Sorghum production is affected by a wide array of biotic constraints, of which sorghum shoot fly, Atherigona soccata is the most important pest, which severely damages the sorghum crop during the ...seedling stage. Host plant resistance is one of the major components to control sorghum shoot fly, A. soccata. To understand the nature of gene action for inheritance of shoot fly resistance, we evaluated 10 parents, 45 F1's and their reciprocals in replicated trials during the rainy and postrainy seasons. The genotypes ICSV 700, Phule Anuradha, ICSV 25019, PS 35805, IS 2123, IS 2146, and IS 18551 exhibited resistance to shoot fly damage across seasons. Crosses between susceptible parents were preferred for egg laying by the shoot fly females, resulting in a susceptible reaction. ICSV 700, ICSV 25019, PS 35805, IS 2123, IS 2146, and IS 18551 exhibited significant and negative general combining ability (gca) effects for oviposition, deadheart incidence, and overall resistance score. The plant morphological traits associated with expression of resistance/susceptibility to shoot fly damage such as leaf glossiness, plant vigor, and leafsheath pigmentation also showed significant gca effects by these genotypes, suggesting the potential for use as a selection criterion to breed for resistance to shoot fly, A. soccata. ICSV 700, Phule Anuradha, IS 2146 and IS 18551 with significant positive gca effects for trichome density can also be utilized in improving sorghums for shoot fly resistance. The parents involved in hybrids with negative specific combining ability (sca) effects for shoot fly resistance traits can be used in developing sorghum hybrids with adaptation to postrainy season. The significant reciprocal effects of combining abilities for oviposition, leaf glossy score and trichome density suggested the influence of cytoplasmic factors in inheritance of shoot fly resistance. Higher values of variance due to specific combining ability (σ(2)s), dominance variance (σ(2)d), and lower predictability ratios than the variance due to general combining ability (σ(2)g) and additive variance (σ(2)a) for shoot fly resistance traits indicated the predominance of dominance type of gene action, whereas trichome density, leaf glossy score, and plant vigor score with high σ(2)g, additive variance, predictability ratio, and the ratio of general combining ability to the specific combining ability showed predominance of additive type of gene action indicating importance of heterosis breeding followed by simple selection in breeding shoot fly-resistant sorghums. Most of the traits exhibited high broadsense heritability, indicating high inheritance of shoot fly resistance traits.
Testcross factorials in newly established hybrid breeding programs are often highly unbalanced, incomplete, and characterized by predominance of special combining ability (SCA) over general combining ...ability (GCA). This results in a low efficiency of GCA-based selection. Machine learning algorithms might improve prediction of hybrid performance in such testcross factorials, as they have been successfully applied to find complex underlying patterns in sparse data. Our objective was to compare the prediction accuracy of machine learning algorithms to that of GCA-based prediction and genomic best linear unbiased prediction (GBLUP) in six unbalanced incomplete factorials from hybrid breeding programs of rapeseed, wheat, and corn. We investigated a range of machine learning algorithms with three different types of predictor variables: (a) information on parentage of hybrids, (b) in addition hybrid performance of crosses of the parental lines with other crossing partners, and (c) genotypic marker data. In two highly incomplete and unbalanced factorials from rapeseed, in which the SCA variance contributed considerably to the genetic variance, stacked ensembles of gradient boosting machines based on parentage information outperformed GCA prediction. The stacked ensembles increased prediction accuracy from 0.39 to 0.45, and from 0.48 to 0.54 compared to GCA prediction. The prediction accuracy reached by stacked ensembles without marker data reached values comparable to those of GBLUP that requires marker data. We conclude that hybrid prediction with stacked ensembles of gradient boosting machines based on parentage information is a promising approach that is worth further investigations with other data sets in which SCA variance is high.
The current study involved the evaluation of 96 pearl millet hybrids synthesized by crossing eight lines with 12 testers using a Line x Tester mating design. The experiment was conducted during the ...Kharif season of 2022 with two replications and included standard checks COH10 and 86M38. Analysis of variance for combining ability revealed that, significant amount of variation was present in all hybrids for studied traits. The contribution of lines to the total variance in hybrid was greater than tester. The ratio between GCA and SCA variance was less than one for all traits and it showed that non additive gene action was predominant and highlighting the potential of heterosis breeding to exploit hybrid vigor. Among the parents, ICMB 02777 and PT 6679 were identified as good combiners, showing positive gca effects and high mean performance for grain yield, test weight, single earhead weight, and single earhead threshed weight. The other parents viz., ICMB 02444, ICMB 93222, PT 6067, and PT 6476 were also recognized as good combiners for grain yield. Out of the 96 hybrids, the cross ICMB 02777 x PT 6679 exhibited significant positive heterosis along with high standard heterosis over both checks for grain yield, test weight and single earhead threshed weight. Additionally, the crosses ICMB 02444 x PT 6679, ICMB 93222 x PT 6067 also recorded significant sca effect for grain yield per plant. These promising hybrid combinations hold great potential for heterosis breeding programs and may be suitable for commercial exploitation after thorough evaluation under multi-location trials.
The selection of soybean genotypes with seeds of high physiological quality is key to increasing the likelihood of establishment and success in the field and thus reaping higher yields. The aim of ...this study was to evaluate the genetic control of the physiological quality of soybean seeds from a partial diallel cross. Six previously selected soybean cultivars, group 1 (CD 201, CA 115, MS 8400) and group 2 (CD 202, Syn 1263, Syn 1279), were intercrossed by a partial diallel cross, totalizing 24 treatments. Seeds from these cultivars and crosses were evaluated for seed physiological quality based on germination tests, first germination count, accelerated aging, seedlings emergence, and emergence speed index. The lignin content in the soybean seed coat was evaluated. The effects on general and specific combining ability and reciprocal effects were analyzed. There were significant additive and non-additive effects of the genes on the seed quality traits and pronounced effects on the reciprocal traits, which suggest the presence of a maternal effect. Lignin content was not correlated with the physiological test results in the studied genotypes.
Resumo: A seleção e utilização de genótipos de soja com sementes de alta qualidade fisiológica é importante para possibilitar maior probabilidade de estabelecimento e sucesso da cultura em campo, e, consequentemente, alcançar altas produtividades. Objetivou-se neste trabalho avaliar o controle genético da qualidade fisiológica de sementes de soja a partir de um dialelo parcial. Seis cultivares de soja, previamente selecionadas, grupo 1 (CD 201, CA 115, MS 8400) e grupo 2 (CD 202, Syn 1263, Syn 1279), foram intercruzadas utilizando-se um esquema de dialelo parcial, gerando 24 tratamentos. Sementes dessas cultivares e destes cruzamentos foram avaliadas quanto à qualidade fisiológica das sementes a partir de testes de germinação, primeira contagem de germinação, envelhecimento acelerado, emergência e índice de velocidade de emergência de plântulas. Foram avaliados os teores de lignina nos tegumentos das sementes de soja. Foram analisados os efeitos da capacidade geral (CGC) e específica de combinação (CEC) e os efeitos recíprocos. Há efeito significativo dos genes aditivos e não aditivos para os caracteres de qualidade de sementes, e efeito pronunciado de recíprocos, o que sugere a presença do efeito materno. Não há correlação entre o teor de lignina e testes fisiológicos para os genótipos estudados.
In the past, extensive research has been conducted on breeding sweetpotato
Ipomoea batatas
(L.) Lam varieties with improved fresh root yields. However, little attention has been paid to breeding the ...crop for both improved storage root and vine yields for mixed crop-livestock farming systems. Consequently, the objective of this study was to determine gene action and heritability (H) of vine and root yield, and related yield components in sweetpotato. Eight parents selected for their contrasting attributes of root and vine production were hand-crossed in a half-diallel. Thirty-six generated families were evaluated at Rubona, Karama and Ngoma research stations of the Rwanda Agriculture Board. General combining ability (GCA) and specific combining ability (SCA) mean squares were significant for fresh root yield (FRY), root dry matter content (RDMC), dry root yield (DRY), root-to-vine ratio, harvest index (HI) and vine dry matter content. GCA/SCA ratios were much greater than 0.5 for all the root parameters DRY, RDMC and FRY, with 0.75, 0.81 and 0.88, respectively, suggesting that additive gene action was more important than non-additive gene action. H estimates were above 0.5 for all tested parameters, with FRY, HI and RDMC having high estimates of 0.80, 0.81 and 0.92, in that order. Promising families were K5132/61 × Wagabolige, 2005-179 × RW11-1860, 4-160 × 2005-179, K5132/61 × RW11-1860, RW11-2910 × 2005-179, Ukerewe × SPK004 and Ukerewe × 4-160. Progenies derived from the selected families are recommended for further field testing in advanced selection stages at multiple sites for future release.
Twenty one F1 crosses resulting from half diallel mating of seven diverse local landraces of brinjal were studied to know the magnitude of heterosis. The results revealed that, among the 21 crosses, ...BBSR-08-2 × Selection from BBSR-145- 1, BBSR-08-2 × BBSR-10-25 and BBSR-08-2 × BBSR-10-26 exhibited significantly positive heterosis for vegetative growth, fruit yield and fruit yield attributing traits over mid parent, better parent and standard check. The combining ability analysis revealed that, the parents viz. BBSR-08-2, BBSR-10-26 and BBSR-195-3 were good general combiners for plant height, primary branches plant-1, fruit length, fruit girth, average fruit weight, number of fruits plants-1, incidence of bacterial wilt (%) at 90 DAT and fruit yield plant-1. The estimate of sca effect indicated that F1 crosses viz. BBSR-08-2 × BBSR-10-25, BBSR-08-2 × BBSR-10-26, BBSR-08-2 × Selection from BBSR-145-1 and BBSR-10-26 × BBSR-195- 3 were most promising for vegetative traits, fruit yield attributes, reaction to incidence of bacterial wilt at 90 DAT and fruit yield plant-1. Analysis of gene action revealed prevalence of both additive and non additive gene action for yield and its contributing traits. Thus, it may be concluded that, crosses involving parents viz. BBSR-08-2, BBSR-10-26 and BBSR-195-3 exhibited higher heterosis for fruit yield and tolerance to bacterial wilt.
The objective of this study was to determine general combining ability (GCA), specific combining ability (SCA), gene action and heritability of weevil (
Cylass
spp.) resistance, dry matter content ...(DMC), yield and yield-related components of newly developed sweetpotato clones. Six weevil resistant and six susceptible parents were crossed using a 6 × 6 factorial mating design. The resultant 36 families were evaluated at three locations using a 3 × 12 lattice design with two replications for weevil resistance and yield and related traits in western Tanzania. The GCA effect for females was significant except for percentage marketable root number (PMRN) and percentage marketable root yield (PMRY). Significant GCA effect of males were detected for all traits except PMRY. The SCA effect of families was significant for all traits. With a general predicted ratio (GPR) > 0.5, additive gene action controlled more the expression of total root number (TRN), root yield (RY), DMC, percentage infested root number (PIRN), percentage infested root yield and weevil damage score (WDS), whereas non-additive gene action controlled more the expression of PMRN and PMRY with a < 0.5 GPR. The narrow sense heritability for TRN, RY, DMC, PIRN and WDS were 0.24, 0.56, 0.84, 0.62 and 0.62, while the broad sense heritability for these traits were 0.58, 0.72, 0.93, 0.78 and 0.77, in that order. Four female parents and four male parents were identified as the best general combiners and 13 families recorded the best performance for the evaluated traits. The high heritability for most of the traits studded and presence of both additive and non-additive gene action for the traits suggests that genetic gain can be realized through hybridization and clonal selection in breeding programs. The selected parents and families are useful genetic resources for the development of sweetpotato genotypes resistant to weevils and enhanced root yield, yield components and DMC.
The present study was undertaken to analyze diallel data using GGE biplot model to gather information about genetic interrelationships among parents and identification of heterotic combinations for ...yield and yield components in bread wheat varieties. For this purpose, 8 bread wheat genotypes tested across in half-diallel crosses design, GGE biplot technique was used. Parents included the genotypes of Kouhdasht, Karim, Ehsan, Mehregan, N-92-9, Line 17, N80-19 and Atrak. The hybrids obtained from the one-way cross (28 hybrids) in agricultural years of 2016-17 were evaluated as randomized complete block design in two replications on the research farm of Gonbad Kavous University. The evaluated traits included the grain yield, weight of spike grains, number of grains in spike and number of spikes. Additive main effects and genotype × environment interaction (GGE) were employed in the evaluation of genotypes; analyses showed significant (P< 0.01) G × E, (genotype × environment interaction) with respect to plant seed yield. GGE biplot analysis showed that Karim was as the best general combiners for grain yield, number grain per spike and grain weight per spike, whereas Ehsan had the highest GCA effects for number of spikes. Ehsan and Karim had higher specific combining ability than other genotypes. The studied genotypes for this trait were divided into two heterotic groups where the first group included the genotypes of Kouhdasht, N-92-9, N80-19 and Atrak and the second group contained the genotypes of Line 17, Mehregan and Karim. Mehregan line had a weak combining ability with all testers and N-92-9 had also more power than others. Based on the biplot, the Karim genotype with high general adaptation was introduced as the ideal genotype in terms of grain yield, spike number, grain number per spike and grain weight, so the Karim genotype can be adapted to obtain high yield hybrids.
Mexico está enfrentando un déficit en la producción de maíz (Zea mays L.) a pesar de producir 27 millones de toneladas anualmente. Los objetivos de esta investigación fueron estimar y cuantificar la ...acción génica involucrada en cruzas de maíz; y determinar la aptitud combinatoria general, la aptitud combinatoria específica y los componentes genéticos para seleccionar híbridos experimentales con alto rendimiento de grano en el sur de Sonora. Los híbridos se evaluaron en un diseño experimental de bloques completos al azar con tres repeticiones durante el ciclo primavera-verano de 2020-2021. El análisis genético se realizó usando el diseño Carolina del Norte II. Los resultados indicaron que las hembras CML-264 y CML-500; y los machos CML-500 y CML-542 obtuvieron los mayores promedios en todas las variables estudiadas. Sin embargo, las líneas hembras CML-494, CML-545 y CML-264, y los machos CML-550 y CML 542 presentaron mayor efecto de aptitud combinatoria general. Los híbridos CML-264xCML-550, CML-264xCML-555 y CML-494xCML-550 destacaron por ser más tardíos en floración y de porte medio, presentando un mayor rendimiento, peso de mil granos, peso hectolítrico e índice de flotación, asi como también mayores efectos de aptitud combinatoria específica positivos. El híbrido CML-545xCML-542 destacó en precocidad, obteniendo rendimientos aceptables en promedios intermedios. En los componentes genéticos, las varianzas de hembras, dominancia, genética aditiva y heredabilidad influyeron más en todas las variables estudiadas.
Mexico is facing a maize (Zea mays L.) production deficit despite producing 27 million tons annually. The objectives of this research were to estimate and quantify the genetic action involved in maize crosses; and to determine the general and specific combining ability as well as the genetic components to select experimental hybrids with high grain yield in southern Sonora. The hybrids were evaluated in a randomized complete block experimental design with three replicates during the 2020/2021 spring-summer cycle. The genetic analysis was performed using the North Carolina Design II mating design. The results indicated that the female inbreds CML-264 and CML-500; and the males CML-500 and CML-542 obtained the highest average values for all the variables under study. However, the female lines CML-494, CML-545 and CML-264, and the males CML-550 and CML 542 presented a greater general combining ability effect. In particular, the hybrids CML-264xCML-550, CML-264xCML-555, and CML-494xCML-550 were late to flowering and medium-sized, recording higher yield, weight of thousand grains, hectoliter weight and flotation index as well as the highest positive specific combining ability effects. The hybrid CML-545xCML-542 showed early flowering, obtaining acceptable yields in intermediate average values. Regarding genetic components, the variances of females, dominance, additive genetic and heritability had a greater influence on all the variables studied.
The present investigation was undertaken to study the combining ability using 10 lines and 3 testers crossed in Line × Tester mating design. Resulting 30 F1’s were evaluated along with their parents ...in a replicated trial using randomized block design during Kharif season 2016-17 at Norman E. Borlaug Crop Research Centre Pantnagar, Uttarakhand, India. Genotypes were evaluated for grain yield per plant and its contributing characters. Among the lines UPR3912-21-2-1 and tester NDR359 exhibited a high general combining ability (GCA) for most of the characters under the study. The per se performance and specific combining ability (SCA) effects were in agreement with each other for seven hybrids namely Pant Sugandh Dhan17×NDR359, PD26×NDR359, PR113×NDR359, PD26×NDR359, PD26×PD24, Pant Sugandh Dhan17×PD24, PR113×PD24 for days to 50% flowering, the number of tillers, dwarfness, the number of panicles, panicle length, grain length and 1000 grain weight respectively. Cross PD26×NDR359 exhibited high SCA for number of panicles and both the parents were good general combiner for this character.
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