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The current breeding effort aims to develop new wheat genotypes with higher genetic potential, thereby contributing to food security. Ten wheat genotypes were crossed in a half-diallel mating design. The F1 progeny from the 45 crosses, along with their ten parents, were evaluated in a randomized block design to estimate combining ability and the nature of gene action. Analysis of variance for combining ability revealed significant mean squares for both general and specific combining abilities across all studied traits. This indicates the importance of both additive and non-additive gene effects in the inheritance of these traits. The GCA/SCA ratio suggested the predominance of non-additive genetic action for all studied traits. Only five parents (HD3086, UP 2748, WH 1105, UP 2565, and HD 2967) exhibited good general combining ability for yield and associated traits. However, but none of them were found good combiners for all traits. Twenty-one crosses exhibited significant specific combining ability for yield and associated traits. The crosses UP 2748 x HD 3059, UP2565 x HD3086, WH 1105 x UP 2526, WH 1105 x WH 1021, and HD 2967 x WH 1021 were identified as good specific combiners for higher grain yield and associated traits. Utilizing these crosses in breeding programs that exploit heterosis can lead to the creation of new wheat genotypes with a broader genetic base. This approach, which involves crossing high-performing parents for some traits with low-performing parents for others, has the potential to produce offspring with superior characteristics in the next generation due to interactions between dominant genes. [ABSTRACT FROM AUTHOR]

The present study was undertaken during October, 2020-January, 2021 at Maize Research Centre, Professor Jayashankar Telangana State Agricultural University, Rajendranagar, Hyderabad, Telangana state, India to identify potential inbred lines and hybrids with early maturity and high yield through combining ability analysis and heterosis. Six lines and four testers were crossed in L×T design to obtain 24 crosses. Evaluation of these crosses and their parents for combining ability revealed significant differences due to lines, testers and their crosses indicating the existence of wider variability among the material used in the study. Maize line MGC 434 (91 days), two testers GP-170 and PFSR-56 (91 days), and one hybrid MGC-445×PFSR-132 (83 days) were identified as early duration genotypes. Four lines MGC-444 (-3.13), MGC-440 (-2.71), MGC-439 (-1.96) and MGC-445 (-0.46) with significant negative GCA effects were identified as best general combiners for early maturity. Eight hybrids, MGC-439×BML-14 (-4.99), MGC-445×PFSR-56 (-4.65), MGC-461×PFSR-56 (-3.65), MGC-445×PFSR-132 (-3.60), MGC-434×BML-14 (-2.32), MGC-439×GP-170 (-2.10), MGC-440×PFSR-56 (-2.07) and MGC-440×GP-170 (-1.01) with significant negative SCA effects were considered as best cross combinations with early maturity. The inbred parents and cross combinations with early maturity identified in the study can be utilized for development of hybrids suitable to drought prone environments. [ABSTRACT FROM AUTHOR]

Copyright of Ecosistemas y Recursos Agropecuarios is the property of Universidad Juarez Autonoma de Tabasco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Bottle gourd [Lagenaria siceraria (Molina) Standl.] is cultivated for multiple utilities, including as a leafy vegetable, for fresh and dried fruits and seeds. It is an under-researched and -utilized crop, and modern varieties are yet to be developed and deployed in sub-Saharan Africa (SSA). There is a dire need for pre-breeding and breeding of bottle gourds for commercialization in SSA. Therefore, this study aimed to determine the combining ability and heterosis among selected genotypes of bottle gourd for fruit yield and related traits under drought-stressed and non-stressed conditions to select the best parents and hybrids. Eight preliminarily selected and contrasting parents with drought tolerance were crossed using a half-diallel mating design. The 8 parents and 28 crosses were evaluated under non-stressed (NS) and drought-stressed (DS) conditions across two growing seasons (2020/21 and 2021/22) using a 6 × 6 alpha lattice design with three replicates. Data were collected on fruit yield and related traits and subjected to analysis of variance, combining ability and heterosis analyses. Significant (p < 0.05) specific combining ability (SCA) and general combining ability (GCA) effects were computed for fruit yield per plant (FYPP). The SCA × environment and GCA × environment interaction effects were highly significant (p < 0.001) for FYPP and SYPP. The results suggest that genetic effects were affected by the test environment. Parental genotypes BG-58 and GC recorded positive and significant GCA effects for FYPP under the DS condition, whereas GC recorded positive and significant GCA effects for FYPP under the NS condition. The two genotypes are ideal breeding parents for population development to select genotypes with high fruit and seed yields. Crosses BG-27 × BG-79, BG-79 × BG-52, BG-79 × BG-70, BG-80 × BG-70, BG-80 × GC, and BG-70 × GC recorded high and positive SCA effects for FYPP and SYPP under DS condition. Crosses BG-81 × BG-52, BG-81 × GC, BG-27 × BG-79, BG-27 × GC, BG-79 × GC, BG-80 × BG-70, BG-81 × BG-58, BG-27 × BG-80, BG-27 × BG-58, BG-79 × BG-52, BG-52 × BG-58, BG-80 × BG-58, and BG-58 × BG-70 recorded high and positive SCA effects for FYPP and SYPP under NS condition. Crosses BG-80 × BG-58, BG-27 × BG-79, BG-79 × BG-52, BG-27 × BG-52, and BG-52 × BG-80 showed high and positive mid- and better-parent heterosis under DS condition for FYPP and SYPP. Crosses BG-27 × GC, BG-79 × GC, BG-27 × BG-58, and BG-27 × BG-79 showed high and positive mid- and better parent heterosis under NS condition for FYPP and SYPP. The newly selected families are recommended for multi-environment evaluation forrelease and commercialization in South Africa or similar agroecologies. [ABSTRACT FROM AUTHOR]

Abstract To generate high-yielding cultivars with favorable fiber quality traits, cotton breeders can use information about combining ability and gene activity within a population to locate elite parents and potential F1 crosses. To this end, in the current study, twelve cotton parents (eight genotypes as female parents and four testers) and their F1 crosses obtained utilizing the linex tester mating design were evaluated for their general and specialized combining abilities (GCA and SCA, respectively) of yield traits. The findings showed that for all the investigated variables, variances owing to genotypes, parents, crosses, and parent vs cross showed extremely significant (P ≤ 0.01) differences. Additionally, throughout the course of two growing seasons, the mean squares for genotypes (parents and crosses) showed strong significance for all the variables under study. The greatest and most desired means for all the examined qualities were in the parent G.94, Pima S6, and tester G.86. The best crossings for the qualities examined were G.86 (G.89 × G.86), G.93 × Suvin, and G.86 × Suvin. The parents' Suvin, G89x G86 and TNB were shown to have the most desired general combining ability effects for seed cotton yield/plant, lint yield/plant, boll weight, number of bolls/plants, and lint index, while Suvin, G.96 and pima S6 were preferred for favored lint percentage. For seed cotton yield, lint percentage, boll weight, and number of bolls per plant per year, the cross-G.86 x (G.89 × G.86) displayed highly significant specific combining ability impacts. The crosses G.86 × Suvin, Kar x TNB, G.93 × Suvin, and G.93 × TNB for all the studied traits for each year and their combined were found to have highly significant positive heterotic effects relative to better parent, and they could be used in future cotton breeding programs for improving the studied traits.

Copyright of Egyptian Journal of Agronomy is the property of Egyptian National Agricultural Library (ENAL) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Selfing and crossing methods were used to develop the cytoplasmic male sterility (CMS) lines from 2 elite F1 hybrids of CMS hot chilies. The pungency of the CMS lines was improved by backcrossing with the B cultivar. The first and second backcrossed progenies of the CMS lines showed significantly higher capsaicin contents than the F1 hybrids. One good female line K16 × BBC2 (K16), was selected and backcrossed with 3 good maintainer cultivars, C5, C9 and C0. Some incomplete male sterility of pollens was demonstrated in the F1 hybrids and the 1st backcrossed progenies while the partial sterility disappeared by the stage of the second and third generations of backcrossing. When K16 and P32 were crossed with restorers, fruit yields and yield components of certain F1 hybrids, parental lines and commercial varieties were significantly different. Heterosis of yield and yield components of the F1 hybrid chilies was significant. When K16 was used as a female parent, positive and significant heterosis of the F1 hybrids was the same as P32. Moreover, significant GCA of the restorer lines, C7, C8 and C9, was observed in some horticultural characteristics. Furthermore, significant differences of the specific combining ability of some characteristics were observed in a few F1 hybrids. [ABSTRACT FROM AUTHOR]

With the application of hybrid wheat, lodging is becoming one of the major factors limiting high yield in its production. However, few studies have focused on combining ability and heterosis analysis of stem-related traits. In this study, 24 crosses were made according to NCII genetic design, using the three (photo-sensitive male sterile lines)×eight (restorer lines) incomplete diallel crosses. The length of basal second internode (LBSI) and breaking strength of basal second internode (BSBSI) as well as other stem-related traits were used to perform the principal component analysis (PCA), combining ability and heterosis analysis. The PCA results showed that the variables could be classified into two main factors, which were named as the positive factor (factor 1) and the negative factor (factor 2), and accounted for 52.3 and 33.2%, respectively, of the total variance in different variables, combined with the analysis for index weight indicated that the factor 1-related traits play positive roles in lodging resistance formation of hybrids. Combining ability variance analysis indicated that its genetic performance was mainly dominated by additive gene effects, and the hybrid combinations with higher lodging resistance can be selected by using of 14GF6085 (R1), 14GF6343-2 (R4), 14GF6937 (R6), 14GF7433-1 (R7), and BS1086 (M3), which are with the features with lower general combining ability (GCA) effects of factor 2-related traits whereas higher GCA effects of factor 1-related traits. The heterosis analysis showed that the wide range of heterosis varied with the traits and combinations, and GCA or specific combining ability (SCA) effects of factor 1-related traits except wall thickness of basal second internode (WTBSI) were positively and closely related to the heterosis of lodging resistance. Generally, the correlation coefficients of heterosis to GCA effects of sterile lines (GCAm) of factor 1-related traits are significantly higher than that to GCA of restorer lines (GCAr) and SCA, combined with the higher GCAm variance values of factor 1-related traits compared to GCAr, the GCAm of factor 1-related traits should be particularly considered when breeding hybrid combinations. The heritability analysis showed that the narrow-sense heritability of the diameter of basal second internode (DBSI) and the center of gravity height (TCGH) were obviously lower (

Increasing seed yield, fatty acids, and essential oil content are the main objectives in breeding coriander. However, in order to achieve this, there is a need to understand the nature of gene action and quantify the heterosis and inbreeding depression. Towards this, six genetically diverse parents, their 15 F1 one-way hybrids, and 15 F2 populations were evaluated under different water treatments. The genetic effects of general (GCA) and specific combining ability (SCA) and their interactions with water treatment were significant for five traits. Water deficit stress decreased all traits in both F1 and F2 generations except for the essential oil content, which was significantly increased due to water deficit stress. Under water deficit stress, a non-additive gene action was predominant in the F1 generation, while an additive gene action was predominant in the F2 generation for all the traits except seed yield under severe water deficit stress. There was a positive high heterosis for the traits examined in some hybrids. Furthermore, in the F2 generation, even after inbreeding depression, some promising populations displayed appropriate mean performance. The results show that the parents used for crossing had a rich, diverse gene pool for the traits studied. Therefore, selection between the individuals of relevant F2 populations could be used to develop high yielding hybrids or superior lines. [ABSTRACT FROM AUTHOR]

Powdery mildew is one of the most important diseases of cucurbits in the world and Iran. The disease is found in cucumbers, melons, cantaloupes, squash, and watermelons in both farm and greenhouse conditions and causes great damage. Cultivating resistant cultivars or chemical control with fungicides can be used to control this disease. In this study, 28 different genotypes of hullless seed pumpkin were studied and compared for powdery mildew resistance in potted conditions in a greenhouse. To achieve this, the genotypes in the greenhouse were sprayed with powdery mildew spores, and when signs of powdery mildew appeared through infection on the plants, the severity of the disease was determined by image processing using a program written in MATLAB software. The mean comparison showed that the lowest level of infection was related to lines 11 and 23 and hybrids of 7x16, 2x16, and 2x23. The highest negative general combining ability was related to line 11 and the highest negative specific combining ability was related to hybrids 7x14, 2x16, 2x23, and 11x14. The highest negative heterosis compared to the high parent was related to 11x14, 2x23, and 2x16 hybrids. Due to the significant values obtained for specific combining ability and significant heterosis in hybrids, the role of dominance variance in controlling this trait is prominent, and hybrid production is recommended to improve resistance to powdery mildew. [ABSTRACT FROM AUTHOR]

To generate high-yielding cultivars with favorable fiber quality traits, cotton breeders can use information about combining ability and gene activity within a population to locate elite parents and potential F1 crosses. To this end, in the current study, twelve cotton parents (eight genotypes as female parents and four testers) and their F1 crosses obtained utilizing the linex tester mating design were evaluated for their general and specialized combining abilities (GCA and SCA, respectively) of yield traits. The findings showed that for all the investigated variables, variances owing to genotypes, parents, crosses, and parent vs cross showed extremely significant (P ≤ 0.01) differences. Additionally, throughout the course of two growing seasons, the mean squares for genotypes (parents and crosses) showed strong significance for all the variables under study. The greatest and most desired means for all the examined qualities were in the parent G.94, Pima S6, and tester G.86. The best crossings for the qualities examined were G.86 (G.89 × G.86), G.93 × Suvin, and G.86 × Suvin. The parents' Suvin, G89x G86 and TNB were shown to have the most desired general combining ability effects for seed cotton yield/plant, lint yield/plant, boll weight, number of bolls/plants, and lint index, while Suvin, G.96 and pima S6 were preferred for favored lint percentage. For seed cotton yield, lint percentage, boll weight, and number of bolls per plant per year, the cross-G.86 x (G.89 × G.86) displayed highly significant specific combining ability impacts. The crosses G.86 × Suvin, Kar x TNB, G.93 × Suvin, and G.93 × TNB for all the studied traits for each year and their combined were found to have highly significant positive heterotic effects relative to better parent, and they could be used in future cotton breeding programs for improving the studied traits. [ABSTRACT FROM AUTHOR]

Combining ability and heterosis were used to assess the performance of the genotypes of the parent and their hybrids. This research aimed to evaluate the effects of heterosis and combining ability on the diallel crosses of melon (Cucumis melo L.) for yield and quality-related traits. Ten genotypes of melons were grown and crossed in full diallel to produce F1 hybrids. This research was conducted in 2021 by planting 100 melon genotypes in a randomized block design with three replications. Analysis of variance showed significant (P 0.01) differences among the melon genotypes for fruit diameter, fruit weight, fruit flesh thickness, and fruit total soluble solids. Combining ability analysis showed that mean squares due to general combining ability (GCA) were significant for fruit diameter, fruit weight, flesh thickness, and total soluble solids. In addition, the specific combining ability (SCA) was significant for the characters of fruit diameter, fruit weight, flesh thickness, and fruit total soluble solids. The parental genotypes 2, 3, and 10 showed the highest GCA effect for the yield characters. Therefore, this genotype can be used to produce high-yield hybrid cultivars. The research results show that all characters' GCA: SCA ratio was less than 0.50, meaning most of the traits were controlled by non additive gene action and verifying that the breeding material could be efficiently used to produce hybrid cultivars based on heterotic effects. [ABSTRACT FROM AUTHOR]

Combining ability analysis discriminates the parents and crosses, provides information about the breeding method to be adopted for genetic improvement of a specific character. Thirty hybrids obtained by mating two females with fifteen males in L × T fashion were evaluated in RBD along with parents to estimate the combining ability of parents and crosses for seed yield and yield contributing traits. The parents and hybrids significantly differed amongst themselves for different characters, viz., days to maturity, 100 seeds weight, capsules per plant, branches per plant, seed yield, seed volume weight and oil content. Among the males, GMU-590, GMU-2273, GMU-2830 and GMU-589 and the females, AKS CMS-3B had good gca effects for seed yield and some other yield contributing traits. However, GMU7573 and GMU-2830 were found best general combiners for the trait oil content. All these selected parents may be utilised in a different breeding programme for genetic enhancement of the trait involved. The hybrids AKS CMS-2A × GMU-1731 and AKS CMS-3A × GMU-7448 were identified as good combinations for seed volume weight and capsules per plant. Whereas the hybrids AKS CMS-3A × GMU-2273 and AKS CMS-2A × GMU-6891 were effective for seed filling percentage and seed yield per plant. Three promising hybrids viz., AKS CMS-3A × GMU-7448, AKS CMS-3A × GMU-2273 and AKS CMS-2A × GMU-6891 were designated as promising hybrids as they had good per se performance and significant sca effects for seed yield per plant and most of its contributing characters which can be utilized for heterosis breeding and release of new hybrids at commercial level after thorough multilocation testing. Further, the hybrids AKS CMS-3A × GMU-7448, AKS CMS-3A × GMU-590 and AKS CMS-3A × AKS-589 involving one or both good general combining parents with non-significant sca effects for many studied characters which may be utilized to isolate desirable segregants in progressive generations for identification and release of new varieties by hybridizing the ‘B’ lines of concerned CMS line with similar males again. [ABSTRACT FROM AUTHOR]

The exploitation of heterosis is possible only when the parents involved in the crosses show high specific combining ability in the hybrids. Fifty hybrids generated from ten lines (land races) and five testers along with parents were evaluated for eight quantitative traits to elucidate the nature of gene action present in the inheritance of important quantitative traits. Preponderance of non additive gene action was observed for all the characters studied. RAJAMUDI and MOHINI SAMBA among the lines and ASD 16 and CO 47 among the testers were found to be good general combiners as they could contribute alleles with positive effect for improving the important quantitative traits. The crosses RAJAMUDI × ASD 16, RAJAMUDI × CO 47 and MOHINI SAMBA × ASD 16 performed better than the check varieties CO 51 and ASD 16 for most of the traits and showed significance for standard heterosis and these three crosses can be further forwarded to recombination breeding.

Combining ability and heterosis analysis were performed in ten lines, five testers and their fifty hybrid combinations of maize using line x tester analysis. Combining ability analysis among the sixteen traits revealed significant line x tester interaction for most of the traits studied. Variance due to sca was found to be more than gca for all the traits studied which indicated the preponderance of non-additive gene action. Among the parents, the lines viz., N67, N10-65-3, N10-153-1-2 and the tester UMI 1210 exhibited higher per se along with positive gca effects and found to be good general combiners among the parents. Standard heterosis was calculated by comparing TNAU maize hybrid CO 6 as the standard check. Considering the per se, sca and standard heterosis, single cross hybrid N10-65-3 x E.No.8 was identified as the best hybrid for grain yield and other major yield contributing traits followed by the hybrid N44 x UMI 1221.

The productivity of chili pepper (Capsicum annuum L.) can be increased by the use of hybrid cultivars. Promising hybrid cultivars can be obtained by maximizing the combining ability value between two parents. The objective of this study was to estimate the general combining ability and specific combining ability (SCA) of the yield components and capsaicin content of chili plants obtained via diallel crossing. This study was conducted at the Leuwikopo Experimental Field, Department of Agronomy and Horticulture, Bogor Agriculture University. The experimental design was a single-factor randomized complete block design with three replications. On the basis of the results, the C5 × F074 hybrid was identified as the recommended hybrid for improving productivity potential. The Bara × F9160291 cross showed positive heterosis and the highest mean performance and SCA effects for capsaicin content. The C5 × F6074 hybrid showed high mean performance and the highest SCA effect for fruit weight per plant. The results of this study can be exploited further in chili breeding for the development of hybrids with high capsaicin content and productivity or hybridization programs. [ABSTRACT FROM AUTHOR]

Abstract: The genus Capsicum is cultivated in various parts of the world, with C. annuum showing high diversity and potential for ornamental purposes and genetic improvement. The aim of this work was to evaluate the combining ability and heterosis of seedling and plant traits in accessions of ornamental pepper and their hybrids. Seven accessions of C. annuum were handcrossed and twelve quantitative plant traits were evaluated. The data were subjected to analysis of variance, the Scott-Knott test and diallel analysis using Griffing’s method I (fixed model). Heterosis and its components were also determined. Non-additive effects were found for seedling height, cotyledonous leaf length and width; stem diameter and chlorophyll b content. All other traits showed predominance of additive effects. Heterosis effects were found for some hybrids and UFPB134 x UFPB137, UFPB134 x UFPB390, UFPB134 x UFPB004 and UFPB099 x UFPB004 showed seedlings that are more vigorous.

Two field experiments were carried out during the 2014 and 2015 seasons to evaluate certain genotypes of Egyptian cotton under well irrigated and water stress conditions. The cross combination Giza 69 x Australy recorded the best values for better parent heterosis for all physiological measurements and earliness index under well irrigated and deficit conditions. Of the female parents, Giza 86 was found to be a good general combiner for most yield characters under both normal and stress conditions, followed by Giza 94. Data illustrated that Giza 45 was the best general combiner for most fiber quality traits under both conditions. The cross combinations Giza 86 x Dandra and Giza 69 x Pima S6 showed significant positive SCA values for seed cotton and lint yield/plant under well irrigated and water deficit conditions. However, the combinations Giza 77 x PimaS6 and Giza 94 x 10229 recorded significant positive SCA effects for seed cotton yield/plant under stress. Whilst, the cross Giza 68 x 10229 recorded significant desirable SCA effects for most fiber quality properties. In this context, the estimates significant positive general and specific combining ability effects indicated that the epistasis and/or dominance effects for F1 hybrid in cotton could be important to a certain extent. [ABSTRACT FROM AUTHOR]

ADOPTION of quality protein maize in Egyptian maize breeding programs would maximize the nutritional value of maize products. However, the assessment of adaptability of exotic quality protein maize germplasms is an important step before incorporating them in breeding programs. The current studies consisted of two experiments including a preliminary evaluation of some exotic quality protein maize inbreds and combine eight adapted elite inbreds into a halfdiallel cross. The current study revealed that CML158 exhibited the highest significant general combining ability effect with an average grain yield/plant of 53.0g. While CML492 contained the highest percentages of both protein (14.5%) and tryptophan (1.02%) with the highest values of general combining ability effects. Based on specific combining ability, the best parental combination for grain yield/plant was CML182×CML184, which yielded 239g and exceeded the average grain yield/plant of all hybrids (201.5g). It seems that CML143 possesses favorable alleles for increasing the percentage of protein (CML143×CML557) and tryptophan (CML158×CML491 and CML143×CML182) because it was a common parent in the best parental combinations for both traits. Mid-parent heterosis % varied from trait to trait; however, the highest amount of heterosis was detected in grain yield/plant due to its polygenic state. In conclusion, superior hybrids in yield and quality were detected. These hybrids need further evaluations across years and locations to assess stability. These hybrids can be considered as a cheap and sustainable source of high protein and tryptophan content for human consumption, which might play a magnificent role in food security in Egypt. [ABSTRACT FROM AUTHOR]

Heterosis and combining ability are two important considerations in the utilization of heterosis, which can be used to generate excellent hybrid resource candidates and is very important in conventional hybrid breeding. In this study, the combining ability, heritability, and heterosis of eight major agronomic traits were analyzed in 10 tomato parents and 45 crosses between them. As well as TY-301, a recognized and official excellent variety that is currently selling well on the market was used as a control to conduct a control heterosis analysis, with the goal of selecting ideal parents with high combining ability and new hybrids with commodity value, high yield, early maturity, and high quality. The results showed that both additive and nonadditive genetic effects are involved in the expression of the traits and that the additive genetic effect is dominant in trait inheritance. Although general combining ability (GCA) and specific combining ability (SCA) were not correlated, and the strength of heterosis depends on SCA, the sum of the parental GCA values (GCAsum) did predict heterosis for some traits with higher predictive accuracy than did SCA. Compared with heterosis, GCAsum can better predict hybrid performance. Finally, the parent 17,969 was the breeding material with the best comprehensive trait performance, especially in yield. We screened a high-yielding candidate combination 17,927 × 17,969 and a precocious and good taste candidate combination 17,666 × 17,927. This information may play an important role in the selection of superior parents and hybrid combinations based on combining ability and heterosis analysis.

The aim of this study was to estimate the combined ability and analyze the genetic variance components of synthetic maize populations using diallel crossing with a mixed model approach. Twelve synthetic varieties were crossed following the complete diallel scheme without reciprocals, resulting in 66 intervarietal hybrids, which were evaluated along with the parental populations and four commercial cultivars in three different environments. An experiment was performed on 82 genotypes using a randomized complete block design with three repetitions. The evaluated traits were ear height (EH), plant height (PH) and grain yield (GY). Griffing's Model II, Method 2 and Gardner and Eberhart's Model II were combined for diallel analysis, along with the UPGMA method based on predicted breeding values (BLUP). The non-additive genetic effects were the most important for plant architecture and grain yield within each synthetic population, as based on the GCA and SCA. Clusters 1 and 2 separated by UPGMA can be included in breeding programs to obtain hybrids, and cluster 3 can be used to obtain genotypes with lower plant architectures and higher productivity in intrapopulation breeding programs. [ABSTRACT FROM AUTHOR]

An attempt was made to develop small fruited ash gourd [Benincasa hispida (Thunb) Cogn] hybrids by crossing 10 genetically diverse ash gourd genotypes in a diallel mating system. The 45 F1 hybrids along with their parents were evaluated for assessing their heterosis and combining ability for 11 important economic traits. The parent P2 (Elevenchery local) was the best general combiner for fruit yield and fruits/plant. The specific combining ability component of variance (∂2s) was higher than general combining ability component of variance (∂2g) for the all the 11 characters studied which indicated the predominance of non-additive gene action in the improvement of these characters. The hybrids, viz. P2 × P7 (Elevenchery local × Chengamanad) which exhibited the highest heterosis over top parent (79.95 %) and highly significant sca effects for fruit yield, fruit length, flesh thickness, average fruit weight and days to first fruit harvest followed by P3 × P4 (Malappuram × IC 392313) which recorded the highest heterosis over better parent (166.38%) and highly significant sca effects for fruit yield, fruits/plant, flesh thickness and fruit length were found promising. Both the hybrids were small fruited with average fruit weight (2.04 kg) and (1.65 kg) respectively.

Intra species hybridizations have been extensively used to produce varieties with superior characteristics for use in aquatic animals. In this study, maternal effects, general and specific combining ability, heterosis and inbreeding depression of growth-related traits, including weight gain, changes in length, weight, body length and width, as well as losses in the form of a complete diallel cross in pure and cross breed results is analyzed in three strains of Green and Albino Tiger Barb. The results showed that the highest rates of maternal effects on traits was related to species such as Albino and mother line had the best performance compared to other species. General combining ability for Green Barb in the three traits (body weight, body length and width) and two species of Albino trait body weight gain and changes was higher during the performance. Comparison of the ability of a particular compound represents an albino genetic gene pool as well as line paternal mother, in combination with other two species. Investigation about the amount of heterosis showed that its value in four traits of length, weight, length and width, were negative, but the rate of weight gain and mortality were positive. These two traits indicated high genetic distance between parents. The inbreeding depression, the highest rate of body length and the lowest among growth traits were related to weight gain.

This study was carried out to select waxy corn inbreds with good general combining ability through a diallel analysis of 10 half diallel crosses among five inbreds developed from Korean maize landraces. Total of 21 agronomic and palatability traits were investigated over two locations in 2016. There was a significant hybrid by location interaction found in plant height, ear height, number of tillers/plant, per ear weight, ear tip filling, ear commercial value and sweetness when four additional check cultivars were included in the analyses. A significant general combining ability by location interaction was found in ear height, number of tillers/plant, per ear weight, ear length and sweetness while ear width, ear commercial value and sweetness were significant for specific combining ability by location interaction. Sweetness was found significant for both interactions. The first and fourth inbred lines had the most number of traits with good estimate of general combining ability. The first inbred is expected to improve days to tasseling, anthesis silking interval, ear width, ear circumference and sweetness while decreasing husk cover in a hybrid combination. The fourth inbred line would improve days to tasseling, days to silking, plant height, ear height, per ear weight and ear length but ears would be a bit tougher than the average. A total of 19 traits had higher variance of general combining ability than that of specific combining ability. Husk cover was 12.1 times higher. Plant height and number of tillers/plant had higher variance of specific combining ability. Keywords : Diallel analysis, Waxy corn hybrid, General combining ability. [ABSTRACT FROM AUTHOR]

The purpose of this research was to evaluate the combining ability of six local Iranian and one imported cantaloupe cultivar. Heritability of traits was estimated using a half-diallel mating design. Seven parents and their crosses were evaluated in 2013 and 2014. The greatest general combining ability ( GCA) for yield and fruit number was for 'Rish-baba' (0.53 kg/plant and 0.3, respectively). The cultivar 'Ananasi' had the highest GCA for fruit weight and soluble solids content ( SSC) (0.088 kg and 1.4, respectively). 'Ananasi' presented the highest GCA values for fruit firmness, chlorophyll a and b and carotenoid content, as well as the highest total chlorophyll content. The cross Garmak × Rish-baba showed the highest specific combining ability ( SCA) for yield with heterosis value of 99%. High heritability estimates for SSC (0.52), flesh thickness (0.61) and concentration of chlorophyll a (0.7) were obtained. Although there were significant SCAs for yield, the parents are suggested to be improved prior to hybrid development. The parent 'Ananasi' appears to be a suitable donor in breeding programmes. [ABSTRACT FROM AUTHOR]

Ten parental lines diverse in fruit biochemical traits were crossed in a half-diallel mating design to produce 45 F 1 hybrids. A total of 55 genotypes were evaluated for fruit biochemical traits and dry fruit yield to determine the mode of gene action, extent of heterosis, and combining abilities that facilitate in designing the best strategy for breeding peppers for industrial use. Different proportions of hybrids with positive to negative heterosis were obtained for different traits. The IHR3849 × IHR3448 F 1 hybrid showed high standard heterosis for dry fruit yield per plant (35.42% ** ) and total capsaicinoid content (13.75% ** ). Estimates of combining ability effects showed that IHR500, IHR2451, and IHR4516 were the most suitable parents for developing hybrids for dry products processing industries. Both additive and dominance components were found significant in controlling the biochemical traits; the predominance of the additive effect was observed in capsaicinoids and dominance was observed for carotenoids. The results suggest that biparental mating, recurrent selection, single seed descent method, and heterosis breeding are the best approaches for breeding peppers for high carotenoids. Reciprocal recurrent selection at early stages is the best approach for breeding for a high dry pepper yield with high capsaicinoids. [ABSTRACT FROM AUTHOR]

Twenty eight non-reciprocal F1 hybrids derived from eight diverse cucumber genotypes were evaluated in randomized block design with three replications to study the heterosis and combining ability for quality attributing traits in cucumber. The analysis of variance indicated significant variability among all the genotypes for all the traits. The mean square due to gca and sea were highly significant for all the characters indicating the importance of both additive and non-additive genetic components for the characters under study. The parent 'Gy- 14' was the best combiner for flesh to seed cavity ratio and (β-carotene and Swarna Sheetal was best combiner for ascorbic acid and dry matter content. The cross combination EC-27075 x Summer Kheera had highest sca for total soluble solids whereas Pant Kheera-1 x Japanese Long Green had highest sca for ascorbic acid. The cross combinations, Pant Kheera-1 x Summer Kheera and Swarna Sheetal x EC-27075 had highest sca for mineral content. The cross combination JLG x NCH-1 exhibited maximum heterosis for flesh to seed cavity ratio over better parent (16.67%) and standard check, NS-404 (11.11%) whereas JLG x Summer Kheera exhibited maximum heterosis for total soluble solids over better parent (31.06%) and standard check, NS-404 (34.39%). The study on gene effect of different characters indicated the predominance of non-additive gene effects for most of the characters. Therefore, the improvement for these characters can be achieved through hybrid development. [ABSTRACT FROM AUTHOR]

Rice (Oryza sativa L.) breeding seeking to combine high productivity and cold tolerance for the temperate Latin America region is an important challenge. We estimated some useful parameters which can be used to investigate the genetic control of agronomic characters in crosses combining cold tolerance and productivity. A partial diallel design was used in crosses between six tropical indica rice cold susceptible genotypes (group 1) and seven japonica or indica/japonica cold tolerant rice genotypes (group 2). Parents and crosses were evaluated for agronomic characters under field conditions in two different experiments in 2005. The results showed significant mid-parent heterosis for all characters (plant height, tiller number, days to 50% flowering, panicle length, grains per panicle, sterility, and one-hundred grain weight). The predominant direction of dominance effects was negative for days to 50% flowering, and positive for all the other characters. General combining ability (GCA) and specific combining ability (SCA) were significant for all characters, although the GCA effects of the two groups were more important than the SCA effects.

High temperatures can significantly reduce tomato (Solanum lycopersicumL) yield. A 5 × 5 diallel cross was used under high temperatures in a greenhouse to estimate combining ability and understand the genetic basis of tomato genotypes under heat stress. Additive gene action was predominant in governing most heat-tolerant morphological traits; yield was governed by nonadditive gene action. A cross involving high × high general combining ability (gca) or high × low gca had better specific combining ability (sca) effects. The genetic components and proportions studies showed heat tolerance was governed by nonadditive gene action and is a dominant trait. The parental variance (Vr) and parent–offspring covariance (Wr) relationship (Wr–Vr) indicated that heat tolerance traits were governed by overdominance. Significant correlation occurred between yield and yield-attributing traits. Heterosis was high for yield and most yield-attributing traits. Heterosis breeding involving crosses with high gca parents ‘CLN1621E × Nagcarlan’ and ‘BL1176 × Nagcarlan’ could be used to improve tomato for yield during heat stress. Selection for heat tolerance traits should be in early generations followed by selection for yield. [ABSTRACT FROM PUBLISHER]

Yields of maize ( Zea mays L.) are remarkably low in sub-Saharan Africa and yet farmers have limited access to improved varieties. The objective of this study was to determine combining ability and heterosis of 18 elite maize inbred lines in environments prone to northern corn leaf blight (NCLB) disease in the mid-altitude tropics. Nine elite inbred lines were crossed as females with nine male lines using the North Carolina Design II mating scheme and 81 hybrids were generated. The hybrids, parents and three standard check varieties were evaluated using an alpha lattice design with two replications across seven environments in the mid-altitude sub-humid agro-ecologies in Ethiopia. The new top ranking hybrids displayed up to 250 % high-parent heterosis and mid-parent heterosis for grain yield and up to −25 % high-parent mid-parent heterosis for NCLB reaction. The specific combining ability (SCA) by site interaction was not significant, suggesting that the top yielding hybrids were relatively stable across environments. Inbred lines such as CML 395, 30H83-7-1, ILO'OE-1-9, 124-b (113), CML202, CML312, and Gibe-1-91 resulted in significant SCA effects for grain yield were selected as promising parents. Lines CML395 and ILO'OE-1-9 had negative and significant general combining ability (GCA) effects for NCLB reaction, implying the resistance of the inbred lines for NCLB. The most performing experimental hybrids such as CML-312 × CML395, CML197 × CML395, CML443 × DE-78-Z-126-3 had high SCA effects and produced mean grain yields of >8 t ha. The new hybrids may be used directly for production or as testers in hybrid development with resistance to NCLB. [ABSTRACT FROM AUTHOR]

Bread wheat genotypes with slow rusting stem rust resistance were crossed in a half-diallel mating design to identify superior parents for stem rust resistance combined with high grain yield (GY) and related traits. Significant mid-parent heterosis for area under disease progress (AUDPC) was observed in crosses 7041-1 × Danda'a and Danda'a × Kubsa. H04-2 × Danda'a showed significant mid-parent heterosis for GY, thousand kernel weight (TKW), number of tillers per plant (TPP) and reduced plant height (PLH), and significant better-parent heterosis for GY. Significant general combining ability (GCA) effects for all characters and specific combining ability (SCA) effects for most of the traits indicated the contribution of additive and non-additive genes in the expression of these traits, respectively. GCA and SCA ratios ( $$\sigma_{\text{gca}}^{ 2} /\sigma_{\text{sca}}^{2}$$ ) were less than unity for GY, TKW and PLH, suggesting preponderance of non-additive gene action at F1 for these traits. Additive gene action was predominant in the inheritance of AUDPC, kernels per spike, TPP and days to maturity. H04-2, Digelu and Danda'a showed strong GCA effects for most of the characters investigated. Crosses 231545-1 × H04-2, 7041-1 × H04-2, Digelu × Kubsa and Danda'a × Kubsa were good combinations for AUDPC. H04-2 × Danda'a, Digelu × Kubsa and Danda'a × Kubsa were good combinations for GY and TKW. Overall, H04-2 and Danda'a were good general combiners, and crosses involved these lines performed well for most of the traits. Hence, these lines may be used in breeding programs to develop stem rust resistant and high yielding cultivars. [ABSTRACT FROM AUTHOR]

Elevated level of late maturity α-amylase activity (LMAA) can result in low falling number scores, reduced grain quality, and downgrade of wheat ( Triticum aestivum L.) class. A mating population was developed by crossing parents with different levels of LMAA. The F and F hybrids and their parents were evaluated for LMAA, and data were analyzed using the R software package 'qgtools' integrated with an additive-dominance genetic model and a mixed linear model approach. Simulated results showed high testing powers for additive and additive × environment variances, and comparatively low powers for dominance and dominance × environment variances. All variance components and their proportions to the phenotypic variance for the parents and hybrids were significant except for the dominance × environment variance. The estimated narrow-sense heritability and broad-sense heritability for LMAA were 14 and 54 %, respectively. High significant negative additive effects for parents suggest that spring wheat cultivars 'Lancer' and 'Chester' can serve as good general combiners, and that 'Kinsman' and 'Seri-82' had negative specific combining ability in some hybrids despite of their own significant positive additive effects, suggesting they can be used as parents to reduce LMAA levels. Seri-82 showed very good general combining ability effect when used as a male parent, indicating the importance of reciprocal effects. High significant negative dominance effects and high-parent heterosis for hybrids demonstrated that the specific hybrid combinations; Chester × Kinsman, 'Lerma52' × Lancer, Lerma52 × 'LoSprout' and 'Janz' × Seri-82 could be generated to produce cultivars with significantly reduced LMAA level. [ABSTRACT FROM AUTHOR]

Diallel crosses have been widely used for analysis of general combining ability (GCA), specific combining ability (SCA) and heterosis. In the present research, 12 lines were selected from 60 inbred rice bred by International Rice Research Institute with extremely-high or -low yielding records according to the previous three consecutive seasons of yield trial experiments, to construct a half diallel cross. The genetic distances (GDs) revealed by molecular markers for the 12 lines ranged from 0.2288 to 0.7169, averaging at 0.5882; clustering analysis showed the 12 lines were divided into four groups maintaining the original cluster structure of the 60 lines. The positive loci (PLs) including effective-increasing loci (ILs) and effective-decreasing loci (DLs) were screened. The results showed that hybrids derived from those parents with higher GCA effects had better performance for traits of yield and yield components. The SCA effects were strongly correlated to F performance as well as heterosis; the GDs based on ILs were significantly positive correlated to SCA effects and heterosis for yield and yield components while the GDs based on DLs showed the significant negative correlations. Based on this research, a new conception, i.e. general sum of combining ability (GSCA) was conceived, which is defined as the sum of GCAs for two parents of a hybrid. The GSCA and SCA showed similar correlations with traits of yield and yield components. The results illustrated that ILs could be used for further study on prediction of heterosis for traits of yield and yield components; and GSCA may be another considerable parameter combined with ILs for breeders in selecting elite hybrid. [ABSTRACT FROM AUTHOR]

Blight diseases are one of the serious causes of low tomato productively in Pakistan. Two susceptible but high yielding lines Riogrande and Roma were crossed with LB2, LB3, LB4 and LB7 following line x tester mating design to generate 8 F1 hybrids. All genotypes were evaluated to find high yielding and disease resistant combiners and their hybrids against check hybrid T-1359. Whole plant assay elucidated LB2, Roma x LB3 and Roma x LB4 tolerant to late blight. The same assay also expounded LB3, LB4, LB2, LB7 and Riogrande x LB2 tolerant to early blight. Non-additive gene action was observed to control each blight type, fruit length, fruit weight and 1000-seed weight except number of fruits per plant and fruit diameter. Female x male interaction affixed highest place to line x tester interaction by 48% for late blight and 84% for early blight. Riogrande, LB2 and LB7 were good general combiner for tolerance to early blight while Roma and LB3 for late blight. The perusal of high mean performance, specific combining ability effects and commercial heterosis simultaneously led to the isolation of two promising hybrids Roma x LB3, Roma x LB4 for late blight and Riogrande x LB2 for early blight. These three hybrids have been submitted in competitive multi-location field trails to adjudge their yield performance and blight response before commercialization. [ABSTRACT FROM AUTHOR]

Investigation was carried out to determine combining ability and heterosis for yield and its component traits in rice. The material consisted of F1 hybrids of 30 crosses developed by crossing 10 lines with three testers. The cross HPR 2639 X HPR 2143 is good specific combination for grain yield/plant, panicle length, spikelets/panicle, grains/panicle, biological yield/plant, days to 50% flowering and plant height. Another hybrid, HPR 2529 X HPR 1156 also shows high heterosis over standard check for grain yield/plant biological yield/plant, grain fertility and plant height. [ABSTRACT FROM AUTHOR]

Studies on tropical popcorn ( Zea mays L. ssp. mays) gene pools are still scarce. The objective of this study was to infer tropical popcorn gene pools by employing molecular and phenotypic information. Forty-eight inbred lines and 140 individuals belonging to the Viçosa and Beija-Flor popcorn populations were genotyped using 90 simple sequence repeat (SSR) and 93 single nucleotide polymorphism (SNP) markers, respectively. Grain yield and expansion volume were analyzed for the inbred lines and the hybrids obtained from intra- and interpopulation diallels. The cluster analysis based on SSR markers grouped 46 inbred lines into two groups according to their origin population. Principal coordinate and population structure analyses based on SSR and SNP markers confirmed the results from the clustering. For grain yield, midparent heterosis was greater in the interpopulation hybrids than in the intrapopulation hybrids. The genetic distance did not correlate with the specific combining ability effects and showed a week to intermediate correlation with hybrid performance and midparent heterosis. Based on the results from clustering, population structure, genetic diversity, heterosis and diallel analyses, Viçosa and Beija-Flor populations belong to distinct gene pools. Furthermore, inferring tropical popcorn gene pools might be more efficient if molecular marker and phenotypic data are combined. [ABSTRACT FROM AUTHOR]

In rabi season 2012, six diversed maize inbred lines were crossed in all possible combinations without reciprocals by using a half diallel mating design to obtain 15 single cross. Inbred parents and their F1 single crosses with a check were evaluated in rabi season 2013 to evaluate the role of general and specific combining ability and heterosis for some quantitative traits. Significant general combining ability variances was observed only for cob height and specific combining ability variances were observed for plant height, cob height, cob length, cob girth, number of kernels per cob, cob weight and hundred grain weight. The GCA/SCA ratio was less than unity for all studied traits except shelling percentage; this means that these traits are pre-dominantly controlled by non-additive gene action. Based on GCA estimates, it could be concluded that the best combiners were ML01, ML05 and ML29 inbred lines for most of the studied traits. This result indicated that these inbred lines could be considered as good combiners for improving these traits. Significant positive SCA effects were found for all studied traits except number of kernels per row and shelling percentage. Based on SCA effects, it could be concluded that the crosses ML01×ML02, ML02×ML05, ML02×ML29 and ML05×ML15 could be exploited by the maize breeders to increase maize yield. Three F1 hybrids such as ML02×ML15, ML02×ML29 and ML05×ML15 proved to be the outstanding hybrids to immediate further steps for commercial cultivation. In a conclusive decision the F1 hybrid, ML02×ML29 was the best combination as evaluated through combining ability and standard heterosis. [ABSTRACT FROM AUTHOR]