Estimates Of Heterosis Research Articles

Estimation of heterosis for kernel yield and its attributing traits in maize (Zea mays L.)

Estimation of heterosis for kernel yield and its attributing traits in maize (Zea mays L.)

Estimation of nonadditive and additive genetic effects on growth traits of Horro cattle.

The estimation of nonadditive genetic effects plays a significant role in the accuracy of estimated breeding values for growth traits. Data for estimation of individual and maternal heterosis of crossbreed cattle in Ethiopia are limited to research institutions and universities. This paper aimed to estimate the crossbreeding effects for growth traits of Holstein Friesian × Horro and Jersey × Horro crossbreds in Ethiopia. The data included pedigree and weight data of animals born between 1980 and 2008. Heritability of growth traits was estimated using restricted maximum likelihood (ASREML). However, the additive genetic, maternal, and heterosis effects for growth traits of crossbred animals were estimated using the crossbreeding effects (CBE3) package by fitting Kinghorn's Model one. The direct and maternal heritability estimates for 1-year weight with the model that included the direct maternal covariance were 0.77 ± 0.12 and 0.26 ± 0.09, respectively. Individual heteroses estimated for Holstein Friesian × Horro and Jersey × Horro were significantly high and positive for 1-year weight (21.6 ± 6.7 and 26.0 ± 3.9kg), preweaning average daily gain (27.4 ± 26 and 28.9 ± 15g), and postweaning average daily gain (68.8 ± 16.6 and 61.8 ± 9.9g), respectively. The maternal additive genetic effect for growth traits was mostly positive; therefore, it may be preferable to use crossbred cows from purebred dams instead of crossbred cows from crossbred dams. The significantly higher heterosis and additive genetic parameters in Holstein Friesian × Horro crossbreds indicated that these crossbreds may be preferable to Jersey × Horro crossbreds in areas occupied by Horro cattle.

Stability Analysis of Quality Protein Maize Hybrids Qualitative and Quantitative Traits under Heat Stress across Different Environments of Prayagraj District in Central India

Maize, also known as corn (Zea mays .L), is one of the world's most important cereal crops. Maize is the only food cereal crop that can be produced throughout the year and requires a moderate environment to thrive. This study claims to determine whether such a statement is accurate and to examine stability in terms of gene action. The study was carried out in three research sites representative different places in CRF, SHUATS, Prayagraj City at an elevation of 98 meters above sea level at 25.87ON latitude and 81.54 OE longitude. and all the locations has sub-tropical climate with extremes of summer and winter. During winter season especially in month of December and January, temperature drops down to as low as 1-20 C, while during summer the temperature reaches up to 450C (NICMEIT 2022). This experiment was undertaken under Randomized Block Design with three replications for assessing their stability. The mean squares due to genotypes, parents, hybrids, and parent vs. hybrids were very significant for all eighteen quantitative and qualitative characters under study, according to the analysis of variance for diallel analysis (model I method II). A stability study was carried out to determine the grain yield of 45 maize hybrids under three environments (E1, E2 and E3), using Eberhart and Russel model. The analysis of variance for combining ability revealed the mean squares due to general combing ability (GCA) and specific combing ability (SCA) were highly significant for all characters studied. Inbred lines P4, P5 and P2 showed significant to highly significant positive GCA effects on grain yield per plant and its attributes, indicating that both parents were good general combiners for this trait. Four hybrids (P5 X P7, P5 X P6, P4 X P8 and P4 X P5) exhibited significant to highly significant SCA effects for grain yield per plant. The estimates of standard heterosis over the best check (HQPM-5) for grain yield per plant revealed five top cross combinations (P5 X P7, P5 X P6, P4 X P8, P5 X P9 and P4 X P5), exhibiting highly significant positive standard heterosis regarding their high and stable performance across environments. The single cross hybrids over all the environments P5 X P6, P5 X P7 and P4 X P5 were found promising for the majority of characters studied, with high mean performance across environments. Based on a regression coefficient close to unity (βi ≈1) and a non-significant deviation from regression (s2di), indicating their adaptability across all environments investigated, best performing hybrids were identified according to three different environments in E1, E2 and E3 were P1 X P6, P2 X P4, P2 X P6, P2 X P8, P3 X P5, P4 X P5, P4 X P7, P4 X P10, P5 X P6, P5 X P7, P6 X P8, P7 X P8, P7 X P9, regression coefficient near to unity (βi ≈1) and non-significant deviation from regression (s2di) there by indicating its adaptability over all environments, thus indicating stable performance in different environments for most of the characters.

Standard Heterosis Estimation for Quality Protein Maize Hybrids Over Best Released and Commercialized Hybrids

Maize plays an indispensable role in meeting high food demand. It is globally one of the most widely adopted and cultivated crops. Hybrid development from fixed inbred lines is one of the tactics to boost maize production. The national average maize yield in Ethiopia is low and thus, selection of promising germplasm, knowledge of combining ability, and heterotic grouping are prerequisites to develop high-yielding maize varieties. Forty-two Quality Protein Maize (QPM) single crosses (21 inbred lines each crossed with two testers) along with three popular standard hybrid checks were evaluated in two replications using alpha lattice design during the 2017 cropping season at Ambo, Arsi-Negele, and Kulumsa. The objective of this study was to estimate standard heterosis for grain yield (GY), and other agronomic and morphological characters. 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. For GY, at Ambo, almost all crosses showed negative heterosis against the best check (AMH853). At Arsi-Negele 14 crosses had positive standard heterosis, from these only three crosses: L8xT1 (50.8%), L8xT2 (46.6%), and L7xT1 (33.9%) showed significant difference against Jibat but at Kulumsa, the difference for standard heterosis was positive but non-significant only by two crosses: (L7xT1 (6.6%) and L19xT1 (4.7%). Based on mean grain yield and standard heterosis, L8xT2, L7xT1, L8xT1, L19xT1, L6xT2, and L18xT1 are promising. The study of the results highlighted that the breeding program was successful in generating superior QPM hybrids. Based on the finding we suggest that it is better to use the parents of theses hybrids as potential source materials in the breeding program through to form different crosses formation.

Genetic analysis in eggplant (Solanum melongena) hybrids for high‐rainfall areas utilizing diverse germplasm with respect to fruit shape and colour

AbstractIn the present study, 20 F1 cross combinations developed through diallel mating design utilizing five diverse parents, namely, Res‐1, Res‐2, Hisar Shyamal, Arka Nidhi, and Arka Keshav, with respect to shape and colour of the fruits were evaluated to derive information on combining ability and heterosis for yield and yield contributing traits in eggplant. Parents Res‐2, Hisar Shyamal, and Arka Nidhi were recognized as good general combiners for most of the horticultural traits. Cross combinations, namely, Res‐2 × Arka Nidhi, Hisar Shyamal × Res‐1, and Arka Nidhi × Hisar Shyamal, recorded high SCA values for fruit yield and related traits. Cross combinations Res‐2 × Arka Nidhi, Arka Nidhi × Hisar Shyamal, Hisar Shyamal × Res‐1, and Res‐2 × Res‐1 were found to be superior based on estimates of heterosis for fruit yield. Heterosis was positively correlated with SCA, the sum of the parental GCA indicating more effective predictions of the performance of various cross combinations. These unique cross combinations, Res‐2 × Res‐1 (medium–long shape and mixed colour), Res‐2 × Arka Nidhi (long and purple), Hisar Shyamal × Res‐1 (round and purple), and Arka Nidhi × Hisar Shyamal (oblong and purple), were found to be superior based on specific combining ability and heterosis for most of the horticultural traits. Therefore, these can be utilized for fixing genes in subsequent generations to increase the chance of recovering desirable transgressive segregants with improved traits for high rainfall areas in eggplant for better economic returns.

Estimation of Heterosis and Combing Ability for some Grain Traits of Rice under Saline Sodic Soil Conditions

Estimation of Heterosis and Combing Ability for some Grain Traits of Rice under Saline Sodic Soil Conditions

Combining ability and heterosis estimates for yield and its components in bread wheat (Triticum aestivum L.) under different sowing dates

Combining ability and heterosis estimates for yield and its components in bread wheat (Triticum aestivum L.) under different sowing dates

Multi-environment Assessment of Combining Ability, Heterosis of Bt Introgressed Lines and Hybrids of Upland Cotton (Gossypium hirsutum L.)

A study was conducted at Dharwad, Raichur and Aurangabad in India during the rainy season of 2018 to investigate the environmental impact on combining ability and heterosis estimates in cotton. Combining ability analysis across locations showed significant effects on the performance of genotypes, GCA, SCA, genotype×environment, GCA×environment and SCA×environment interactions for most of the characters. Combining ability variance revealed the predominance of non-additive gene actions for characters under study. The parents and crosses varied with locations for combining ability and better parent heterosis estimates. Out of 22 parents, ten parents recorded high overall gca and among them, two BGII, six BGI and two non-Bt parents were under study. Similarly, 55 hybrids were exhibited high overall sca and better parent heterosis from the study and most of the crosses were derived from lines crossed with high overall gca (H) with low overall gca (L) or vice versa. This study indicated the requirement of parents with contrasting gca effects to realize a higher frequency of heterotic hybrids. The predominance of H×L type of crosses indicated the presence of non-additive gene action suggesting exploitation of good heterotic hybrids from the study. The frequency of hybrids with high overall sca and heterobeltiosis was more in BG II hemizygous hybrids compared to BG II homozygous condition with H×L type. Similar were the results with BGI hemizygous hybrids.

The Combining Ability for Grain Yield and Some Related Characteristics in Rice (Oryza sativa L.) Under Normal and Water Stress Conditions.

Drought is considered a major threat to rice production. This study aimed to determine the effects of drought stress on the estimates of heterosis and the combining ability of rice genotypes for the number of days to 50% heading, plant height, number of panicles per plant, panicle length, number of filled grains per panicle, and grain yield per plant. Field experiments were conducted at the Rice Research and Training Center, Kafr El Sheikh, Egypt, during the rice-growing season in 2018 and 2019. Eight rice genotypes (Giza178, Giza179, Sakha106, Sakha107, Sakha108, WAB1573, NERICA4, and IET1444) were crossed in a half-diallel cross in the rice-growing season in 2018, which yielded a wide range of variability in numerous agronomic traits and drought tolerance measurements. In 2019, these parents and their 28 F1 crosses were produced by employing a three-replication randomized complete block design under normal and water stress conditions. The results showed remarkable differences across the studied genotypes under normal and water stress conditions. Under both conditions, Sakha107 was the best general combiner for earliness and short stature. Giza179 and Sakha108 were the best general combiners for grain yield per plant and one or more of its characteristics. Furthermore, in both normal and water stress conditions, Giza179 exhibited the highest general combining ability effects for all attributes that were evaluated. Under normal and water stress conditions, the Giza179 × Sakha107 cross demonstrated substantial and desirable specific combining ability effects on all the examined traits, which suggested that it could be considered for use in rice hybrid breeding programs. Therefore, we recommend that these vital indirect selection criteria to be considered for improving rice grain yield under drought conditions.

Estimation and utilization of heterosis and heterobeltosis for yield and yield contributing traits in tossa jute hybrids (F1) derived from diverse germplasms

Estimation and utilization of heterosis and heterobeltosis for yield and yield contributing traits in tossa jute hybrids (F1) derived from diverse germplasms

Model definition for genetic evaluation of purebred and crossbred lambs including heterosis.

Crossbreeding is a common practice among commercial sheep producers to improve animal performance. However, genetic evaluation of U.S. sheep is performed within breed type (terminal sire, semi-prolific, and western range). While incorporating crossbred records may improve assessment of purebreds, it requires accounting for heterotic and breed effects in the evaluation. The objectives of this study were to: 1) describe the development of a paternal composite (PC) line, 2) determine the effect of direct and maternal heterosis on growth traits of crossbred lambs, 3) estimate (co)variance components for direct and maternal additive, and uncorrelated maternal environmental, effects, and 4) provide an interpretation of the estimates of random effects of genetic groups, and to use those solutions to compare the genetic merit of founding breed subpopulations. Data included purebred and crossbred records on birth weight (BN; n = 14,536), pre-weaning weight measured at 39 or 84 d (WN; n = 9,362) depending on year, weaning weight measured at 123 d (WW; n = 9,297), and post-weaning weight measured at 252 d (PW; n = 1,614). Mean (SD) body weights were 5.3 (1.1), 16.8 (3.9) and 28.0 (7.6), 39.1 (7.2), and 54.2 (8.7) kg for BN, WN (at the two ages), WW, and PW, respectively. In designed experiments, the Siremax, Suffolk, Texel, Polypay, Columbia, Rambouillet, and Targhee breeds were compared within the same environment. Estimates of heterotic effects and covariance components were obtained using a multiple trait animal model. Genetic effects based on founders' breeds were significant and included in the model. Percent estimates of direct heterosis were 2.89 ± 0.61, 2.60 ± 0.65, 4.24 ± 0.56, and 6.09 ± 0.86, and estimates of maternal heterosis were 1.92 ± 0.87, 4.64 ± 0.80, 3.95 ± 0.66, and 4.04 ± 0.91, for BN, WN, WW, and PW, respectively. Correspondingly, direct heritability estimates were 0.17 ± 0.02, 0.13 ± 0.02, 0.17 ± 0.02, and 0.46 ± 0.04 for BN, WN, WW, and PW. Additive maternal effects accounted for trivial variation in PW. For BN, WN, and WW, respectively, maternal heritability estimates were 0.16 ± 0.02, 0.10 ± 0.02, and 0.07 ± 0.01. Uncorrelated maternal environmental effects accounted for little variation in any trait. Direct and maternal heterosis had considerable impact on growth traits, emphasizing the value of crossbreeding and the need to account for heterosis, in addition to breed effects, if crossbred lamb information is included in genetic evaluation.

Prediction of Gene Action, Heterosis and Combining Ability to Identify Superior GMS Based Hybrids in Asiatic Cotton (G. arboreum L.)

The nature of gene action and combining ability is valuable in determining whether heterosis is fixable or predictable. Thus, to know the nature of gene action of seed cotton yield and its components and fibre quality parameters, seventeen parents (15 males and two genetic male sterile lines) and 30 F1 crosses (genetic male sterility based) were evaluated in a line x tester mating design of Asiatic cotton (Gossypium arboreum L). Sufficient variability among hybrids and their parents was found as the mean squares of genotypes for all the traits including fibre quality parameters investigated were significant. The total genetic variability was partitioned to general combining ability (GCA) and specific combining ability (SCA) effects. GCA was significant for male parents HD-123, RG-270, CISA-59, CISA-64, CISA-65, CISA-66 and LD-694 for seed cotton yield (SCY); HD-123, RG-286 and DLSA-24 for bolls per plant; HD-123, CISA-59, PAIG-8/3, DLSA-9 and LD-694 for boll weight; female parent DS-5, male parents HD-123, RG-18, CISA-65, and PAIG-8/3 for ginning outturn (GOT%); RG--270, RG-286, PAIG-8/3, DLSA-9 and LD-694 for 2.5% span length (mm); RG-286, CISA-59, CISA-66, PAIG-8/3 and LD-694 for lower micronaire value having finenessand HD-400, RG-270, RG-286, RG-341 CISA-60, CISA-66, PAIG-8/3 and LD-694 for tenacity (g/tex) which were considered as good general combiners. Similarly among 30 cross combinations, SCA was positively significant for 10 crosses for seed cotton yield, 10 crosses for boll number, 10 crosses for boll weight, 9 crosses for GOT(%), 10 crosses for 2.5% span length and 8 crosses for fibre strength (gt/tex).Cluster III of yield attributing traits, consisted of 9 crosses ( C3, C6, C18, C20, C26, C22, C23, C24, C30, and C8) showed the highest average seed cotton yield where as Cluster II of fibre quality traits consisted of 3 crosses ( C2, C12, C15) showed highest average GOT(%) with highest tenacity (g/tex). Cross DS-5 x HD 123for SCY and bolls per plant, DS-5 x DLSA 9 for boll weight, DS-5 x CISA 65 for GOT % , CISA-2 x CISA 66 for lower micronaire value (fibre fineness) showed significant estimation of heterosis in desirable direction and could be further utilized in the future breeding programme for specific trait improvement.

Hybrid vigour studies for root yield traits across the environments in Ashwagandha (Withania somnifera L.)

In the present experiment, 45 F1 hybrids of Ashwagandha were included in relation to investigate extent of heterosis for dry root yield and its attributing characters. The pooled ANOVA depicted the valuable amount of diversity existed among genotypes for all the characters. The significant estimates of heterosis in desirable direction were recorded in 22 hybrids over the mid parent, six hybrids over the better parent and six hybrids against the superior check (JA-134) for dry root yield, out of which the cross, UWS-309 × RVA-100 exhibited highest useful heterosis (17.42 %) for dry root yield across the environments, hence, the cross may be gainfully utilized.

Estimation of genetic parameters and heterosis through line × tester crosses of national sorghum varieties and local Indonesian cultivars

Abstract. Rachman F, Trikoesoemaningtyas, Wirnas D, Reflinur. 2022. Estimation of genetic parameters and heterosis through line × tester crosses of national sorghum varieties and local Indonesian cultivars. Biodiversitas 23: 1588-1597. Diverse gene sources possessed by local sorghum cultivars are potentially useful for superior varieties development. This study aimed to determine the genetic parameters and heterosis of sorghum lines derived from national varieties and local cultivars crosses. A total of eight F1 hybrids derived from line × tester mating design with four lines (PI-150-20A, Soraya 3 IPB, Kawali, Bioguma 1 Agritan) and two testers (Pulut 3 and Pulut 5) were used in the present study. This experiment was arranged in a randomized complete block design (RCBD) with three replications. Results showed that several agronomical important traits, such as plant height, leaf number, days to flowering, days to harvesting, panicle length, panicle diameter, and 1000-grain weight were significantly affected by additive gene action, while others by non-additive gene action. Based on field observation, three out of six parental lines showed the best performance of grain yields traits. Of these, Soraya 3 IPB × Pulut 5 and Bioguma 1 Agritan × Pulut 5 crosses were the best cross combination showing high values for both combining ability and heterosis parameters. These findings would help breeders to determine the selection methods for desirable traits and cross combinations to develop a new variety with high yield performance.

HETEROTIC ESTIMATION AND ADAPTABILITY OF TOMATO HYBRIDS FOR FRUIT YIELD AND ITS RELATED TRAITS IN PAKISTAN.

Current study is emphasizing on the estimation of heterosis for different yield attributing traits and adaptability of tomato hybrids. It was performed in the research area of VCRP, HRI, NARC Islamabad during 2018-2019. Crossing was completed among six parents followed by line × tester. The analyzed data depicted significant differences (P ≤ 0.01) among all the characters.Due to desirable high negative heterotic values hybrids Peto-86 × Nagina and Riograndi × Roma were found suitable for breeding early maturing hybrids. For plant height maximum positive heterosis was observed in Riograndi × Nagina, for no. of cluster/plant in Naqeeb × Roma, for traits like flower cluster-1, fruit cluster-1, fruit length & width and single fruit weight in Naqeeb × Continental while for yield Riograndi × Continental showed maximum heterosis. Therefore among 9 tested hybrids Naqeeb × Continental was found to be highly preferable and recommended for utilization in different breeding programmes.

Hybrid Seed Set in Relation with Male Floral Traits, Estimation of Heterosis and Combining Abilities for Yield and Its Components in Wheat (Triticum aestivum L.).

Breeding hybrids with maximum heterosis requires efficient cross-pollination and an improved male sterility system. Renewed efforts have been made to dissect the phenotypic variation and genetic basis of hybrid floral traits, although the potential of tailoring the appropriate flower design on seed setting is less known. To this end, elite wheat genotypes were crossed using a chemical hybridizing agent at different doses. A total of 23 hybrids were developed from a partial diallel design; and planted in an alpha lattice design with their parents at two locations in Morocco, for two years, to evaluate for yield components, heterosis and combining abilities. The 13.5 L ha−1 dose induced a maximum level of sterility (95%) and seed set showed large phenotypic variation and high heritability. In parallel, seed set showed tight correlation with pollen mass (0.97), visual anther extrusion (0.94) and pollen shedding (0.91) (p < 0.001), allowing direct selection of the associated traits. Using the combined data, mid-parent heterosis ranges were −7.64–14.55% for biomass (BM), −8.34–12.51% for thousand kernel weight (TKW) and −5.29–26.65% for grain yield (YLD); while best-parent heterosis showed ranges of −11.18–7.20%, −11.35–11.26% and −8.27–24.04% for BM, TKW and YLD, respectively. The magnitude of general combining ability (GCA) variance was greater than the specific combining ability (SCA) variance suggesting a greater additive gene action for BM, TKW and YLD. The favorable GCA estimates showed a simple method to predict additive effects contributing to high heterosis and thus could be an effective approach for the selection of promising parents in early generations.

Genetic parameters, heterosis, and breed effects for body condition score and mature cow weight in beef cattle.

Understanding the genetic relationship between mature cow weight (MWT) and body condition score (BCS) is useful to implement selection programs focused on cow efficiency. The objectives of this study were to estimate genetic parameters, heterosis, and breed effects for MWT and BCS. In total, 25,035 and 24,522 overlapping records were available for MWT and BCS on 6,138 and 6,131 cows, respectively, from the Germplasm Evaluation program, a crossbred beef population at the U.S. Meat Animal Research Center. Pedigree was available for 48,013 individuals. Univariate animal models were used to estimate heritabilities for each trait by parity. Bivariate animal models were used to estimate genetic correlations between parities within a trait and between traits within parities. Bivariate repeatability animal models were used to estimate genetic correlations between traits across parities. Estimates of heritability for different parities ranged from 0.43 ± 0.05 to 0.55 ± 0.07 for MWT and from 0.12 ± 0.03 to 0.25 ± 0.04 for BCS and were lower with the repeatability model at 0.40 ± 0.02 and 0.11 ± 0.01 for MWT and BCS, respectively. Estimates of repeatability were high for MWT (0.67 ± 0.005) and low for BCS (0.22 ± 0.006). Estimates of genetic correlation for MWT and BCS between parities were, in general, high, especially between consecutive parities. Estimates of genetic correlation between MWT and BCS were positive and moderate, ranging from 0.32 ± 0.09 to 0.68 ± 0.14. The direct heterosis estimates were 21.56 ± 3.53kg (P ≤ 0.001) for MWT and 0.095 ± 0.034 (P ≤ 0.001) for BCS. Ordered by decreasing MWT, the breeds ranked Brahman, Charolais, Angus, Simmental, Salers, Hereford, Santa Gertrudis, Chiangus, Brangus, Red Angus, Shorthorn, Maine-Anjou, Gelbvieh, Beefmaster, Limousin, and Braunvieh. Ordered by decreasing BCS, the breeds ranked Brahman, Red Angus, Charolais, Angus, Hereford, Brangus, Beefmaster, Chiangus, Salers, Simmental, Maine-Anjou, Limousin, Santa Gertrudis, Shorthorn, Gelbvieh, and Braunvieh. Estimates of breed differences for MWT were also adjusted for BCS (AMWT), and in general, AMWT depicted smaller differences between breeds with some degree of re-ranking (r = 0.59). These results suggest that MWT and BCS are at least moderately genetically correlated and that they would respond favorably to selection. Estimates of breed differences and heterotic effects could be used to parameterize multibreed genetic evaluations for indicators of cow maintenance energy requirements.

Study of Heterosis for Grain Yield and its Components Traits in Single Cross Derivatives of Maize (Zea mays L.)

The 45 F1 hybrids obtained by crossing in line x tester fashion were evaluated in three different environments along with parents and checks for grain yield traits and its component to harness the heterotic information over better parent and standard check. the number of hybrids depicted significant positive heterobeltiosis and relative heterosis on pooled basis were 38 and 40 respectively, for grain yield per plant. The estimates of standard heterosis for grain yield and its attributing traits showed that hybrid L14×T3 exhibited maximum estimates of significant positive standard heterosis suggesting that hybrid may be exploited before commercial release for confirmation of its superiority.

Estimates of breed additive, heterosis and epistasis genetic effects on milk production and reproductive traits from indigenous Borena and crosses with Holstein Friesian dairy cows at Holetta dairy research farm, Ethiopia

Estimates of breed additive, heterosis and epistasis genetic effects on milk production and reproductive traits from indigenous Borena and crosses with Holstein Friesian dairy cows at Holetta dairy research farm, Ethiopia

Combining ability and heterosis studies in different crop sites for yield and yield contributing traits in sorghum (Sorghum bicolor (L.) Moench)

Forty eight hybrids, utilizing six male sterile lines and eight restorers of Sorghum (Sorghum bicolor (L.) Moench) were evaluated for general and specific combining ability, variance components and standard heterosis. Among the lines ICSA 427 and ICSA 433 and testers ICSR 13009 and ICSR 13031 were found to be good general combiners for grain yield per plot and other yield contributing traits. The estimates of σ2gca and σ2sca suggested a non-additive genetic variance for all the traits studied. Most of the cross combinations showed higher magnitude of specific combining ability effects volving high × high (H × H) and high × low (H × L) combining ability effects of lines and testers for grain yield per plot and other yield contributing traits. The estimates of standard heterosis for grain yield per plot ranged from -49.53 and -50.46 (ICSA 435 × ICSR 13004) to 41.96 and 39.35 (ICSA 433 × ICSR 13043) over CSV-41 and CSH-16, respectively. Out of 48 cross combinations, six registered highly significant positive heterosis (over CSV-41 and CSH-16) for grain yield per plot. Key words: Sorghum, male sterility, heterosis, combining ability.