the efficiency of a short-time EBP for an allogamous species like broccoli.Few morphological changes were observed among varieties multiplied in different environments with different agro-climatic conditions. This could be probably due to the initial genetic diversity of the landrace from which the populations were selected and also to the great plasticity of the crop. However, SSR data highlighted a genetic differentiation among populations multiplied for two/three years across Europe and in Central Italy, that was not so evident when considering morphological data only.ConclusionsFew years of multiplication in different environments resulted in genetically differentiated broccoli populations that nonetheless preserved the original genetic diversity and productivity level and appear to evolve in relationship to different environments: the applied EBP is useful for developing heterogeneous materials for sustainable agriculture.

Rendimiento de forraje y composición morfológica de maíces nativos en condiciones semiáridas

Las condiciones ambientales en zonas semiáridas limitan la productividad de especies forrajeras empleadas en la alimentación animal; sin embargo, el maíz (Zea mays L.) presenta una amplia adaptación a diferentes condiciones ambientales de temperatura, precipitación, altitud, suelo entre otras. El objetivo del presente estudio fue evaluar el rendimiento y composición morfológica de diez genotipos de maíces nativos, un híbrido y una variedad sintética, durante el ciclo primavera-verano de 2017. Se utilizó un diseño experimental de bloques completos al azar y se realizó un análisis de varianza, las medias de los tratamientos se compararon con la prueba de Tukey. Las variables evaluadas fueron: rendimiento de materia seca total (MST) y por componente morfológico: hoja (MSh), tallo (MSt), mazorca (MSmz), panícula (MSp) y materia muerta (MSmm), altura de planta (AP), número de hojas (NH), longitud de hoja (LH), ancho de hoja (AH) y la relación hoja/tallo (H/T). El mayor y menor rendimiento de MST, lo obtuvo el genotipo Ratón×Tuxpeño Norteño y el híbrido A6-069-B, con 8 888 y 3 113 kg MS ha-1, respectivamente. La mayor altura (180 cm) la obtuvieron los genotipos Ratón×Tuxpeño Norteño y Olotillo×Tuxpeño. El mayor número de hojas lo presentó el genotipo Tuxpeño Norteño×Olotillo con 11.6. La mayor relación hoja/tallo (2.1) fue en la variedad sintética breve Padilla. Es necesario realizar más investigación en el mejoramiento por selección recurrente del genotipo Ratón×Tuxpeño Norteño para obtener un mayor rendimiento y valor nutritivo en el forraje de maíz.

Producción y calidad de grano y rastrojo en maíces en el altiplano poblano

La mayoría de las unidades de producción de rumiantes en los valles altos, en diversas regiones de México, integran al maíz como fuente de forraje. Este cultivo debe ser, por tanto, alto productor de grano y rastrojo de calidad. Con base en esto, el objetivo de la presente investigación fue evaluar el comportamiento de 36 genotipos de maíz en el altiplano de Puebla durante el año 2017. Los genotipos fueron siete híbridos comerciales, una variedad sintética, nueve poblaciones de polinización libre y diecinueve híbridos experimentales de cruza simple derivados de variedades locales. La siembra se realizó en tres experimentos con diseño látice 6x6 en unidades experimentales de dos surcos de 80 cm de ancho por cinco metros de largo. Se evaluaron variables relacionadas con características propias de las plantas y químicas del rastrojo producido. La principal variable discriminatoria fue rendimiento útil (RUT) que incluyó el rendimiento de grano (RGR) con la producción y digestibilidad del rastrojo. Los genotipos fueron diferentes (p< 0.001) en todas las variables medidas. En RUT, los genotipos sobresalientes fueron: HS-2®, Águila 215W®, SM-16 60x66, SM-16 5x64, SM-16 64x66, SM-16 53x64, SM-16 13x44, SM-16 23x60, SM-16 58x21, SM-16 44x64, SM-16 136x142, Niebla® y SM-16 21x64. No obstante, esta variable logra enmascarar genotipos que tienen producciones altas de grano y rastrojo, pero que tienen baja digestibilidad. Sólo el SM-16 5x64 tuvo superioridad en digestibilidad, pero rendimiento medio de materia seca de rastrojo, lo cual le da mayor potencial para ser un genotipo de doble propósito

Variability in a Silage Maize “Zea mays, L.” Base Population via Two Types of Families 3. Forage botanical composition and dry matter partitioning

The base population for the recent study which is a yellow seed synthetic variety of maize was provided by Dr. M. Abd El-Sattar Ahmed, professor of crop science, Crop Science Department, faculty of Agriculture, Egypt. Two types of families had formulated, as a step before selection for high yielding ability. Those were half-sib (H.S) families and the first generation of self-pollination (S1) families. Variability in the base population gene pool had estimated depending on vari-ance components of the families. Reduction in mean values associated with S1 families relative to half-sib families reached 0.182, 1.18, 0.98, 3.88, 2.75 and 5.72% for leaves percentage, stem percentage, ear percentage, grain percentage, cob per-centage and husk percentage, respectively. Genotypic variances among S1 families was larger in magnitude than the respec-tive value for half-sib families in each measured botanical composition and dry matter partitioning characters. Meanwhile, within family’s variance, (σ2f), environmental variances (σ2e) had reduced in S1 families relative to half-sib families in each measured character. Genotypic variation among half-sib and S1 families were less than 20% of the studied botanical compo-sition and dry matter partitioning characters mean values, except for cob percentage and husk percentage that had a genotyp-ic variation amount to 24% and 26%, respectively. The estimates of additive variance (δ2A) were positive for all studied botanical composition and dry matter partitioning characters. While, the estimates of dominance variance (δ2D) were nega-tive for all characters, the ratio of δ2A/δ2G indicated that additive genetic variance was more effective in controlling all stud-ied botanical composition and dry matter partitioning characters. Estimates of heritability were higher in magnitude when calculated from first selfing generation (S1) compared to half-sib families, for all studied characters. Stem percentage ex-pressed the least estimate heritability among all studied characters in each family type (0.798 and 0.414 for half-sib and S1 families, respectively). This might indicate the influence of environment in the expression of that character. Meanwhile husk percentage had highest genetic control expressed on heritability estimates from the two studied types of families.

Variability in Forage yield of a Silage Maize “Zea mays, L.”Base Population via Two Types of Families

The base population for the recent study which is ayellow seed synthetic variety of maize was provided by Dr. M. Abd El-Sattar Ahmed, professor of crop science, Crop Science Department, faculty of Agriculture, Egypt.Two types of families had formulated, as a step before selection for high yielding ability. Those were half-sib (H.S) fami-lies and the first generation of self-pollination(S1) families. Variability in the base population gene pool had estimated depending on variance components of the families. The ratio of σ2A/ σ2G indicated that, additive genetic variance was more effective in controlling green and dry forage yield. This might indicate the importance of additive genetic vari-ance in maize population, consequently, selection among inbred- progeny would expect to be superior to other meth-ods under most genetic situations. Reduction in mean values of forage yield associated with selfing, reached 0.62 and 0.57 for green forage yield (Kg/ plot) and dry forage yield (Kg/plot), respectively. Values of genotypic variances estimated from S1 families were of larger magnitude amounted to 1.63 and 1.94 times the corresponding values for half- sib families in green forage yield and dry forage yield. Opposite to that, environmental variance estimates from S1 families were 0.56 and 0.55 of the respective values from half- sib families in green forage yield and dry forage yield respectively.Genotypic variations in term of coefficient relative to the overall mean of green yield and dry yield were less than 20%of the character mean when estimated from half-sib and S1 families (10.85 vs. 13.96 and 10.21 vs. 14.31% for green and dry forage, respectively).Dry forage yield expressed the highest estimates of heritability in both family types (0.829 and 0.877 for half –sib and S1 families, respectively). While, the obtained values for green forage yield were of lower magnitude (0.53 and 0.67 for half-sib and S1 families, respectively). This might indicate addition-al environmental influences with green forage yield.

Exact inbreeding coefficient of maize synthetic varieties derived from mixed lines and single crosses

Abstract There is an apparent overvaluation in the inbreeding coefficient (IC) formula for a synthetic variety (SV) derived from a mixture of S single crosses and L lines (FSynL,SC) in Zea mays. Therefore, our goal was to derive the exact and general FSynL,SC. For the development of this SV (SynL,SC), an even number of L + 2S unrelated lines whose IC was F (0 ≤ F ≤ 1) was considered. We show that the exact and general formula for FSynL,SC is: FSynL,SC = (2L + S)(1 + F)/[4(L + S)2], and that the ICs and genotypic means of two additional synthetics developed from the same lines (one derived from (L + 2S)/2 single crosses and the other derived from the L + 2S lines) must be equal. Among these three SVs, SynL,SC shows the largest IC.

CP-Hilda 2, new yellow grain synthetic maize (Zea mays) variety resistant to horse´s tooth (Claviceps gigantea) for the Mexican highlands

En producción de maíz, la semilla de variedades de polinización libre ofrecen al agricultor obtener un precio más bajo que la semilla de híbridos comerciales, no es necesario comprar semilla nueva cada año, por su estabilidad genética puede sembrarse varios años, ofrecen más estabilidad en rendimiento de grano y tipo de planta, es más fácil de conseguir, puede competir en rendimiento con un híbrido y puede propagarse entre agricultores. El presente trabajo es resultado de actividades desarrolladas para la obtención de la variedad sintética de maíz de endosperma amarillo CP-Hilda 2, con buen comportamiento agronómico y resistencia genética a la enfermedad “diente de caballo”, siguiendo un programa de selección recurrente con líneas S1.

CP-Vero 1, white maize (Zea mays) synthetic variety resistant to head smut (Sporisorium reilianum f. sp. zeae) for Mexican highlands

En la producción de maíz, el agricultor se encuentra ante la alternativa de sembrar semilla comercial de maíz híbrido o semilla de polinización libre incluyendo variedades mejoradas o poblaciones nativas. La semilla de maíz híbrido tiene un alto costo, es necesario comprar semilla nueva para cada siembra mientras que la semilla de una variedad mejorada puede sembrarse por varios años, puede competir en rendimiento con un híbrido, es de bajo costo y puede compartirse entre agricultores. Una variedad sintética ofrece ventajas adicionales sobre una variedad mejorada común, con buen rendimiento de grano y uniformidad en floración y fenotipo. Este trabajo presenta actividades involucradas en la obtención de la variedad sintética de maíz de endospermo blanco CP-Vero 1 siguiendo un programa de selección recurrente de líneas S1 para obtener buenas características agronómicas y resistencia al carbón de la espiga.

Селекция синтетических сортов подсолнечника: особенности, направления и возможные перспективы (обзор)

Селекция синтетических сортов подсолнечника: особенности, направления и возможные перспективы (обзор)

General inbreeding coefficient of maize synthetics derived from three-way line hybrids

The scarcity of pure and unrelated maize inbred lines that possess high combining ability in Mexico has led breeders wishing to form single crosses to develop double-cross or three-way line hybrids (TWLHs) instead. However, some of the farmers who grow these hybrids cultivate their advanced generations later on. Although the resulting populations can be viewed as the synthetics that the random mating of the parental lines (SynL) of these hybrids would produce, there may be differences. The synthetic variety whose parents are t TWLHs (SynT) is interesting because the contributed gene frequencies of the three lines that are parents of a TWLH are not balanced and this may generate a difference between the inbreeding coeff icients (ICs) of the SynL and SynT. Since an unbiased and general inbreeding coeff icient of the SynT and a prediction formula for the SynT genotypic mean (GM) are not yet known, the objective of this study was to derive formulae for these two important parameters of SynT. To form the t TWLHs, it was assumed that 3t unrelated lines whose IC was F (0 ≤ F ≤ 1) were used. Unbiased and general formulae for FSynT and GM were derived for the f irst time. In particular, it was found that FSynT = [3(1 + F)]/(16t). Since the inbreeding coeff icient of the SynL derived from the same 3t lines is (1 + F)/(6t), then FSynT > FSynL. These f indings suggest that the genotypic mean of the SynL grain yield is larger than the SynT’s.

RENDIMIENTO DE GRANO EN MAÍCES ADAPTADOS A CONDICIONES DE LA BAJA CUENCA DEL PAPALOAPAN

<p>In humid tropical zones of Mexico maize (<em>Zea mays</em> L.) is an important crop in human and animal feed. Six maize genotypes were studied to evaluate grain and leaf production, under three plant densities (50,000; 62,500 and 83,333 plants ha<sup>-1</sup>). The assay was carried out at the Papaloapan University Campus Loma Bonita, Oaxaca. Genotypes used were: DK-357, HE-1A17, H-520, NH5, H-564C and the synthetic variety VS-536. Experimental design consisted of a randomized blocks. Each experimental plot was 12.8 m<sup>2</sup>. Variables studied were: plant height (cm), days to male flowering, days to silking, ear weight (g), ear length (cm), number of grains per ear, weight of a hundred grains (g), grain yield (kg ha<sup>-1</sup>), and dry leaf yield (kg ha<sup>-1</sup>). An analysis of variance was performed for genotypes, densities, and genotypes by densities interaction. In addition, a Tukey test for pairwise comparison was run (P<em> </em>≤ 0.05). There were significant differences among genotypes, densities and genotype by density interactions. The hybrid H-520 produced the highest grain yield (5,993.3 kg ha<sup>-1</sup>). The synthetic variety VS-536 showed higher leaf yield than anyone else.</p>