El maíz puede ser utilizado como materia prima en la obtención de bioetanol. Para iniciar un programa de mejora es relevante conocer el comportamiento para el rendimiento de etanol por unidad de peso ...de grano (RE) de híbridos F1 en base al de sus líneas progenitoras y su heredabilidad (h2). Se evaluaron 5 líneas endocriadas desarrolladas por INTA Pergamino y sus híbridos simples a los cuales se les midió el rendimiento de etanol (ml/gr) mediante NIRs sobre muestras de grano obtenidas previa polinización controlada para evitar efecto de xenia. El experimento siguió un diseño de bloques completos aleatorizados, con 2 repeticiones en 3 ambientes, Pergamino (P), Junín (J) y Colón (C) en la campaña 2015/16. El análisis de varianza a través de localidades mostró diferencias significativas para la interacción genotipo×ambiente y genotipos. Se estimaron las h2 mediante una regresión padre-progenie por localidad y a través de localidades. La h2 a través de los ambientes fue de 0,53, mientras que fue de 0,71, 0,68 y 0,37 para P, J y C, respectivamente. Además se evaluaron los niveles de heterosis promedio (Het), encontrando un rango de 2,6-6,0%. Se encontró una asociación positiva entre la Het y el RE. El estudio de la Het permitió identificar híbridos que mostraron un mayor RE que sus progenitores en todos los ambientes. Los altos valores de h2 encontrados por localidad, comparados con la h2 intermedia a través de localidades, podrían estar sobreestimados al haber interacción genotipo×ambiente. Se pudo establecer que existiría variancia aditiva potencialmente disponible para el RE.
Current model used in the calculation of genetic parameters and genetic evaluation of the Hispano-Arabe horse breed takes into account several effects, one of which are the blood levels, defined as ...the genetic proportions of the Arab breed in each individual. We believe that this particularity means that there are some differences in the estimation of genetic parameters and breeding values caused by dominance effects. The use molecular tools to estimate the percentage of blood is pointed out in this study. We used the multilocus genotypes of 22 microsatellites in a sample of 114 HÁ horses using as reference populations 48 PRE and 60 PRÁ as well as out-group 46 PSI. Through a statistical analysis procedure we develop individual test to assign horses HA to PRE and PRA populations. The results show as 48% of the animals to HA breed were assigned to PRE (48.60 ±0.26), 45% of the animals to breed PRA (48.76±0.27) and 7% to PSI breed.
El caballo Hispano – Árabe (HÁ) es fruto del cruzamiento dirigido de dos razas, el Pura Raza Español (PRE) y Pura Raza Árabe (PRÁ) y por esta particularidad pueden existir diferencias entre individuos en cuanto al porcentaje de sangre española y árabe. La asignación actual del porcentaje de sangre se realiza teniendo en cuenta la genealogía de los individuos, pero pueden existir errores de estimación, principalmente por el desconocimiento del pedigrí completo de los animales en registro auxiliar. Utilizando marcadores moleculares (microsatélites) se plantea utilizar una herramienta estadística para medir de una manera exacta este porcentaje de sangre de los animales y poder utilizar este parámetro como un dato fiable más a tener en cuenta en la evaluación genética de los reproductores de la raza. Para ello se han utilizado los genotipos multilocus de 22 microsatélites sobre una muestra de 114 caballos HÁ, utilizando como poblaciones de referencia 48 PRE y 60 PRÁ además de 46 Pura Sangre Ingles como outgroup. A través de un procedimiento estadístico se realiza un análisis de Asignación a nivel individual para asignar los caballos HÁ a las poblaciones PRE y PRÁ. Los resultados encontrados muestran como el 52% de los animales HÁ se asignan a la raza PRE (48,60±0,26) y el 48% de los animales a la raza PRÁ (48,76±0,27).
Paspalum dilatatum Poir. es una gramínea perenne apomíctica y pentaploide sudamericana de alto interés forrajero, pero su baja producción de semilla, reproducción apomíctica y susceptibilidad a ...Claviceps paspali limitan su domesticación y mejoramiento. Se conocen cinco especies o biotipos tetraploides sexuales muy cercanamente emparentados con P. dilatatum. Estos biotipos mayormente autógamos pueden hibridarse en diferentes combinaciones. Para explorar el potencial productivo de combinar germoplasma de diferentes fuentes tetraploides, se realizó un cruzamiento entre dos de estos biotipos: P. dilatatum subsp. flavescens y P. dilatatum "Virasoro". Ambos biotipos presentan particular interés por su productividad y baja infección por Claviceps. Pueden cruzarse fácilmente y generar híbridos fértiles. Se comparó el híbrido F1 con los padres y 20 familias F3 para determinar la presencia de heterosis, estimar la variabilidad genética aditiva y el grado de segregación transgresiva esperada para varias características morfológicas y productivas. De las características analizadas, peso seco y número de inflorescencias mostraron en la F1 valores superiores al mejor de los padres. En la generación F3 se observó segregación transgresiva en más del 30% de las familias para cinco de las ocho características analizadas además de altos valores de varianza genética aditiva estimada. Estos resultados muestran que por lo menos en algunas combinaciones, la hibridación entre diferentes biotipos tetraploides genera recombinantes vigorosos y productivos con un alto potencial de producir segregantes transgresivos promisorios. Esta estrategia de mejoramiento resulta altamente promisoria. Se están evaluando las líneas recombinantes avanzadas y nuevas combinaciones además de la variabilidad presente dentro de cada biotipo.
The present investigation was undertaken with an objective to study the magnitude of heterosis involved in 32 hybrids obtained by crossing four (female) x eight (male) genotypes in L x T fashion ...along with their 12 parents and two standard checks (JLT-408 and PRACHI) evaluated during summer, 2019-20 at Oilseeds Research Station, Latur. Data were recorded on yield and its different contributing traits. The analysis of variance for experimental design revealed significance differences among the parents, hybrids and parents vs hybrids for most of the characters indicated the presence of genetic variability among the experimental material. The crosses viz., SWETHA x V-25, V-34 x TBS-12, V-32 x TBS-7, SWETHA x R-26 and SWETHA x TBS-12 found with high heterobeltiosis and standard heterosis over check JLT-408 and PRACHI for seed yield along with other yield contributing traits. Significant heterobeltiosis and standard heterosis for seed yield were observed for the majority of yield and yield attributing traits. Selection of high heterotic hybrids with high per se performance would be reliable in the improvement of sesame.
Plant architecture is the key factor affecting overall yield in many crops. The genetic basis underlying plant architecture in rapeseed (Brassica napus), a key global oil crop, is elusive. We ...characterized an ethyl methanesulfonate (EMS)-mutagenized rapeseed mutant, sca, which had multiple phenotypic alterations, including crinkled leaves, semi-dwarf stature, narrow branch angles and upward-standing siliques.
We identified the underlying gene, which encodes an Aux/IAA protein (BnaA3.IAA7). A Gto-A mutation changed the glycine at the 84th position to glutamic acid (G84E), disrupting the conserved degron motif GWPPV and reducing the affinity between BnaA3.IAA7 and TIR1 (TRANSPORT INHIBITOR RESPONSE 1) in an auxin dosage-dependent manner. This change repressed the degradation of BnaA3.IAA7 and therefore repressed auxin signaling at low levels of auxin that reduced the length of internodes. The G84E mutation reduced branch angles by enhancing the gravitropic response.
The heterozygote +/sca closely resembled a proposed ideal plant architecture, displaying strong yield heterosis through single-locus overdominance by improving multiple component traits.
Our findings demonstrate that a weak gain-of-function mutation in BnaA3.IAA7 contributes to yield heterosis by improving plant architecture and would be valuable for breeding superior rapeseed hybrid cultivars and such a mutation may increase the yield in other Brassica crops.
En el tomate (Solanum lycopersicum L.) los cruzamientos intervarietales se utilizan para explotar la heterosis a nivel comercial y los interespecíficos para introgresar genes al cultivo. En cruzas ...con las especies silvestres, el genotipo cultivado generalmente actúa como progenitor femenino por el mayor tamaño de sus flores que facilita la emasculación; mientras que en la producción de híbridos comerciales, el progenitor masculino es aquel que produce más polen. Los efectos recíprocos (ER) son el cambio en el valor medio de un carácter cuantitativo en el híbrido al invertir el rol sexual de los progenitores de un cruzamiento. En su determinación están involucrados mecanismos genéticos tales como el efecto materno, la herencia citoplasmática y el imprinting genómico. Al analizar cinco cultivares y sus combinaciones híbridas se detectaron efectos heteróticos y recíprocos, así como herencia parental en caracteres del fruto. En un subconjunto de cruzamientos, mediante MSAP (Methylation Sensitive Amplified Polymorphism), se observó que la metilación del ADN podría ser una de las causas de los ER encontrados en los híbridos. Al extender el análisis de los ER en las generaciones F2 en un cruzamiento interespecífico se comprobó su existencia para la vida poscosecha y el tamaño de los frutos a nivel fenotípico y molecular. Nuestros resultados justifican la importancia en la elección del progenitor femenino al realizar los cruzamientos y la necesidad de indagar el efecto de factores epigenéticos sobre caracteres de producción según la dirección de los mismos.
The present investigation on heterosis and inbreeding depression in wheat was carried out at the Crop Research Farm of CSAUA&T, Nawabganj, Kanpur, U.P., India, during the Rabi crop season 2019-20. A ...ten parental half-diallel cross comprising of 45 F1s and 45 F2s together with parents was grown in three replications. The outcome of better parent heterosis revealed that the cross combinations, namely, HD3086 x HD-2733, HD3086 x K0307, HD3086 x HD2967, HD3086 x K1601, and HD2967 x K0402 exhibited positive and high heterosis for grain yield. In the case of economic heterosis over the check (HD2967), the cross combination viz. HD3086 x K0307, HD3086 x HD2967, HD-967 x K0402, HD2967 x K1601, and HD2967 x K1314 exhibited significant and positive heterosis for grain yield. Inbreeding depression for grain yield ranged from 1.51 (DH 29767 x K 8962) to 8.95 (DBW 88 x K 8962) percent. For grain yield, out of the 45 crosses, all combinations exhibited significant and positive inbreeding depression in F2. The cross combinations may be used to increase grain yield and to produce better transgressive segregants for future breeding programs to maintain the specific gene pool of bread wheat.
SUMMARY
Plant height (PH) is an important trait affecting the plant architecture, seed yield, and harvest index. However, the molecular mechanisms underlying PH heterosis remain unclear. In addition, ...useful PH‐related genes must be urgently identified to facilitate ideal plant architecture breeding in rice (Oryza sativa L.). In the present study, to explore rice quantitative trait loci (QTLs) and heterosis‐related loci of PH in rice, we developed a high‐generation (>F15) population of 272 recombinant inbred lines (RIL) from a cross of two elite varieties, Luohui 9 (indica/xian) × RPY geng (japonica/geng), and two testcross hybrid populations derived from the crosses of RILs and two cytoplasmic male sterile lines (YTA indica and Z7A japonica). Using deep resequencing data, a high‐density genetic map containing 4758 bin markers was constructed, with a total map distance of 2356.41 cM. Finally, 31 PH‐related QTLs for different PH component lengths or tiller numbers across five seasons were identified. Two major environment‐specific PH QTLs were stably detected in Hainan (qPH‐3.1) or Hubei (qPH‐5.1), which have undergone significant functional alterations in rice with changes in geographical environment. Based on comparative genomics, gene function annotation, homolog identification, and existing literature (pioneering studies), candidate genes for multiple QTLs were fine‐mapped, and the candidate genes qPH‐3.1 and qPH‐5.1 for PH were further validated using CRISPR–Cas9 gene editing. Specifically, qPH‐3.1 was characterized as a pleiotropic gene, and the qPH‐3.1 knockout line showed reduced PH, delayed heading, a decreased seed setting rate, and increased tiller numbers. Importantly, 10 PH heterosis‐related QTLs were identified in the testcross populations, and a better‐parent heterosis locus (qBPH‐5.2) completely covered qPH‐5.1. Furthermore, the cross results of fixed‐genotype RILs verified the dominant effects of qPH‐3.1 and qPH‐5.1. Together, these findings further our understanding of the genetic mechanisms of PH and offer multiple highly reliable gene targets for breeding rice varieties with ideal architecture and high yield potential in the immediate future.
Significance Statement
In the present study we constructed a high‐density genetic map containing 4758 bin markers of a high‐generation recombinant inbred line population from a cross of two elite rice (Oryza sativa L.) varieties, Luohui 9 (indica/xian) × RPY geng (japonica/geng). Two major environment‐specific QTLs of plant height were discovered and experimentally validated.
The mechanisms underlying heterosis have long remained a matter of debate, despite its agricultural importance. How changes in transcriptional networks during plant development are relevant to the ...continuous manifestation of growth vigor in hybrids is intriguing and unexplored. Here, we present an integrated high-resolution analysis of the daily dynamic growth phenotypes and transcriptome atlases of young
seedlings (parental ecotypes Col-0 and Per-1 and their F
hybrid). Weighted gene coexpression network analysis uncovered divergent expression patterns between parents of the network hub genes, in which genes related to the cell cycle were more highly expressed in one parent (Col-0), whereas those involved in photosynthesis were more highly expressed in the other parent (Per-1). Notably, the hybrid exhibited spatiotemporal high-parent-dominant expression complementation of network hub genes in the two pathways during seedling growth. This suggests that the integrated capacities of cell division and photosynthesis contribute to hybrid growth vigor, which could be enhanced by temporal advances in the progression of leaf development in the hybrid relative to its parents. Altogether, this study provides evidence of expression complementation between fundamental biological pathways in hybrids and highlights the contribution of expression dominance in heterosis.
To study the combining ability, gene action and heterosis, eighteen intra-hirsutum cotton hybrids were developed by crossing three lines (females) and six testers (mlaes) in line × tester design ...during Kharif 2021 at Regional Agricultural Research Station, ANGRAU, Lam, Guntur. The analysis of variance revealed significant variability among the experimental material for seed cotton yield, lint yield, and fibre quality traits. The non-additive gene action was observed for traits namely, ginning out turn, seed cotton yield, lint yield, and fibre quality traits while the upper half mean length and uniformity index exhibited preponderance of additive gene action. Among the parents, TCH 1837 (Line) and Lam GPC 274 (Tester) were identified as the best general combiners for the traits, bundle strength and elongation while the lines, SCS 1207, GISV 298, and tester Lam GPC 235 were identified as the best combiner for ginning out turn, seed cotton yield, and lint yield. The F1 hybrids viz., TCH 1837 / Lam GPC 117, GISV 298 / Lam GPC 274, and GISV 298 / Lam GPC 51 were identified as the best hybrids and these could be used for exploitation through heterosis breeding as these hybrids exhibited significant per se performance, high positive SCA effects and better parental heterosis for the said characters. The cross combinations namely, GISV 298 / Lam GPC 235 and SCS 1207 / Lam GPC 355 possessed significantly high GCA effects for the parents and non-significant SCA effects for the corresponding hybrids for important yield components and fibre quality traits. Hence, these could be exploited in recombination breeding for improvement of yield and other fibre quality traits in cotton.
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