Promising Crosses Research Articles

Towards Streamlining the Choice of Crossing Combinations in Plant Breeding by Integrating Model-Based Recommendations and Plant Breeder’s Preferences

Selecting crossing combinations crucial for successfully developing new improved crop varieties and genomic data from DNA markers have become invaluable for guiding plant breeders in evaluating and choosing promising crosses between potential parents. However, navigating the vast array of thousands of possible parental combinations, even with extensive genomic information, can be challenging, even for experienced breeders with deep knowledge of their crop’s gene pool. This case study aimed to evaluate the effectiveness of a recommender system to support plant breeders in this complex decision-making process. It took a retrospective approach, analyzing selection decisions made by an experienced breeder across several thousand potential crossing combinations over six years. The results indicated that a recommender system could significantly reduce the time and effort needed to identify promising crosses aligned with the breeder’s preferences. However, active feedback from the breeder to the recommender system appeared to be essential for achieving a satisfactory prediction. Integrating model-based recommendations and plant breeder’s preferences in a recommender system featuring such a reciprocal fine-tuning scheme, where the breeder actively provides feedback to the machine in the style of hybrid human–artificial intelligence, represents one step towards streamlining the choice of crossing combinations in plant breeding programs.

ESTIMATION OF HETEROSIS AND COMBINING ABILITY TOWARD MORPHOLOGICAL, YIELD AND QUALITY TRAITS IN TEN SWEET SORGHUM PARENTAL GENOTYPES BY LINE × TESTER ANALYSIS

This study was done to estimate general combining ability (GCA), specific combining ability (SCA) and heterosis regarding better for ten sweet sorghum parental genotypes. Seven lines and three testers were crossed in line ×tester mating fashion on randomized complete block design (RCBD) with three replications at Giza Agriculture Research Station during 2020, 2021 and, 2022 summer seasons. The results showed, significant differences among mean square of parental genotypes and their crosses for all studied traits, suggested present of additive and non-additive genetic variance. In addition, significant mean squares of parents vs. crosses, indicated significant average of heterosis. Besides, the highest values of mean performance were parental genotypes, Brands, Sugar drib, MN1054, MN4080, MN5509 and MN4423, and crosses Brands X MN1054, Ramada X MN4080, Ramada X MN5509, Ramada X MN4423, Sugar drib X MN1054, Sugar drib X MN4080 and Sugar drib X MN1383. Additionally, the best parental genotype that had good GCA effects was MN4423 for most studied traits which may be used in breeding programs for developing high yield varieties. While, the excellent crosses based on SCA effects values were Brands X MN5509, Ramada X MN2756, Ramada X MN1054 and Sugar drib X MN1383. Finally, Heterosis values varied from cross to cross and from trait to trait, which considered promising crosses in breeding programs.

Comparison of residual heterosis in F2 and F3 segregating generations of Indian Mustard [Brassica juncea (L.) Czern & Coss.] crosses

Abstract The present investigation was undertaken to study the residual heterosis in F2 and F3 populations of Indian mustard [Brassica juncea (L.) Czern & Coss.]. The study material included eight parents and the 28 crosses of Indian mustard in two generations, namely F2 and F3. The experiment was conducted over two years at Uttar Banga Krishi Viswavidyalaya, Cooch Behar, West Bengal, during Rabi season 2020-21 and 2021-22. Out of the 28 crosses, three crosses namely, Npj-194 × DRMR-15-16, Npj-194 × RW- 85-59 (Sarma) and Npj-194 × SKJM-05 were found to show significantly positive residual standard heterosis over the standard variety (SKJM-05) for both the characters siliquae per plant and seed yield per plant. This provides us evidence that by improving siliquae per plant, the character seed yield per plant can be improved. The promising cross populations which have shown significant standard heterosis for seed yield in F2 and F3, can be utilized for the development of hybrid varieties, which would be very much beneficial to the marginal farmers of our country as they would be able to use the F2 and F3 seeds of the hybrid varieties without any compromise with seed yield. Keywords: Residual relative heterosis, Residual heterobeltiosis, Residual standard heterosis, Indian Mustard, Segregating generations

Analysis of Component of Genetic Variance, Combining Ability, Gene Action and Heterotic Response in Rice (Oryza sativa. L)

Rice (Oryza sativa L.) is an important staple crop, particularly in Asia, where it feeds more than half the world's population. The analysis of variance (ANOVA) for nine traits in a rice breeding experiment with seven lines, three testers, 24 F1 hybrids, and two checks indicated significant variations between treatments, showing significant genetic diversity. General combining ability (GCA) effects revealed that line MTU 1010 and tester NDR 2026 had favorable GCA effects on grain yield per plant, but NDR 2064 and Barani Deep had negative effects. Three crosses, showed considerable favorable benefits on grain yield due to specific combining ability (SCA). Heterosis analysis identified promising crosses, including Gopal Bhag × Prakhar and NDR-2064 × NDR-2026, that demonstrated considerable positive heterosis above the parent and standard varieties Shushk Samrat and Ashwani. These findings emphasize the possibility of specific crosses to improve grain production in rice breeding efforts.

Leveraging Genomics to Identify Promising Crosses for Superior Wheat Lines

Leveraging Genomics to Identify Promising Crosses for Superior Wheat Lines

Genetic analysis of popping quality traits and development of superior quality popcorn hybrids for a sustainable popcorn breeding program in India.

Popcorn is the most popular specialty maize and it makes a significant contribution to the Indian and global economies. Despite perfect exploration of heterosis in field corn, progress in popcorn breeding remains constrained due to its narrow genetic base, leading to a significant dependence on imports. In this study, 15 landrace- and population-derived inbreds from temperate and tropical germplasm were crossed with five testers, which are the parents of superior popcorn hybrids, in a line × tester mating design. Significant variation was observed in popping quality and agronomic traits among crosses evaluated across three locations representing diverse maize-based agro-climatic zones in India. Additive genetic variance governed the traits related to popping quality, whereas dominance variance was responsible for the agronomic traits. In addition to significant heterosis specific to certain traits, we identified promising crosses that exhibited superior performance in both popping quality and grain yield (GY). The genotype + genotype × environment (GGE) biplot methodology identified PMI-PC-104 and PMI-PC-101 as the best discriminating testers for popping quality traits and Dpcl-15-90 for GY. Lines PMI-PC-205, PMI-PC-207, and PMI-PC-209 were the best general combiners for popping quality traits and GY. The heterotic groups identified based on GGE-biplots and the magnitude, direction and stability of combining ability effects would serve in the development of competitive popcorn hybrids for a sustainable popcorn market. Using the additive nature of popping quality traits and the dominant nature of GY, recurrent intrapopulation selection can be employed to derive desirable popping quality inbreds with high GY for genetic enhancement. Desirable popping quality alleles from novel germplasm can thus be combined with high-yielding domestic elite inbreds to establish a sustainable popcorn breeding program. © 2024 Society of Chemical Industry.

Assessment of Bitter Gourd Hybrids for Charantin and Other Vital Qualitative Traits

A field experiment was conducted in the Vegetable Experimental Field, College of Horticulture in Venkataramannagudem, Andhra Pradesh, during the summer and kharif seasons of 2022 in order to identify parents and cross combinations which have performed best for major quality attributes. To generate 21 F1 crosses, seven parents were maintained in a parental block (Summer 2022) and crossed in a half diallel mating pattern. For quality parameters like TSS, vitamin-C and iron the crosses viz., Preethi× Special Boldar, Kashi Mayuri× IC -68314, IC-68314 × Special Boldar were identified as promising ones. Charantin is important quality attribute, which was reported to be anti-diabetic in nature. Kashi Mayuri × IC-68314, IC-433630 × IC-68314 and IC-68314 × Special Boldar among the hybrids while IC-68314, IC-469512 and IC-433630 among the parents were found to be best performers for the charantin content in fruits. The identified promising crosses were further evaluated under multilocational trails and various seasons to know the potentiality before commercial release.

Diversidade genética em progênies de meios-irmãos de couve: Uma abordagem multivariada

ABSTRACT Kale is one of the most widely cultivated leafy vegetables in Brazil, but its breeding genetic is still limited. Therefore, it is crucial to develop research that explores the genetic diversity of the available germplasms, aiming to establish promising crosses in the studied populations. The present study aimed to evaluate the genetic divergence between half-sibling progenies of kale, obtained through recurrent selection, using multivariate methods to select the most promising progenies for forming a recombinant population. The plants obtained from the seeds of 25 pre-selected half-sibling progenies and three commercial cultivars were evaluated as treatment groups. These seeds were produced in 2018 by subjecting the clones of the progenies to recombination, followed by the selection of appropriate seeds from plants with superior agronomic performance. In the present study, plants in each plot were evaluated for twelve quantitative and fifteen qualitative traits. Genetic divergence was studied based on canonical variables to obtain quantitative data. The UPGMA method was applied to the quantitative, qualitative, and combined data, and Mahalanobis genetic distance was adopted. The first three canonical variables explained 73.75% of the total cumulative variation compared to the commercial cultivars and 55.29% when considering the half-sibling progenies exclusively. The half-sibling progenies P1, P2, P3, P4, P5, P9, P11, P15, P16, P18, P20, P22, P23, P24, and P25 were the most divergent and should, therefore, be prioritized when composing the recombinant population for the third cycle of recurrent selection because, in addition to genetic variation, these progenies also present characteristics of interest to the kale genetic breeding program. The commercial cultivars exhibited the most divergent genotypes and should, therefore, be included in the next recombination cycle.

Breeding design in wheat by combining the QTL information in a GWAS panel with a general genetic map and computer simulation

A large amount of genome-wide association study (GWAS) panels together with quantitative-trait locus (QTL) information associated with breeding-targeted traits have been described in wheat (Triticum aestivum L.). However, the application of mapping results from a GWAS panel to conventional wheat breeding remains a challenge. In this study, we first report a general genetic map which was constructed from 44 published linkage maps. It permits the estimation of genetic distances between any two genetic loci with physical map positions, thereby unifying the linkage relationships between QTL, genes, and genomic markers from multiple genetic populations. Second, we describe QTL mapping in a wheat GWAS panel of 688 accessions, identifying 77 QTL associated with 12 yield and grain-quality traits. Because these QTL have known physical map positions, they could be mapped onto the general map. Finally, we present a design approach to wheat breeding by using known QTL information and computer simulation. Potential crosses between parents in the GWAS panel may be evaluated by the relative frequency of the target genotype, trait correlations in simulated progeny populations, and genetic gain of selected progenies. It is possible to simultaneously improve yield and grain quality by suitable parental selection, progeny population size, and progeny selection scheme. Applying the design approach will allow identifying the most promising crosses and selection schemes in advance of the field experiment, increasing predictability and efficiency in wheat breeding.

Estimation of Magnitude of Heterosis for Grain Yield and Related Traits in Sesame (Sesamum indicum L.)

Sesame (Sesamum indicum L.) is an important oilseed crop which is native to India and cultivated in around 2.3 million ha across its several states. India stands way below in terms of productivity compared to several other countries across the globe. Being an often-cross pollinated crop, heterosis even in a marginal magnitude could be exploited in sesame in varietal development. Hence, the present study was performed with the objective of estimating the extent of relative heterosis, heterobeltiosis and standard heterosis in eight cross combinations for important yield attributing traits in sesame in order to select promising cross combinations for utilization in heterosis breeding and/or selection of superior segregants in segregating generations. Eight cross combinations derived out of crossing high yielding parents viz., TMV (Sv) 7 and VRI (Sv) 2 as female and E8, DSS 9, DS 5 and Prachi as male in L × T fashion were utilized for the analysis considering TMV (Sv) 7 as the Standard parent. The analysis showed significant differences between the genotypes for all the characters studied. The hybrids showed Relative/ Mid parental heterosis ranging from 2.02 to 26.05 per cent; heterobeltiosis from -4.55 to 15.85 per cent and standard heterosis from -11.27 to 15.85 per cent for grain yield /ha. Mid Parental Heterosis (RH) was found to be positive and significant for the characters no. of branches/plant, no. of capsules / plant, grain yield (kg/ha) in all the hybrid combinations except VRI (Sv) 2 / Prachi. Based on heterobeltiosis, the hybrids TMV (Sv) 7 / E 8, TMV (Sv) 7 / DSS 9, TMV (Sv) 7 / DS 5, VRI (Sv) 2 / DS 5 could be selected since they showed significant heterobeltiosis for important yield contributing characters viz., no. of branches / plant, no. of capsules /plant and grain yield. With respect to the Standard heterosis for grain yield and contributing characters like no. of branches/plant, no. of capsules/plant and grain yield/ha the hybrids viz., TMV (Sv) 7 / E 8, TMV (Sv) 7 / DS 5 and TMV (Sv) 7 / DSS 9 showed positive and significant heterosis. Considering all the three types of heterosis, the hybrids TMV (Sv) 7 / E 8, TMV (Sv) 7 / DS 5 and TMV (Sv) 7 / DSS 9 may be selected for yield enhancement in Sesame.

Heterosis and Inbreeding Depression for Yield and Quality Traits in Tomato (Lycopersicon esculentum Mill.)

Ten parental lines of tomato (Lycopersicon esculantum Mill.) were crossed in 10 x 10 diallel mating plan barring reciprocals. The 45 F1 hybrids along with their parents and one standard check (Pusa Ruby) were evaluated in a randomized block design with three replications. This study relevant that heterosis over the better parent, mid-parent, standard check and inbreeding depression was observed for all the traits under study. Highly significant heterosis was observed for Days to first flowering (-18.35, -14.42 and -3.30%), Days to 50% fruiting (-13.41, -12.30 and -6.71%), Fruit diameter (41.20, 46.07 and 35.57%), fruits length (49.20, 63.23 and 5.98%), Average fruit weight (59.26, 66.89 and 26.72%), Number of fruits per plant (135.19, 159.63 and 80.67%), Number of fruits per cluster (54.55, 54.55 and 80.02%) and total yield per plant (123.71, 146.41 and 99.13%) over the better, mid and standard parents, respectively along with considerable inbreeding depression. The most promising cross EC-165700 × EC-164563 appeared intensely noteworthy positive heterosis over way better parent for total yield per plant. These Heterotic hybrids found superior over better parents and one standard check have the potential to be exploited commercially.

Genetic analyses of stay green for tolerance to water stress and nitrogen deficiency in Algerian Saharan maize populations

Delayed senescence could contribute to maintain yield under water stress and low nitrogen stress. Landraces from arid areas can provide favorable alleles for stay green under stress. The objectives of this study were to estimate varietal and heterosis effects of Algerian Saharan populations and their crosses for stay-green under water stress and no-nitrogen fertilization and to identify the most promising populations as sources of stay-green under stress. Six Algerian maize populations were evaluated in a diallel under water stress (300 mm irrigation) versus control (600 mm) and no-nitrogen fertilization versus 120 kg/ha N fertilization. Both varietal and specific heterosis were involved in delayed senescence under stress. Breeding programs could capitalize additive components by using the populations IZM or IGS with favorable varietal effects for delayed senescence under nitrogen stress, or dominance effects by using the population AOR with favorable heterotic effects for plant color under water and nitrogen stresses. Based on specific heterosis, under water stress conditions with no-nitrogen supply, the most promising cross was AOR × IZM for delayed senescence, while IZM × BAH (with no-nitrogen supply), and SHH × BAH (with nitrogen fertilizer), will allow a longer maintenance of the plant coloration. We suggest reciprocal recurrent selection with these populations for developing drought-tolerant and low nitrogen hybrids to improve stay-green.

Heterosis Studies for Root-Yield-Attributing Characters and Total Alkaloid Content over Different Environments in Withania somnifera L.

Ashwagandha is an important, medicinal, less exploited crop and most of its cultivated varieties are local cultivars. Information related to ashwagandha’s genetic diversity is very limited. Hybrid vigor exploitation may be useful in breaking its yield barrier at a commercial scale. A total of 45 F1 crosses were produced during Kharif 2017-18 by using a line x tester matting design, which included three testers along with 15 lines. A total of 65 genotypes were grown in an RBD design, with three replications in three different environments during Kharif 2018-19, and observations were recorded for 11 different yield-attributing traits that were responsible for the estimation of the magnitude of the heterosis. An analysis of variance showed that a valuable amount of diversity existed in the breeding material. Based on the study, three promising crosses viz., UWS-305 × UWS-10, UWS-305 × RVA-100, and UWS-301 × RVA-100 were identified as superior heterotic materials for the root yield at harvest, whereas for the total alkaloid content, three excellent hybrids viz., UWS-309 × RVA-100, UWS-305 × RVA-100, and UWS-314 × RVA-100 were reported. Out of the above crosses, the cross-combination of UWS-305 × RVA-100 showed a significantly positive and useful heterosis on a pooled basis. Hence, the above crosses may be gainfully utilized in breeding programs for ashwagandha.

Combining ability analysis for grain yield and quality characters in pearl millet [Cenchrus americanus (L.) Morrone

The objective of the present study is to estimate the combining ability effects among parents and their crosses in pearl millet, to identify promising cross combinations for grain yield and its component traits. In combining ability analysis, the extent of sca variance was higher than gca variance for all of the characters demonstrating the predominance of non-additive gene action except for panicle length and 1000-grain weight. The estimates of general combining ability suggested that parents, RIB 17 S/109, RIB 16300, RIB 37-40 S/17, RIB 13-16 S/17, ICMA 96666 and ICMA 94111 were good general combiners for yield and its contributing characters. The best hybrid, ICMA 94111 x RIB 16296 involved low x low performing parents which exhibited high positive and significant SCA effect for grain yield and most of the yield contributing and quality traits like protein, iron and zinc. These good combiner lines may be exploited to develop iron and zinc rich hybrids along with grain yield to alleviate malnutrition in people of the country. Keywords: Pearl millet, combining ability, gene action, male sterile line, tester.

Heterosis and Estimation of General and Specific Combining Ability as Base for Selected Superior Recombination of the Some Crossed Cotton Genotypes

The objective of this study was to determine the general and specific combining abilities and heterosis of some cotton genotypes for yield, its components and fiber traits using line x tester mating design. Nine parents (six line and three testers) were crossed in a line x tester mating design in 2020 season. Nine parents along with their eighteen F1 crosses were studied in a randomized complete block design (RCBD) with three replications during 2021 at Sakha. Agricultural. Research. Station. Kafr El-Sheikh, Governorate, Egypt. Based on line x tester analysis, the variance due to genotypes, parents, crosses and parent vs. cross exhibited significant differences (P. 0.01) for most yield, yield components and fiber traits. The variance due to GCA of lines x testers and SCA of line x tester interactions were highly significant for most studied traits, indicating the importance of both additive and non-additive gene actions in controlling these traits. The estimates of GCA and SCA effects revealed that the parent and some crosses were having desirable and significantly GCA and SCA effects, respectively. High mean performances and significantly GCA effects values were observed of line Giza 92, Giza 75 and tester Giza 97 for most studied traits, hence, these parents can be used as for generation superior cotton hybrids. The best values of mean performances, SCA effects and heterosis were found in the combinations Giza 94 x Giza 92, Giza 97 x Suvin for most yield and yield components and the cross Giza 97 x (Giza 75 x Sea) for yield and fiber traits. These crosses are considered as the promising crosses to be used in breeding programs for produce hybrid cotton and improvement for these traits in Egypt.

"HY-LINE INTERNATIONAL" COMPANY BREEDING ACHIEVEMENTS

"HY-LINE INTERNATIONAL" COMPANY BREEDING ACHIEVEMENTS

Combining ability study on yield and its contributing traits in maize (Zea mays L)

Experimental material consisted of 25 lines, 2 testers and their 50 crosses along with standard checks viz., Palam Sankar Makka-2 and PSCL 4640 were evaluated using Randomized Block Design with two replication during Kharif 2020. Genotype mean square was significant for days to 50% tasseling, days to 50% silking, days to 75% brown husk, ear height (cm), plant height (cm), ear length (cm), ear circumference (cm), kernel rows/cob, kernels/row, 1000-kernel weight (g), shelling (%) and grain yield (q/ha) which indicated the presence of sufficient genetic variability in the material studied. Also the ratio of GCA variance to SCA variance was less than unity for all traits indicated preponderance of non-additive gene action. Among lines, KI-3 exhibited higher grain yield followed by KI-7 and CML 140. These lines also exhibited highest significant GCA effect for grain yield and were identified as promising parents. KI-7 × LM 13, CML 140 × LM 13, CML 139 × LM 13, CML 162 × LM 13 and KI-3 × LM 14 exhibited maximum SCA effect for most of traits. These promising cross combinations need to be evaluated in multi-location trials over the years to assess their suitability in different agro-climatic zones of the State.

​Comparative Study of Crossability Behavior in Intra-specific and Inter-specific Crosses of Vigna radiata and Vigna mungo

Background: The basic plant material consisted of 9 mungbean and 5 urdbean genotypes. 42 different crosses were made comprising 13 Vigna radiata x V. radiata, 4 V. radiata x V. mungo and 25 V. radiata x V. mungo crosses. Varying degree of success has been achieved in obtaining intraspecific and interspecific crosses having desired variability for yield and yield contributing traits along with MYMV resistance. Methods: The present investigation was done at Agricultural Research Farm, Banaras Hindu University, Varanasi, during Kharif, 2019 and Summer, 2020. 42 intra-specific and inter-specific cross combinations were initially examined for their crossability. Out of these, six promising crosses with higher crossability percent were further analyzed for hybrid pollen fertility, hybrid lethality and, evaluation of F1 and parents for different yield traits . Result: Crossability per cent found highest in intraspecific cross HUM 2 x IPM 02-3 (41.86%) in mungbean while, in urdbean cross NDU 1 x R3/12 (41.38%). In interspecific crosses, the maximum crossability per cent was found in SKAU M 365 x R3/28 (34.92%). Two mungbean genotypes (HUM 2 and HUM 26) and two urdbean genotypes (R3/12 and R3/28) can be further utilized for genetic improvement through inter-specific hybridization as there cross combinations are better performing on the basis of yield attributes along with MYMV resistance.

Estimates of genotypic and phenotypic variance, heritability, and genetic advance of horticultural traits in developed crosses of cowpea (Vigna unguiculata [L.] Walp).

Cowpea, in addition to being a food and feed crop, plays a key role in sustainable farming. The present study’s goal is to develop new high-yielding cowpea varieties. A Field experiment was carried out across 3 summer seasons and the breeding program included 28 distinct cowpea varieties, out of which five potential parents were selected for this investigation. Local cultivars, i.e., Cream 7 ‘Cr7’, Dokki 331 ‘D331’, Commercial 1 ‘Com1’, and introduced cultivars, i.e., Colossus ‘Col’ and Asian Introduction ‘AI’ were utilized to produce six crosses in two generations apart; F1 and F2: Col x AI, Col x Com1, Cr7 x AI, Cr7 x Com1, D331 x AI, and D331 x Com1. ‘AI’ and ‘Com1’ were superior in pod length, pod diameter, number of seeds/pod and seeds weight/pod, whereas ‘Col’, ‘Cr7’ and ‘D331’ were superior in seeds yield/plant, number of pods/plant and the least number of aborted ovules/pod. The genotypes/crosses showed greater genotypic variance (GV) than phenotypic variance (PV) for number of pods/plant, pod length, number of seeds/pod, number of aborted ovules/pod, fresh pod weight, seeds weight/pod, and seeds yield/plant. All studied variables showed high heritability (H%) in genotypes/crosses, despite the exception of seeds weight/pod, which ranged from 29.14 in ‘D331’ to 83.7 in F2 of Col x Com1. F2 plants and their parents’ genotypes showed greater H%. Cr7 x AI developed the most H%, 99.04% for number of pods/plant. D331 x Com1 and Cr7 x AI exhibited moderate H% for fresh pod weight in F1, but all other crosses had high H%. F1 and F2 crosses yielded moderate to high GCV and PCV for number of seeds/pod. Variations in parental genotypes and crossings reflect genetic diversity and the possibility of selection. Crossing with ‘AI,’ and ‘Com1’ genotypes enhanced the performance of the other varieties, ‘Col’, ‘D331’ and ‘Cr7’. Cr7 x Com1 and D331 x AI were selected as the most promising crosses for cowpea breeding programs.

Estimation of General and Specific Combining Ability Effects for Quality Protein Maize Inbred Lines

Background: Maize (Zea mays L.) plays a critical role in meeting high food demand. It is globally one of the most widely adapted and cultivated crops. Hybrid development from fixed inbred lines is one of the strategies for the improvement of maize production. The national average maize yield in Ethiopia is low and thus, selection of promising germplasm and knowledge of combining ability are prerequisites to developing high yielding maize varieties. Forty-two Quality Protein Maize (QPM) crosses (21 inbred lines each crossed with two testers) along with three popular standard hybrids were evaluated in two replications using alpha lattice during the 2017 cropping season at Ambo, Arsi-Negele, and Kulumsa. The objectives of this study were to identify lines with high GCA and estimate the SCA of crosses for grain yield, and other agronomic and morphological characters.
 Results: Significant difference among crosses was observed for 19 traits at Ambo, 14 traits at Arsi-Negele, and 19 traits at Kulumsa in the hybrid trial. Regarding the GCA effect, L8 had a significant difference to the positive side with the highest magnitude of GCA effect at three locations (3.40, 2.03, and 1.88 GCA effect values at Arsi-Negele, Ambo, and Kulumsa, respectively) which is followed by L7 for GY. All crosses did not show a significant SCA effect for GY in both directions at Ambo and Arsi-Negele but at Kulumsa, five crosses: L2xT1(1.89), L13xT2(1.88), L7xT1(1.86), L4xT2(1.49) and L19xT1(1.41) showed significant difference. In the combined analysis for six traits, Additive gene action was more important which was manifested by a higher sum square contribution of DS (79.6) EPP (79.3%), EL (80.0%), KPR (80.1%), ED (78.5%) and TSW (79.1%).
 Conclusion: Based on mean grain yield, and combining ability, L8xT2, L7xT1, L8xT1, L19xT1, L6xT2, and L18xT1 are promising crosses that could be forwarded for further use in maize breeding programs for further works.