Single Hybrids Research Articles

Double cross hybrids could substantially supersede single cross hybrids for yield, fruit quality and tolerance to tomato leaf curl virus disease

ABSTRACT Recombination of commercially available hybrids could produce desirable segregants that act as sources of new alleles for tomato breeding. Seven commercial single cross (SC) hybrids of tomato (Solanum lycopersicum L.) were crossed in a half diallel fashion to obtain 21 double cross hybrids (DC) to estimate combining ability, mode of gene action and extent of heterobeltiosis for fruit yield, processing qualities and tomato leaf curl virus (ToLCV) disease severity traits. Predominance of non-additive gene action occurred in the control for all characters except for total soluble solids (TSS) content in fruit that was conditioned by both additive and non-additive gene action. Improvement of most traits in DC hybrids over SC hybrids occurred. Maximum heterotic effect in DC hybrids was for vitamin C content followed by lycopene content, fruit yield per plant, titratable acidity content, number of fruit per plant and percent disease index of ToLCV. Two good combiners, ‘PAN-1286’ and ‘Devi’ among SC hybrids were identified based on general combining ability effects and average performance. Commercial exploitation of DC hybrids, ‘TO-1458 × L-37’ and ‘NS-501 × TO-1458’ following multilocational testing in the tropics and subtropics might be useful. High yielding, ToLCV disease tolerant DC hybrids could be exploited in segregating generations to identify elite multi-parent advanced generation inter-cross (MAGIC) populations.

Studies on correlation and path co-efficient analysis of single cross hybrids in sweet corn

A total of 42 experimental hybrids generated by diallel mating design using 7 inbred lines of sweet corn were evaluated with parents and checks during Kharif 2019 at University of Agricultural Sciences, Dharwad. Green ear yield revealed a significant correlation in the positive direction with plant height, ear height, ear length, ear girth, number of kernel rows, and number of kernels per row at both genotypic and phenotypic levels, while a negative correlation was observed with days to 50% silking and Turcicum Leaf Blight. The highest value of correlation co-efficient for green ear yield was observed with green ear yield without husk, followed by the number of kernels per row and ear girth. However, there is no significant correlation between green ear yield and Total Soluble Solids. The genotypic correlation was found to be higher than the phenotypic correlation indicating high heritability of traits. Ear girth, ear height and the number of kernels per row displayed the highest positive direct effects on yield at the genotypic level and also manifested significantly positive indirect effects via plant height, ear height, green ear weight without husk, green fodder weight and the number of kernels per row. These three traits were likewise shown to have the most positive correlation with green ear yield. As a result, these attributes can be considered while selecting sweet corn genotypes for higher green ear yield.

Identification of SSR Markers Associated with Yield-Related Traits and Heterosis Effect in Winter Oilseed Rape (Brassica Napus L.)

The identification of markers responsible for regulating important agronomic traits in rapeseed supports breeding and increases the seed yield. Microsatellite (SSR) markers are mainly used as ‘neutral’ genetic markers but are also linked with many biological functions. The objective of this study was identification of microsatellite markers associated with important agronomic traits affecting the seed yield of winter oilseed rape and with the heterosis effect for these traits. The plant material consists of four parental lines, 60 doubled haploid (DH) lines, 60 single cross hybrids, and 60 three-way cross hybrids. The association between molecular markers and observed traits was estimated using regression analysis. Among 89 SSR markers, 43 were polymorphic, and 15 were selected for mapping because they demonstrated stability in both years of observation. These markers were physically mapped in the rapeseed reference genomes and their immediate vicinity was searched to identify candidate genes associated with the studied traits. Six markers (BrGMS3837, BnEMS1119, BrGMS2901, BnGMS0509, BrGMS3688, BrGMS4057), which showed a positive estimation effect in our association analysis, and thus increased the value of a given trait or heterosis effect, turned out to be linked with genes that could be responsible for the development and growth of plants.

Effect of treated sewage water and organic manure on growth indices, phenology, cob dimensions and economics of spring maize (Zea mays L.) in semi-arid region of Haryana, India

An experiment was conducted during spring 2020 at Student Farm, CCS Haryana Agricultural UniversityHisar, Haryana to study the effect of single cross hybrids, irrigation sources and organic manures on growthindices, phenology, cob dimensions and economics of maize. The experiment was laid out in split plotdesign with 3 replications consisting of two single cross hybrids(HQPM-1 and HQPM-5) and two irrigationsources (Canal water and Treated sewage water) in main plots while four levels of organic manure (Nomanure, 100% RDN though FYM, 100% RDN though vermicompost and 50% RDN though FYM + 50%RDNthough vermicompost) in subplots.HQPM-1 had earlier flowering, higher growth rate (absolute, crop andrelative), girth and length of cob, gross and net returns in comparison to HQPM-5. Similarly, application oftreated sewage water recorded earlier flowering, higher growth rates, cob dimensions and economics ascompared to canal water. So the treated water can be used for replacement of conventional water. Highestgrowth rates, cob dimensions, gross returns and earlier flowering was recorded with application of 100%RDN through vermicompost. However, highest net returns was achieved under 100% RDN through FYM.

Combining Ability and Heterotic Patterns of Tropical Early-Maturing Maize Inbred Lines under Individual and Combined Heat and Drought Environments.

Information on combining ability and heterotic patterns of multiple stress-tolerant inbred lines are fundamental prerequisites for devising appropriate breeding strategies for the development of climate-resilient maize hybrids. In the present study, we evaluated 150 single cross hybrids derived from the North Carolina Design II (NCD II) along with six commercial checks under terminal drought stress (TDS), heat stress (HS), and combined drought and heat stress (CHDS)conditions. The objectives of the study were to: (i) determine the combining ability of the inbred lines and identify the best testers across the stresses; (ii) classify the inbred lines into heterotic groups (HGs) based on the general combining ability of multiple traits (HGCAMT) and sequencing-based diversity array technology (DArTseq) and (iii) assess the performance and stability of the lines in hybrid combinations. The inbred lines showed significantly (p < 0.01 and p < 0.05) positive and negative general combining ability (GCA) and specific combining ability (SCA) effects for grain yield (GY) and most other measured traits. The inbred line TZEI 135 displayed relatively larger positive GCA effects for GY when mated either as male or female and was identified as the best tester. TZEI 135 × TZEI 182 was identified as the best single-cross tester across environments. Results of the assessment of the relative importance of GCA and SCA effects revealed the predominance of additive gene action over the non-additive. Six HGs of inbreds were identified using the HGCAMT and three, based on the DArTseq marker genetic distance method, were the most efficient. The best hybrids in this study significantly out-yielded the best checks by 21, 46, and 70% under CHDS, HS, and TDS, respectively. These hybrids should be extensively tested in on-farm trials for possible commercialization in sub-Saharan Africa.

Genotype X Environment Interaction Studies in Single Cross Maize Hybrids for Quality Traits under Different Environments

Sixty eight genotypes of maize (48 hybrids, 16 parents and 4 checks were evaluated under three different environments to test their stability. Variance due to genotypes, environments and genotype x environment interactions were found significant for oil content, starch content and protein content. Regression approach by Eberhart and Russel 1966 used to investigate the nature of G x E interaction and for identifying genotypes possessing general and specific adaption. None of the hybrids had stability for all quality traits. For Grain Starch content hybrid EI-1155-1 x EI-2416, for oil content hybrid EI-670-2 x EI-2403 and for Protein content hybrids EI-2187 x EI-2403, EI-536-3 x EI-2403, EI-2176 x EI-561-2,EI-2173 x EI561-7 had higher mean values, non significant deviation from regression and regression coefficient around unity (bi=1) indicating the stable performance in different environment and wider adaptability.

Productivity-based assessment of tolerance to high plant density stress in tropical maize (Zea mays L.) inbred lines and their single cross hybrids

High density planting (HDP) has been used extensively to achieve high productivity in temperate maize and the same can be exploited in tropical/subtropical maize. Based on two years field evaluation of tropical maize inbred lines under different planting regimes, this study led to identification of high plant density stress tolerant (at 30 percent higher plant population than cultural practice) high yielding maize inbreds. Leaf angle of first leaf above ear, anthesis-silking interval, cob length, and 1000 kernel weight were found directly affecting grain yield under HDP. Specific cross combinations exhibiting higher grain yield under HDP (approx. 15-20 percent), than normal planting practices, were identified. This is the first report on systematic development and evaluation of parental lines under high plant population and to generate high plant density stress tolerant hybrids in tropical maize.

Comparison of Maize Genotypes Using Drought-Tolerance Indices and Graphical Analysis under Normal and Humidity Stress Conditions.

This study aimed to identify drought-tolerant genotypes and to evaluate and compare the response of genotypes under normal conditions and humidity stress. The experiment was conducted in a Randomized Complete Block Design (RCBD) on 12 commercial single cross hybrids of maize (Zea mays L.) with three replications in two separate experiments under normal and stress conditions. GT biplot was used to compare genotypes under normal conditions and humidity stress. Based on the polygon diagrams’ graphical analysis, KSC206, KSC704, KSC705 and KSC706 genotypes were identified as desirable hybrids. The ranking diagram of genotypes based on ideal genotype also showed that the KSC704 genotype had high desirability in all evaluated traits in normal and stress conditions. TOL, MP, HARM, GMP, SSI and STI indices were used to identify drought-tolerant genotypes, and the genotypes were ranked based on this index. Based on this, KSC260, SC302 and KSC400 hybrids were selected as resistant hybrids. Based on the correlation analysis between drought-tolerance indices, a positive correlation was observed between MP, GMP, HARM and STI indices. Based on the analysis of the PCA on the indices, the first and second principal components were given the titles of grain yield tolerance component under humidity stress conditions and grain yield stability component under normal humidity conditions, respectively. KSC704 was superior to other hybrids in terms of grain yield under normal conditions and stress, and the KSC260 hybrid was identified as a tolerant hybrid in terms of all studied traits under drought stress.

Genetic Diversity among Single, Double, And Triple Cross Hybrids in Beit Alpha Cucumber (Cucumis sativus)

Genetic variation was investigated in fifteen single, eighteen three-way, and nine double hybrid crosses and their parents along with nine elite commercial cucumber hybrids. Six lines (NS5, NS9, NS17, NS29, NS31, and NS33) were used to develop these cross hybrids. Based on AFLP and SSR analysis, the studied cucumber genotypes have a narrow genetic base. The results also showed genetic differentiation compared to commercial varieties. Out of 1352 bands produced from 12 AFLP primer pairs, only 47 were polymorphic. Similarly, out of 26 SSR primers, only one primer was polymorphic. The highest heterozygosity index (0.6044), polymorphic information content value (0.5392), and marker Index (0.6044) were observed with M-CTT_E-AAG AFLP primer combination, while the highest effective multiplex ratio (2.8246) and resolving power (4.8421) were observed with M-CTC_E-AGC AFLP primer combination. Genetic distance estimation revealed clear distinctiveness of the studied genotypes with the control varieties. The cluster analysis by UPGMA showed two main clusters covering 84% of the studied genotypes grouped. This research shows that double and three-way hybrid crosses can be used in cucumber hybrid breeding.

Chalcogen···Chalcogen Bonding in Molybdenum Disulfide, Molybdenum Diselenide and Molybdenum Ditelluride Dimers as Prototypes for a Basic Understanding of the Local Interfacial Chemical Bonding Environment in 2D Layered Transition Metal Dichalcogenides

An attempt was made, using computational methods, to understand whether the intermolecular interactions in the dimers of molybdenum dichalcogenides MoCh2 (Ch = chalcogen, element of group 16, especially S, Se and Te) and similar mixed-chalcogenide derivatives resemble the room temperature experimentally observed interactions in the interfacial regions of molybdenites and their other mixed-chalcogen derivatives. To this end, MP2(Full)/def2-TVZPPD level electronic structure calculations on nine dimer systems, including (MoCh2)2 and (MoChCh′2)2 (Ch, Ch′ = S, Se and Te), were carried out not only to demonstrate the energetic stability of these systems in the gas phase, but also to reproduce the intermolecular geometrical properties that resemble the interfacial geometries of 2D layered MoCh2 systems reported in the crystalline phase. Among the six DFT functionals (single and double hybrids) benchmarked against MP2(full), it was found that the double hybrid functional B2PLYPD3 has some ability to reproduce the intermolecular geometries and binding energies. The intermolecular geometries and binding energies of all nine dimers are discussed, together with the charge density topological aspects of the chemical bonding interactions that emerge from the application of the quantum theory of atoms in molecules (QTAIM), the isosurface topology of the reduced density gradient noncovalent index, interaction region indicator and independent gradient model (IGM) approaches. While the electrostatic surface potential model fails to explain the origin of the S···S interaction in the (MoS2)2 dimer, we show that the intermolecular bonding interactions in all nine dimers examined are a result of hyperconjugative charge transfer delocalizations between the lone-pair on (Ch/Ch′) and/or the π-orbitals of a Mo–Ch/Ch′ bond of one monomer and the dπ* anti-bonding orbitals of the same Mo–Ch/Ch′ bond in the second monomer during dimer formation, and vice versa. The HOMO–LUMO gaps calculated with the MN12-L functional were 0.9, 1.0, and 1.1 eV for MoTe2, MoSe2 and MoS2, respectively, which match very well with the solid-state theoretical (SCAN-rVV10)/experimental band gaps of 0.75/0.88, 0.90/1.09 and 0.93/1.23 eV of the corresponding systems, respectively. We observed that the gas phase dimers examined are perhaps prototypical for a basic understanding of the interfacial/inter-layer interactions in molybdenum-based dichalcogenides and their derivatives.

Sample size for canonical correlation analysis in corn

The canonical correlation analysis has been successfully used in many areas aiming to extract important information from a pair of data sets. Thus, the objective of this work was to determine the sample size (number of plants) required to estimate the canonical correlations in corn characteristics. Six characteristics were measured in 361, 373, and 416 plants, respectively, of the single, three-way and double cross hybrids of the 2008/2009 crop year and in 1,777, 1,693, and 1,720 plants, respectively, of the single, three-way, and double cross hybrids (2009/2010 crop) (six cases). The canonical correlation analyses were carried out between characteristics group of the plant architecture (plant height at harvest and ear insertion height) versus grain production (hundred grains mass and grains mass per plant) (scenario 1), and dimensions of ear (ear length and ear diameter) versus grain production (hundred grains mass and grains mass per plant) (scenario 2). The sample size (number of plants) for the estimation of canonical correlations was determined by resampling with replacement and application of the model linear response with plateau. Measuring 270 plants is sufficient to estimate the canonical correlation between groups with two characteristics in each group for corn. This sample size can be used as reference for reliable canonical correlation analysis.

Effect of reciprocal crosses on grain yield and other agronomic traits in maize

The goal of this experiment was to examine a possible influence of reciprocal crosses on grain yield and some morphological traits in maize. Field trials were set up on three locations (Zemun Polje, Pancevo, Becej) during 2015 and 2017. Five elite inbred lines were selected in order to produce hybrid combinations for the trial, two of them were of Lancaster origin and used as tester lines (ZPT1, ZPT2), while remaining three had a Non Lancaster origin (ZPL1, ZPL2 and ZPL3). By performing reciprocal crossings between Lancaster and non Lancaster inbred lines, twelve single cross hybrids were produced for the trial. Trials were set up on three locations during two years and grain yield, grain moisture, plant height, ear height and mass of 1000 kernels were analyzed. Location, year and reciprocal crosses were significant factors for all examined traits. Reciprocal crosses had statistical significance on two hybrid combinations in terms of grain yield and grain moisture. SNPs molecular markers were used to assess the genetic diversity of the inbred lines involved in this experiment. When it comes to plant height and mass of thousand kernels, a statistically significant difference was observed in one hybrid combination. The largest reciprocal differences between original and reciprocal hybrids were recorded in grain yield, which were statistically significant for the crosses ZPH4/ZPH4R and ZPH2/ZPH2R (20.03% and 19.49% respectively). The ZPH2/ZPH2R hybrid combination is the combination with the statistically significant differences between the original and reciprocal hybrid, for all evaluated traits except for grain moisture. Reciprocal hybrids ZPH5/ZPH5R and ZPH6/ZPH6R with ZPL3 as their maternal inbred line didn?t express a statistically significant differences between both variants, e.g. their reciprocal effect was low.

Mega-environment analysis of maize breeding data from Brazil

The development and recommendation of single cross maize hybrids (SH) to be used in extensive land areas (mega-environments), and in different crop seasons requires many experiments under numerous environmental conditions. The question we asked is if the data from these multi-environment experiments are sufficient to identify the best hybrid combinations. The aim of this study was to critically analyze the phenotype data of experiments of yield, established by a large seed producing company, under a high level of imbalance. Data from evaluation of 2770 SH were used from experiments conducted over four years, involving the first and second crop seasons, in 50 locations of different years and regions of Brazil. Different types of analysis were carried out and genetic and non-genetic components were estimated, with emphasis on the different interactions of the SH with the environments. Results showed that the coincidence of common hybrids in these experiments is normally small. The estimates of the correlations between of the hybrids coinciding in the environments two by two is of low magnitude. The hybrid × crop season interaction was always expressive; however, the interactions of hybrids and other environmental variables were also important. Under these conditions, alternatives were discussed for making with the information obtained from the experiments, can be more efficient on the process to obtain new hybrids by companies.

Phenotypic Screening of Okra Hybrids Against Yellow Vein Mosaic Disease and Shoot and Fruit Borer Under Field Conditions

The present study aimed to phenotypically screen the okra hybrids and their parents so as to identify tolerant or resistant genetic material against yellow vein mosaic disease (YVMD) and okra shoot and fruit borer (OSFB). The present study included a total of 55 single cross hybrids, 16 parents, and one hybrid check “OH-102” which were evaluated during monsoon 2019 at three locations (Navsari, Achhalia, and Vyara) in Gujarat (India) in RBD design. The number of plants and fruits affected in each genotype was counted at final harvest and percent incidence calculated for YVMD and SFB. Okra genotypes were screened to know their response on the basis of plant and fruit damage severity scale. Among 72 genotypes (55 hybrids + 11 lines + 5 testers), none was free from YVMD and SFB incidence. Among the parents, ‘Arka Anamika’ and ‘Arka Abhay’, categorized as moderately resistant to YVMD and SFB at all test locations, were identified as the most promising donors for future breeding. Among 55 hybrids and check 22, 17, and 14 hybrids and check “OH-102” categorized as moderately resistant for YVMD, 15, 13, 9 hybrids for Okra Shoot Borer (OSB) and 13, 15, 16 hybrids for Okra Fruit Borer (OFB) and check “OH-102” categorized as fair resistance at Navsari, Achhalia and Vyara, respectively. The least YVMD and OSFB incidence in hybrids showed relatively high/ average yield performance for fruit yield per plant at all locations, so these can be used in the further future breeding program.

Heterotic groups for identifying of suitable combiners in sunflower using top-cross

The study was conducted in order to identify the suitable parental inbred lines using top cross method for improvement of new sunflower F1 single cross hybrids at research field of Seed and Plant Improvement Institute in Karaj, Iran during two Crop season (2018 and 2019). Experimental materials consisted of 31 restore lines and 43 cytoplasmic male sterile lines which were crossed with A1221 and R14 as the testers respectively. The developed F1 hybrids were evaluated for GCA of three breeding objectives i.e. flowering time, plant height and grain yield during two years replicated trials. Cluster analysis revealed two heterotic groups in which the restorer lines; R22, R24 and R38 (Grain yield of 33, 32 and 31 g head-1 respectively) and three CMS lines; A32, A370 and A110 (Grain yield of 47, 44 and 43 g head-1 respectively) were identified as the suitable restorer and cytoplasmic male sterile line for improvement of new sunflower single cross hybrids. Evaluation of specific combing ability of the resulted combinations will reveal the efficiency of this selection in the following generation.

Impact of Different Nitrogen Levels to the Grain Yield and Yield Components of Some Corn (Zea mays L.) Hybrids

Aims: The study was designed to elucidate the effect of different nitrogen (N) fertilizer levels on five different maize cultivars.&#x0D; Study Design: A split plot experimental design in randomized complete blocks (RCBD) with three replicates. Arrangement of seven nitrogen levels and five single cross hybrids were compared. Main plots were nitrogen levels and subplots were varieties.&#x0D; Place and Duration of Study: College of Agricultural Engineering Sciences at the University of Duhok, Iraq. The study was undertaken fromMarch– August 2021.&#x0D; Methodology: At the present research, five single cross-hybrid corn varieties were used, which were: CADZ, DKC6050, DRACHMA, MYIMY and ZP6468D. Arrangement of seven nitrogen fertilizer levels were 0, 50, 100, 150, 200, 250 and 300 kg N ha−1. The following features were studied: plant height, leaf area index, thousand kernel weight, total grain yield, total chlorophyll, protein% and oil %.The collected data were projected to SAS software program for analysis. The significant differences between treatment means were calculated using Duncan’s multiple ranges.&#x0D; Results: It was reveal that there were significant effect of different nitrogen fertilizer levels, maize genotypes as well as the interaction of nitrogen and genotype of maize (P&lt;.01) for plant height, leaf area index, 1000 kernel weight, total grain yield, total chlorophyll and protein %. However, There were no significant differences between different maize genotypes as well as different nitrogen fertilizer levels (P&gt;.05) with oil %, but the interaction of nitrogen and genotype of maize was significant (P&lt;.01).&#x0D; Conclusion: Increasing the amount of nitrogen had better effect on studied characteristics of different maize varieties, in which adding 300 kg nitrogen had optimum results. In considering the response of maize varieties to nitrogen, the best variety was DRACHMA genotype while the worst variety was CADZ genotype, however this hybrids was superior in some traits.

Selection of S3 progenies of super sweet corn based on agronomic performance of topcrosses

ABSTRACT The aim of this study was to select S3 progenies of super sweet corn based on agronomic performance, evaluated in topcrosses with the narrow genetic base tester Honey Sweeter (Seminis®). The experiment was carried out in Guarapuava-PR. We evaluated 22 topcross hybrids and three checks, in two sowing times, in randomized blocks design with three replications. Six traits were evaluated: total yield of husked ears, commercial yield of husked ears, grain yield, grain length, ear diameter and total soluble solids content. Considering the set of evaluated traits, the topcrosses with progenies D2-07, D3-28, D4-53 and D5-24 were superior to the others; therefore, these progenies should continue in the inbreeding process and be evaluated in crosses with elite inbred lines with potential to generate competitive super sweet corn single hybrids.

Heterosis in relation to genetic divergence in short duration maize (Zea mays L.)

Thirteen lines and three testers were used to produce 39 single cross maize hybrids by line Ítester mating design. The genetic divergence among thirteen lines and three tester of maize were estimated by using Mahalanobis D2 statistic for twelve characters. The genotypes were grouped into five clusters. Cluster I comprised 12 parental genotypes (L1, L2, L3, L4, L5; L6, L7, L8, L9, L11; L12, L13), while Cluster II (T3), III (T1), IV (L10) and V (T2) were mono-genotypic, suggesting more variability in genetic makeup of the genotypes included in these clusters. The correlation coefficients and linear regressions were used to know the effects of parental genetic distance in determining heterosis and per se performance of the hybrids. Parental genetic distance exhibited significant negative association and significant linear regression along with very low coefficient of determination with better parent heterosis (BPH) and non-significant with per se performance of the hybrids. The present investigation, therefore, the parental genetic distance has significant role in determining heterosis and hybrid performance in kharif maize.

Understanding Heterosis, Genetic Effects, and Genome Wide Associations for Forage Quantity and Quality Traits in Multi-Cut Pearl Millet.

Pearl millet is an important food and fodder crop cultivated in the arid and semi-arid regions of Africa and Asia, and is now expanding to other regions for forage purpose. This study was conducted to better understand the forage quantity and quality traits to enhance the feed value of this crop. Two sets of pearl millet hybrids (80 single cross hybrids in Set-I and 50 top cross hybrids in Set-II) along with their parents evaluated multi-locationally for the forage-linked traits under multi-cut (two cuts) system revealed significant variability for the forage traits in the hybrids and parents. The mean better parent heterosis (BPH) for total dry forage yield (TDFY) was 136% across all the single cross hybrids and 57% across all the top cross hybrids. The mean BPH for in vitro organic matter digestibility (IVOMD) varied from −11 to 7% in the single cross hybrids and −13 to 11% in the top cross hybrids across cuts. The findings of TDFY and IVOMD heterosis in these sets indicated the potential of improvement of the hybrid cultivars for forage quantity and quality in forage pearl millet. The parental lines single cross parent (SCP)-L02, SCP-L06, and top cross parent (TCP)-T08 found superior in the forage quantity and quality traits can be utilized in the future breeding programs. Most of the forage traits were found to be controlled by using the non-additive gene action. A diverse panel of 105 forage-type hybrid parents (Set-III) genotyped following genotyping by sequencing (GBS) and phenotyped for crude protein (CP) and IVOMD under multi-cuts for 2 years identified one stable significant single nucleotide polymorphism (SNP) on LG4 for CP, and nine SNPs for IVOMD distributed across all the linkage groups except on LG2. The identified loci, once validated, then could be used for the forage quality traits improvement in pearl millet through marker-assisted selection.

Study of Combining Ability and Hybrid Vigor in Many Maize lines Zea mays L

In this study, nine pure maize lines were tested, in the analytical program (Line X Tester), during spring season 2020 to obtain individual hybrids which are 20. Parents and the resulting individual hybrid seeds were cultivated in the autumn season 2020 in accordance with random complete block design R.C.B.D. in three replicates to estimate the general and specific combining ability, some genetic parameters, and study the hybrid vigor by the best parents. The statistical analysis results showed significant differences between parents and individual hybrids for every studied character. Tester (ART-B-17) showed superiority with the highest positive effect of the general combining ability for grains number per row, weight of 300 grains and grains yield per plant where it gave 51.81, 7.71, and 45.74 respectively. The line (Zm4) has the most desired effect with regard to the general combining ability for the parameters; the hight of upper cob, plant height, number of grans per raw, number of cobs per plant and, weight of 300 grains, and single plant grains yield (10.53, 11.48, 2.89, 0.08, 29.28) respectively. The hybrid (Zm3 × ART-B-17) gave the highest wanted effect for the specific combining ability for the following traits; the height of upper cob, number of cobs per plant and single plant grains yield 13.34, 0.15 and 48.46 respectively. The genetic analytical results showed the presence of additive non-additive effects that control the parameters inheritance. Percentages of broad and narrow sense heritability for grains crop parameter reached 100 % and 30.95% respectively, while the average degree of dominance for the same parameter reached 2.11. the hybrid (Zm4 × S6) achieved the highest positive hybrid vigor for single plant grains yield (64.45%). In conclusion, this study showed the possibility to use some dominant parental crosses to obtain single hybrids with high grain yield because the single plant grains yield parameter was complying the effect of highly dominant genes.