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Evaluation of Combining Ability for Some New Yellow Maize Inbred Lines Using Line X Tester Model
... Combining ability is a useful biometric tool to plant breeders for formulating efficient breeding programs 268 (Hallauer and Miranda 1981). Line x tester analysis by (Kempthome 1957) has widely been used for evaluation of inbred lines (Singh et al 2013, Jahan et al 2014, Rastgari et al 2014, El-Ghonemy 2015, Gamea 2015, Kumar et al 2015, Hassan et al 2016, Baudh Bharti et al 2017, Ismail et al 2018, Darshan and Marker 2019, Sharma et al 2019and Badr et al 2022. Classifying maize inbred lines into heterotic groups is the initial step in maize breeding due to maximizing the exploitation of heterosis by determining the relationship among the diverse inbred lines (Menkir et al 2004, Fan et al 2009, Legesse et al. 2009and Mosa et al 2017. ...
The identification of the best combiner lines in the breeding programe is important. Thus, new nineteen white maize inbred lines were crossed as female parents with two inbred lines as testers, i.e. SK-9 and Sk-13 at Sakha Agricultural Research Station, Field Crops Research Institute, Agricultural Research center during 2020 growing summer season. The 38 crosses with the commercial check hybrid SC 10 were evaluated at three locations, i.e. Sakha, Sids and Mallawy Research Stations during 2021 growing season. A randomized complete block design with three replications was used. The data were collected on number of days to 50 % silk emergence (DTS), plant height (PH) and grain yield per feddan (GYPF). The results showed that, locations (possessed high GCA effects for grain yield and (L-3, L-12 and L-13) showed desirable GCA effects for both earliness and short plant. The cross L-1 x SK-9 possessed desirable SCA effects and they also out-yielded, significantly, the check hybrid SC 10. Thus, this cross could be utilized for hybrids breeding program. The parental inbred lines were grouped into two groups based on heterotic group specific and general combing ability (HSGCA) method for (GYPF) trait. The group one was for tester SK-9 These groups could be used in a breeding program for selecting the best parents to make crosses in other combinations.
Improving maize (Zea mays L.) genotypes for higher productivity and tolerance to drought stress depends mainly on physiological and molecular markers. Therefore, this study aims at breeding maize for drought tolerance and high potentiality by selection based on molecular markers, photosynthetic parameters; and easy graphic methods that help in selecting elite genotypes across diverse environments. An 8 × 8 half diallel analysis was used at two locations involving drought and normal irrigation treatments to study parental genetic diversity (GD) and combining ability (general combing ability [GCA] and specific combining ability [SCA]) in F1 of maize. Fingerprinting of parents was made using simple sequence repeat (SSR) markers. Fifty‐eight alleles were ranged from two to five alleles per locus with an average of 0.63 alleles per locus. The average of polymorphic information content (PIC) was 0.63. Cuvette temperature (oc) was lowest by the cross L14 × L36. The cross L8 × L34 expresses the highest value for Quantum sensor (μmol m–2 s–1), net CO2 assimilation rate and chlorophyll content. As for leaf diffusive resistance (LDR) four crosses exhibited significant desirable LDR values. Concerning rate of leaf transpiration (LTR) (μg cm⁻² S⁻¹) the cross (L5 × L104) gave the lowest value. Most hybrids exhibited desirable values for drought susceptibility index. For grain yield plant–1, five F1 crosses, that is, L5 × L34, L8 × L14, L8 × L14, L30 × L104, and L36 × L104 expressed the most desirable SCA effects. These crosses are promising in maize breeding programs. Based on GGE biplot analysis, genotype nos. 8 and 10 exhibited the highest grain yield plant⁻¹ and ranked the first across all environments.
Fifteen inbred lines were crossed to three testers of maize to estimate combining ability effects for maturity and yield traits. The produce 45 crosses, S.C. 168 and T.W.C. Giza 368 were evaluated across two years at the Farm of Faculty of Agriculture, Moshtohor, Benha University in RCBD with 3 replicates. Mean squares due to year (Y) genotypes (G), crosses (C), testers (T), inbred lines (L), line x tester (LxT) and interaction variance for C, L, T and LxT with (S) were significant (P>0.05) for most studied traits. Non-additive gene action (δ 2 SCA) is more pervading in determining inheritance of the most traits. The non-additive type of gene action is fluctuated by year changed more than additive. The inbred lines M. 645a (L4), M. 653 (L5), and M. 674 (L11) showed desirable ĝi for early maturity and grain yield plant-1. The crosses M.221xM.653, M.221xM.655b, M.221xM.657, M.221xM.671, M.221xM.674 and M.221xM.677 exhibited out-yielded SC 168 reached 9.96%, 11.35%, 12.53%, 8.32%, 11.80% and 4.80%, respectively across years. TWC (SC M 200xM418)xM.653 and (SC M200xM418)xM.674 showed superiority than TWC 368 being 9.11% and 3.78%, respectively. The eight superior hybrids along with SC168, SC hytech 2066, TWC 368 and TWC 352 were evaluated in 2019 year at various environments using RCBD with 3 replicates to identify suitable adapted maize hybrids. The main effects of genotypes, environments and their GxE interaction were highly significant (P<0.01). Hybrids M. 221 x M. 674, M. 221 x M. 655b, SC hytech 2066 and SC 168 were the most crosses stable phenotypically and genetically across environments.
Eight inbred lines of white maize were crossed in half diallel scheme in 2016 season to assess mean performance, general (GCA) and specific (SCA) combining ability and their interaction with locations. Two experiments were conducted at two locations, viz. Moshthor, (L 1) and Sohag (L 2) using RCBD with 3 replications in season 2017. Each block consisted of 28 F 1 hybrids along with the single cross SC 10. Location mean squares for all traits under study were significant with values in L 1 higher than those in L 2 for grain yield plant-1. Significant hybrid mean squares were observed for all traits in both and across the studied locations, except for shelling% at L2. Significant hybrid x location mean squares occurred for all traits, except for No. of kernels row-1. The crosses P 2 xP 3 , P 1 xP 7 , P 6 xP 8 , P 2 xP 4 , P 1 xP 8, P 4 xP 8, and P 3 xP 5 exhibited significant and positive superiority over SC 10 mean value for grain yield across the two locations and surpassed the check hybrid by 18.19, 18.13, 15.33, 14.97, 14.23, 11.88 and11.72%, respectively. GCA and SCA mean squares were significant for all studied traits, except for GCA concerning No. of rows ear-1 at L 1 and ear diameter at L 1 and combined across locations, SCA at L 2 for No. of rows ear-1 and shelling%. A large part of total variability for ear height, 100-kernel weight and ear weight plant-1 was non-additive gene action. On the contrary, additive and additive x additive gene action was associated with grain yield plant-1. GCA×L and SCA×L interaction mean squares were significant for most studied traits. P3 and P8 expressed positive and significant ĝ i effects for ear and grain yields. The most desirable inter and intra-allelic interactions (ŝ ij effects) were obtained by the combinations; P 1 xP 7 , P 3 xP 5 and P 4 xP 8 for grain yield and ear weight plant-1 .
This investigation was carried out to study the combining ability effects of 18 parents of maize (15 inbred lines and 3 testers) crossed in line x tester scheme for phonological, plant and yield characteristics. A yield trial included the 45 top crosses, 15 inbred lines, 3 testers along with the two check hybrids S.C. 168 and TWC 352. The experiment was conducted at two planting dates on 15 th May and 15 th June at the Agric. Res. and Experimental Station of the Fac. of Agric., Moshtohor Benha University. The randomized complete blocks design with three replications was used in this study. Significant mean squares due to crosses (C), inbred lines (L), testers (T) and line x tester (LxT) were found for most studied traits of both and across sowing dates. Variance for C, L, T and LxT with sowing dates interaction on the most studied traits was significance. δ 2 SCA played the major role in determining the inheritance of all traits. The magnitude of the interaction of δ 2 SCA x sowing date (SD) was generally higher than for δ 2 GCA x SD. This finding indicates that non-additive is more affected by SD than additive and additive x additive. Three crosses exhibited significant superiority over high check hybrid S.C. G 168. The best top crosses were T3xL2 and T3xL15 at both and across sowing dates. Also, ten top crosses at combined analysis did not differ significantly than the best check hybrid for the mention trait. L2, L7, L14 and L15 were good general combiners for grain yield plant-1 and L9, L10 and L13 for earliness. The top-cross T1 with each of inbred lines 2, 5 and 6, T2 with each of L1 and L12 and T3 with each of L3,L4 and L12 for earliness; T1xL11, T1xL12, T1xL14, T2xL3, T2xL12 and T3xL2 for grain yield plant-1 gave the best ij S ^ effects.
Twenty one hybrids obtained from seven lines x three testers crossing fashion were analysed for specific combining ability effects (sca), heterosis and nature of gene action at two nitrogen (N) levels. The hybrids UMI 1008 x UMI12 (L1 x T1), UMI 4 x UMI 564 (L3 x T2), UMI 1007 x UMI 564 (L4 x T2), UMI 54 x UMI 826 (L5 x T3) and UMI 919 x UMI 12 (L7 x T1) recorded desirable per se performance, specific combining ability effects (sca) and heterosis for yield and most of the yield components in N1 (100 kg/ha) level as well as N2 (200 kg/ha) level. These five hybrids hold promise for exploitation under nitrogen stress. The hybrids
UMI 1008 x UMI 12, UMI 1007 x UMI 564, UMI 54 x UMI 826 and UM1 919 x UM1 12 had desirable per se performance, sca
effects and heterosis for days to anthesis, days to silking and grain yield at both N1 and N2 levels. Hence, these hybrids also need due consideration for promotion under nitrogen stress rainfed condition. Predominance of non-additive gene action revealed by the yield and its component traits indicated the possibility of exploiting promising hybrids identified for heterosis breeding.
Field experiments were conducted at the University of Ilorin Teaching and Research Farm in 2005 and 2006 cropping seasons with the objective to evaluate the combining ability for maize grain yield and other agronomic characters in 10 open pollinated maize varieties, which have been selected for high yield and stress tolerance. General combining ability (gca) and year (y) effects were significant for all the parameters except plant height, while specific combining ability (sca) and gca x year effects were significant only for grain yield. However, Tze Comp4 Dmr Srbc2, Tze Comp4 C2 and Acr 94 Tze Comp5 which are good general combiners for maize grain yield, also showed positive significant gca x year effects for flowering traits. Significant sca x year interaction effects were recorded for maize grain yield and days to flowering, with Hei 97 Tze Comp3 C4 combining very well with 3 parents (Acr 90 Pool 16-Dt, Tze Comp4-Dmr Srbc2 and Tze Comp4 C2). These parents and their hybrids probably have genes that can be introgressed into other promising lines in developing early maturing and high yielding varieties for cultivation in the Nigeria savannas.
The chapter discusses the use of genotype-by-environment interaction for crop cultivar development. The chapter begins with definitions of genotype, environment, and phenotype, and discusses the influence of environment on heredity that may result in modification of a phenotype and lead to genotype-environment (GE) interaction. Some terms from ecological genetics are used and explained. The chapter discusses the causes of genotype-environment interaction and ways to deal with it, stability statistics, and ways to exploit or minimize interaction. A crop cultivar development program has two major components—crop breeding methodology and performance evaluation of improved cultivars in target areas. Implications of GE interaction in breeding are discussed. The concepts of stability are presented. Methodology for identifying stable genotypes and environmental factors that may be responsible for stable or unstable performance is also presented. .
The aim of this study was to assess how low nitrogen and drought stresses affect genetic parameters of grain yield and endosperm hardness of QPM. Twelve inbred lines were acquired from CIMMYT and used to generate 36 single cross hybrids with North Carolina Design II procedures. The single crosses were evaluated at Kiboko in Kenya and Rubona in Rwanda in 2005 and 2006 cropping seasons under optimum, low nitrogen and drought conditions. Observations were performed on grain yield and endosperm hardness. The results showed that gene action on the grain yield was predominantly non-additive and maternal, whereas that of the endosperm hardness was predominantly additive and maternal. Low nitrogen and drought changed tile proportions of different genetic effects. They changed as well the magnitudes and direction of General Combining Abilities (GCAs) of lines and Specific Combining Abilities (SCAs) of crosses. It was possible to have together, significant and positive SCAs for grain yield and significant and negative SCAs for endosperm hardness. Crosses with significant and positive SCAs for gram yield and significant and negative SCAs for endosperm hardness are candidates to use in QPM production, especially in drought and low nitrogen prone areas.
A field experiment was carried out to study the grain yield and Nitrogen Use Efficiency (NUE) components of 16 inbred lines of exotic yellow maize and their crosses. The experiment was cropped at two nitrogen fertilizers; low (70 kg f-1) and high (140 kg f-1), split-plot design was used. The results indicated that, all measured traits were affected significantly by N levels, genotypes and the interaction, except days to 50% tasseling and silking of inbred lines which were not affected by N levels and the N x genotype interaction. N deficiency caused delay in flowering time for male and female inflorescence, accelerated leaf senescence, reduced total dry matter production, N-uptake by plants, grain yield components and grain protein percentage. On the other hand, nitrogen use efficiency for dry matter and grain production and nitrogen harvest index were increased under limited soil N. Inbred lines showed severe reduction for the above variables as compared to crosses. The inbred lines 4, 9, 13 and 15 were distinguished for their superiority in grain yield, nitrogen harvest index, harvest index, nitrogen use efficiency for grain, N-uptake and protein percentage. Three lines, 13, 15 and 16 were the earliest in flowering and represented the highest stay green percentage. While, the inbred lines 1, 8 and 14 were the most N-inefficient for grain production and the lowest for grain yield. In relation to crosses, high nitrogen harvest index, harvest index and nitrogen use efficiency for grain were shown by the crosses (4x1), (8x7), (9x10), (9x12) and (13x15). The crosses (4x1), (9x10), (13x15) and (13x16) surpassed the check and recorded the highest grain yield. The highest stay green percentage was revealed by the single cross Pioneer 3062 followed by the crosses (4x1), (13x15) and (13x16). It is recommended to use the inbred lines; 4, 9, 13 and 15, as a N-efficient source for further studies, whereas using the crosses; (4x1), (8x7), (9x10), (9x12) and (13x15) as N-efficient hybrids for under N limited cultivation. Phenotypic correlation coefficients were higher at low N compared with high application rate. High grain yield was significantly associated with delayed leaf senescence, nitrogen harvest index, harvest index, nitrogen use efficiency for grain and yield plant-1. High nitrogen use efficiency for grain production correlated positively with high yield, yield plant-1, NHI and HI. N-uptake was found to be a function of growth rate at both levels of N fertilizer.
The objective of this study was to estimate the general combining ability of the parents and specific combining ability of hybrids for earliness traits for line selection. Inheritance and interrelationships of earliness characters were evaluated in a line x tester design. Three intermediate-early-maturing female (lines) which are grown regionally and four early-maturing males (testers) cotton varieties were crossed in 2003. The twelve F(1) and seven parents were planted randomized block design with three replications in 2004. For each earliness trait, general combining ability (GCA) and specific combining ability and gene effects were estimated using the line x tester method of analysis and also were determined heterosis and narrow sense heritability. Parents and their hybrids (except the monopodial branch) were significant for all the earliness traits studied. Estimates of variance due to GCA and SCA and their ratio revealed predominantly non-additive gene effects for date of first square, date of first flowers and harvested rate of first picking. Among the lines, Ersan 92 and Maras 92 and among the testers Acala Royal was found to be the best general combiners for most of the earliness characters. Four out of twelve crosses namely Ersan 92 x Chirpan 603, Ersan 92 x Acala Maxa, Maras 92 x Acala Royal and Nazilli 87 x Acala Royal were found to be the best crosses for investigated earliness characters.
A half diallel cross between 7 inbred lines of maize was evaluated under two different nitrogen rates for six quantitative characters. Nitrogen rates, genotypes, parents, hybrids and parents vs crosses mean squares were significant for all traits. Significant genotypexnitrogen rate mean squares were obtained for days to 50% maturity, No. of rows ear-1 and shelling%. Significant interaction mean squares between hybridsXnitrogen rates were detected for days to 50% maturity, No. of rows ear-1 and grain yield plant"1. General and Specific Combing Ability (GCA and SCA) mean squares were significant for all traits. GCA/SCA ratios revealed that the additive and additivexadditive types of gene action were the most important expressions for days to 50% maturity, number of rows ear-1 and shelling% in both and nitrogen rates and combined analysis. Significant interaction mean squares between nitrogen rates and GCA and SCA were detected for most traits. The crosses P1XP2 and P1XP7 at the low nitrogen level, P1×P4, P1×P6, P1×P7 and P2×P5 hybrids at the normal nitrogen level and the hybrid P1×P7 in the across nitrogen levels, were out yielded the check hybrid (Pioneer 30K8). Also, single cross P1×P7did not differ significantly from the hybrid Hytech 2031 in low nitrogen rate and combined analysis for grain yield plant"1. The parental inbred line No. 4 gave a good combiner for No. of rows ear-1 and grain yield plant-1 at both and across nitrogen rate. The most desirable inter and intra allelic interactions were presented by combinations: P1×P6, P1×P7, P2×P6 and P5×P6 for 100-kernel weight, P1×P2, P1×P4, P1×P6, P1×P7, P2×P3, P2×P5, P2×P7 and P4×P7 for gram yield plant-1 and P1×P4 and P4×P7 for shelhng%. These crosses may be prime importance in breeding programs either towards hybrid maize production or synthetic varieties composed of hybrids which involved the good combiners for the traits in view.
An official journal of the Genetics Society, Heredity publishes high-quality articles describing original research and theoretical insights in all areas of genetics. Research papers are complimented by News & Commentary articles and reviews, keeping researchers and students abreast of hot topics in the field.
In this study the effect of nitrogen and phosphorus application on growth, forage yield and quality of fodder maize was studied. The variety used was Giza 2. Nitrogen was applied at the rates of (0, 40 and 80 kg N ha-1), while phosphorus levels were (0, 50 and 100 kg P2O5 ha-1). Parameters studied were plant height, number of leaves per plant, stem diameter and Leaf Area Index (LAI). Moreover days to 50% tasseling, dry matter yield, crude protein and crude fiber contents were studied. Results showed that addition of nitrogen fertilizer significantly increased plant height, stem diameter and LAI. Phosphorus fertilization has no significant effect on the growth attributes. Application of nitrogen allowed the crop to reach 50% tasseling earlier. Phosphorus on the other hand has no effect on days to 50% tasseling. Nitrogen fertilization significantly increased the forage dry matter yield. In contrast phosphorus has no effect on the dry matter yield. Nitrogen was significantly increased the protein content of forage maize, on the other hand phosphorus has no effect on the crude protein content. Neither nitrogen nor phosphorus has a significant effect on the crude fiber content.
The present study was undertaken to characterize the genetic architecture of various local and CIMMYT inbred line crosses using LinexTester design. The material was generated at Winter Maize Nursery, Amberpet, Hyderabad 2004-2005. The parental lines (15), testers (3) and test crosses (45) were evaluated at two diverse locations of Kashmir valley namely Larnoo and Wadura during 2005. The analysis of variance revealed significant mean squares due to progenies, crosses and parents v/s crosses for all traits. GxE interaction was significant for all traits except ear diameter and 100-seed weight. The analysis for combining ability revealed significant variances due to GCA and SCA for all traits with preponderance of latter. Correspondingly the estimates of genetic components of variance also revealed predominance of non-additive component. The present study identified various parents and crosses in terms of per se performance and GCA and SCA estimates. The implications on maize breeding in light of results of present study have been discussed.
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