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Search Results: 1 - 10 of 324 matches for " Heterosis "
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Recent Advances in Understanding Plant Heterosis  [PDF]
Shouqian Feng, Xiaoliu Chen, Shujing Wu, Xuesen Chen
Agricultural Sciences (AS) , 2015, DOI: 10.4236/as.2015.69098
Abstract: Although heterosis is widely utilized in crop production, its genetic and molecular basis is still elusive. It is arguably that heterosis arises in crosses between genetically and/or epigenetically distinct individuals. Various genetic models have been proposed to explain heterosis, such as dominance and overdominance hypothesis. With the recent advancements in functional genomics, epigenetics, transcriptomics, proteomics, and metabolomics-related technologies, systems-level approaches have been adopted to understand the molecular basis of heterosis. In this review, we gather a brief account of findings from various studies in order to better understand the genetic and molecular basis of heterosis.
Hybrid Vigour and Genetic Control of Some Quantitative Traits of Tomato (Solanum lycopersicum L.)  [PDF]
Chinedozi Amaefula, Christian U. Agbo, Godson Emeka Nwofia
Open Journal of Genetics (OJGen) , 2014, DOI: 10.4236/ojgen.2014.41005

Parental lines, F1 generation of domesticated tomato (Solanum lycopersicum L.) and Lycopersicon pimpinellifolium L. were evaluated at Department of Crop Science, University of Nigeria, Nsukka for improvement in their quantitative traits. The experiment was laid out in a randomized complete block design with three replications. Data were collected on the quantitative traits and fruit yield. Better Parent Heterosis (BPH), genetic variances, gene effects and heritability of the traits were estimated for the hybrids. BPH result showed that the Wild × Petomech cross had the highest positive BPH of 358.36% in fruit yield. The highest negative BPH of -95.59% was recorded for the hybrid, Wild × Grosso in average fruit weight while the hybrid, Insulata × Grosso had the lowest negative BPH of -16.27% in average fruit weight. Additive gene action and additive × additive gene action (aa) were significantly in control of three crosses, W × P, W × In and W × G in fruit yield. Additive variance was higher than dominance variance in fruit yield for all the hybrids with wild as one of its parents. Again, hybrids with wild as one of its parent as, W × G, W × In, and W × P had the highest narrow sense heritability in fruit yield (59.15%, 51.69%, 59.88%, respectively). High level of epistasis controlled some of the quantitative traits and hybridization evidenced by the result was effective in developing new tomato cultivars with positive heterotic effects in fruit yield.

The Physiological Basis of Heterosis for Potassium Uptake of Hybrid Millet  [PDF]
Zihui Liu, Binhui Liu, Hongmei Zhang, Guoliang Li, Yanmin Zhang, Xiulin Guo
American Journal of Plant Sciences (AJPS) , 2014, DOI: 10.4236/ajps.2014.513215

Hybrid millet Zhang and its parental cultivars were studied for their potassium (K) uptake and accumulation characteristics and related physiological mechanisms. Hydroponic culture was performed with two K levels (i.e., high and low) set up. At high K level, hybrid millet showed heterobeltiosis in K accumulation and leaf K content, and it also had higher H+-ATPase activity, respiration rate, root oxidant activity and root K+ influx rate than its parental cultivars. All these lay the physiological foundation of heterosis for potassium uptake of hybrid millet. At low K level, the hybrid millet had a lower H+-ATPase activity and a higher K efflux rate than its parental cultivars, thus heterobeltiosis in K accumulation or leaf K content was not observed. Therefore, high level K fertilizer application is recommended for hybrid millet cultivation as it is favorable for hybrid millet to display heterosis in K uptake and K accumulation.

Heterosis and Combing Ability in F1 Population of Hexaploid Wheat (Triticum Aestivum L.)  [PDF]
Fahad Ali Kalhoro, Asghar Ali Rajpar, Shahmir Ali Kalhoro, Amanullah Mahar, Amjad Ali, Sohail Ahmed Otho, Rab Nawaz Soomro, Fayaz Ali, Zulfiqar Ali Baloch
American Journal of Plant Sciences (AJPS) , 2015, DOI: 10.4236/ajps.2015.67107
Abstract: The heterosis, heterobeltiosis, general combining ability (GCA) and specific combining ability (SCA) were examined during Rabi (crop season) of 2013-2014 in hexaploid wheat genotypes. The experiment for this study was conducted at the Botanical Garden, Department of Plant Breeding & Genetics, Sindh Agriculture University Tandojam, Pakistan. The breeding material was comprised of four parents (Imdad, TD-1, SKD-1, and Moomal). These parents were crossed in half partial mating fashion; thus, six possible cross combinations (F1s) were obtained (Imdad × TD-1, Imdad × SKD-1, Imdad × Moomal, TD-1 × SKD-1, TD-1 × Moomal, and SKD-1 × Moomal). A three-replicated RCB Design was used. The mean squares corresponding to different traits of various hexaploid wheat genotypes indicated significant (P < 0.01) GCA (parents) and SCA (F1 hybrids) effects for the characters (plant height, tillers plant-1, spike length, spikelets spike-1, seeds spike-1, seed index, and grain yield plant-1). The mean performance of F1 hybrids differed significantly (P < 0.01) for all the traits studied. Among the parents, Imdad and TD-1 proved to be better general combiners for almost all the studied traits. In regards to SCA effects, the F1 hybrids Imdad × TD-1 and Imdad × SKD-1 expressed higher SCA and heterotic effects for most of the studied traits.
Evaluación de la heterosis y heredabilidad en híbridos cubanos de tomate (Solanum lycopersicum)
Rodríguez,C. J; álvarez,Marta; Moya,C; Plana,Dagmara; Due?as,F; Lescay,E; Rodríguez,S;
Cultivos Tropicales , 2008,
Abstract: the characters of yield and its components were evaluated in tomato f1 hybrids, obtained through two statistical genetic designs (top cross and biparental) and their progenitors, seeded within the optimal crop season (october 15-december 20, 2006) at the national institute of agricultural sciences. the experiment was performed in asbestos cement gutters with a microjet irrigation system under organoponic conditions. the percentage of heterosis and narrow-sense heritability was estimated. the study of heterosis enabled to identify those hybrids showing a better behavior than their cultivars of origin, regarding many important characters for the producer, reaching the highest yield values at the top cross, and yield as well as fruit number at the biparental one. every character showed high values of heritability, except yield per plant with mean values.
Quantifica??o e método para sele??o de plantas nucelares de Poncirus trifoliata
Oliveira, Roberto Pedroso de;Scivittaro, Walkyria Bueno;Radmann, Elizete Beatriz;
Pesquisa Agropecuária Brasileira , 2003, DOI: 10.1590/S0100-204X2003001000006
Abstract: the aim of this work was to quantify the percentage of zygotic and nucellar plants of poncirus trifoliata (l.) raf. in an open pollinated population, and to evaluate the efficiency of the morphology and vigor-based selection method of nucellar plants. seeds from mature fruits were sowed in plastic tubes of 50 cm3. after 150 days the plants were transferred to plastic bags of 4,8 dm3. leaf morphology and height of plants were evaluated 300 days after sowing. genetic characterization was carried out by isoenzymatic systems. in average, 1.07 plants were obtained per seed and the maximum value was two plants per seed. in these cases, both plants were characterized as nucellar by isoenzymes, although showing different and smaller size than the average of the rest of the plants. zygotic plants identified were 5.9% of the population and were distributed in the classes of smaller size, showing genetic depression. plants showing hybrid vigor were not observed. the differentiation of nucellar from zygotic plants was not possible by leaf morphological characters. the visual elimination of the smaller plants, about 30% of the population, is an efficient method to select trifoliata nucellar plants produced in plastic tubes under protected environment.
Efeito da heterose na qualidade de sementes de milho doce
Reis, Luciléa Silva dos;Pereira, Messias Gonzaga;Silva, Roberto Ferreira da;Meireles, Robson Celestino;
Revista Brasileira de Sementes , 2011, DOI: 10.1590/S0101-31222011000200013
Abstract: the objective of this study was to evaluate the physiological seed quality of selected sweet corn genotypes and their relationship to heterosis. fourteen sweet corn genotypes developed by the universidade estadual do norte fluminense darcy ribeiro were used. the genotypes were multiplied in campos dos goytacazes through controlled pollination to ensure genetic purity. the physiological quality was evaluated using germination and vigor tests, including: first germination count and seedling classification and emergence in sand. results showed that the seeds with sweet endosperm were less vigorous than those with common endosperm. the sweet endosperm seeds of parental genotypes adapted to the region were more vigorous than those of non-adapted parents. heterosis was observed for all germination and vigor traits in hybrid seeds when compared to their parents. results indicate that hybrid development has an excellent potential for obtaining strong and more vigorous sweet corn seeds.
Carcass quality of crossbred steers with different degrees of zebu blood in the genotype: meta-analysis
Venturini, Tiago;Menezes, Luís Fernando Glasenapp de;Kuss, Fernando;Martin, Thomas Newton;Vonz, Douglas;Paris, Wagner;
Revista Brasileira de Zootecnia , 2011, DOI: 10.1590/S1516-35982011001100041
Abstract: in order to evaluate the effect of the different percentages of zebu blood in the genotype of crossbred steers on carcass traits, a meta-analysis was carried out, using 30 studies conducted in brazil that have been published since the year 2000. the parameters evaluated were hot carcass weight (221 estimates), cold carcass weight (232), hot carcass (236) and cold carcass yield (223), subcutaneous fat thickness (238) and the percentages of saw cut (233), forequarter (234) and sidecut (246 estimates). initially, exploratory analysis was performed for each of the variables for detection of publication vices through the dispersion of observations by pointing out the outliers eliminated. normality tests were normal and the data were subjected to analysis of variance for the regression study, which were assessed to the third degree. weights of hot carcass and cold carcass, hot and cold carcass yield and the percentage of saw cut had a quadratic effect on animals with the presence of zebu blood, indicating superiority of crossbred animals. the regression equation showed that 66; 50; 72; 81 and 59% of zebu in crossbred animals showed higher hot and cold carcass weight, hot and cold carcass percentage and saw cut, respectively. fat thickness was not influenced by the degree of zebu in the genotype. the percentage of forequarter has a positive response by increasing the degree of zebu in the genotype, while the sidecut has a negative answer. the crossbreeding between zebu and european breeds provides carcasses with better quality than purebred animals.
Aptitud combinatoria del rendimiento de antocianinas y de características agronómicas en poblaciones nativas de maíz pigmentado
Espinosa Trujillo, Edgar;Mendoza Castillo, Ma. del Carmen;Castillo González, Fernando;Ortiz Cereceres, Joaquín;Delgado Alvarado, Adriana;
Revista fitotecnia mexicana , 2010,
Abstract: the red, blue and purple maize (zea mays l.) kernels contain anthocyanins of importance in the human diseases prevention. nowadays, the selection of maize based on kernel color is considered relevant. to define efficient selection methodologies is convenient to apply genetics designs that allow analyzing the genetic contribution on the quantitative variation in the traits of interest. a genetic design was used to estimate general (gca) and specific (sca) combining abilities, maternal (me) and reciprocal (re) effects of the anthocyanin concentrations per unit of weight of grain (ackg) and the anthocyanin yield per hectare (ayha). an experiment of diallel crosses between five native populations with different grain color was established where some agronomic traits were measured. in another experiment, f2 seed was obtained using controlled pollination, to determine the concentrations of anthocyanin in the whole grain. using data from both experiments the anthocyanins yield per plant (aypta), per hectare (ayha) and the heterosis (%) were calculated. there was similarity among progenitors in the agronomic traits, but they differed on their capacity to accumulate anthocyanin. the gca effects were superior in most of the agronomic traits compared to the sca. the aypta had significant effects of gca, sca and re, being the red-1 population the one of greater gca. there was heterosis in crosses for ackg, where the best ones were red-1 × red-2, red-1 × blue-1 and red-1 × blue-2; and for ayha the best crosses were red-1 × red-2 and red-1 × blue-2.
Study on Genetic Variability and Heterosis in Potato
M.K. Biswas,M.A.A. Mondal,M.G. Ahmed,A. Hoque
Pakistan Journal of Biological Sciences , 2005,
Abstract: Genetic variability and heterosis for eight quantitative traits were evaluated in seven parents and ten hybrids. The hybrids were derived from a 5x2 line x tester mating design. In general high component of variation and coefficient of variability were observed for most of the characters. The highest component of variation, coefficient of variability and heritability were noticed in PW, TW 60 and TN 60. Characters those with high genetic variability and genetic advance were considered to be important for selecting the desirable parents. Heterosis was worked out over mid parent, better parent and standard parent. Combinations AU/13, LP/13, PT/13 and LS/13 for PH; combination PT/13 and LP/13 for TN 60 were significant for mid parent, better parent and standard parent heterosis. The best heterotic combinations for TW 60 were LP/13, LS/13 and LSB/13 which recorded 990.28, 1115.28 and 648.61% standard heterosis respectively and can be utilized for hybrid development.
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