Gene action, heterosis, correlation and regression estimates in developing hybrid cultivars in maize (original) (raw)
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Heterosis and combining ability for grain yield and its components in selected maize inbred lines
South African Journal of Plant and Soil, 2007
Information on heterosis and combining ability of adapted maize (Zea mays L.) inbred lines is essential to maximize their use for variety development. This study was conducted to determine heterosis and combining ability of selected inbred lines for yield and yield components. Eight inbred lines were crossed in a diallel mating system. The crosses and parents were evaluated in a randomised complete block design with three replications at Bako Research Center, Ethiopia, in 2001 and 2002. There were significant differences between the entries for measured traits. Mean mid-parent heterosis (MPH) ranged from 2.9% for days to maturity to 89.2% for grain yield and high-parent heterosis from 0.65% for ear diameter to 64% for grain yield. All crosses exhibited positive MPH for ear and plant height, ear length, kernels per row and grain yield. General and specific combining ability effects were significant for most traits. Gutto LMS 5 , CML-202 and CML-387 were good general combiners for ear and plant height, and days to maturity. Line 143-5-i was the best general combiner for grain yield. This study identified inbred lines and hybrid combinations that had desirable expression of important traits. This will be useful for the development of high yielding hybrids.
Correlations and genetic parameters in maize hybrids
Bioscience Journal, 2016
The study of the genetic control of agronomic traits and heritage through estimates of genetic parameters of a population allows inferences about its genetic variability and which can be expected of gain with selection. Know the correlations among traits of interest for selection allows to the breeder know the degree of association among traits of economic importance, given that the selection of certain trait changes the behavior of the other. With the aim to estimate genetic parameters and identify agronomic traits correlated with the grain yield of maize hybrids, an experiment was conducted at the State University of Mato Grosso do Sul-University Unit of Aquidauana (UEMS/UUA). The experimental design was a randomized block with four replications. Treatments consisted of 20 maize hybrids. The traits evaluated were: plant height, first ear height, stem diameter, ear diameter, ear length, number of rows per ear, number of kernels per row, hundred grain weight and grain yield. The hybrids XB9010, P30F53, 20A78HX, XB6012, P3340, AG9010 and XB7253, obtained the highest grain yield and mass of one hundred grains. The population has a genetic variability and potential for selection of all traits. Based on the evaluated genetic parameters, mass of hundred grains can be used at the direct selection of genotypes with high grain yield.
In Ghana: low yield of maize 1.7 t ha-1 has been reported. Thus, use inbred lines with good combining ability for yield and yield-contributing characters to form excellent combinations is crucial. Thus, the present study was designed to estimate the combining ability effects of tropical white maize inbred lines for yield and yield-contributing traits. A line x tester mating design involving sixteen white maize inbred lines as females and two testers as males generated thirty-two single crosses. These hybrids plus three checks were evaluated using a 5 x 7 alpha lattice design replicated twice at the University of Ghana, WACCI research farm during 2015/-16 offseason using drip irrigation. Analysis of variance revealed that genotype mean squares were highly significant (P < 0.001) for days to 50% an thesis and silking, plant and ear height, plant aspect, ear length, number of kernel rows ear-1 , number of kernels row-1 and yield. Similarly, mean squares of genotypes were significant (p < 0.05) for ear rots, an thesis-silking interval, husk cover and maize streak virus disease. Line x tester revealed both additive and non-additive gene action played important role in the inheritance of all the traits indicating that both progeny selection and heterosis breeding will be valuable for future breeding programme using these inbred lines. However, the ratio of general combining ability (GCA) variance to specific combining ability (SCA) variance was less than unity, indicating the prevalence of non-additive gene action in the inheritance of all the parameters studied except for days to 50% anthesis and anthesis-silking interval Three inbred lines L16 (867), L1 (595) and L8 (247) were identified to have high GCA effects for yield kg ha-1 , indicating that these lines have the genetic potential to transmit this desirable trait to their progenies. Based on the SCA effect for grain yield, the lines were separated into two heterotic groups. The lines L1, L3, L4, L8, L11 and L14 belonged to tester group 1368 while L2, L5, L6, L7, L9, L10, L12, L13, L15 and L16 belonged to heterotic group of CML 444. This is useful for the development of hybrids and synthetic varieties. The information generated in the present study will be useful for breeders who want to improve yield and yield-contributing traits of maize.
Heterotic groups and combining ability of yellow maize inbreds with three commercial hybrids
RESEARCH ON CROPS, 2018
maize inbreds along with three commercial hybrids in Indonesia. Six inbred lines and two testers were crossed and evaluated for grain yield and heritability of agronomic characters. Randomized complete block design was used as an experimental design with three replications at each location. The hybrids and three commercial checks were evaluated across three locations in Indonesia (Bone/South Sulawesi, Mataram/West Nusa Tenggara and Probolinggo/East Java Province, Indonesia). The results of variance analysis showed that interaction mean squares of test crosses × locations exhibited significant results for grain yield (1.29**). Mean performance of test crosses for grain yield indicated that three test crosses viz., L3 x T2 (10.97 t/ha), L5 x T2 (10.39 t/ha) and L6 x T2 (10.27 t/ha) showed significantly higher yield over the best check DK 979 (9.80 t/ha), while hybrid L4 x T1 was the least performing in grain yield (8.44 t/ha). Based on the sca effect for grain yield, the inbred lines were clustered into two different groups. Inbred lines under heterotic group A were inbreds CLYN 10 (L3), CLYN 15 (L5) and CLYN 16 (L6), while CLYN 2 (L1), CLYN 7 (L2) and CLYN 12 (L4) were under heterotic group B. This information is useful for the development of superior hybrid in Indonesia.
East African Journal of Sciences, 2020
Determination of heterosis in maize hybrids is necessary for identification of superior F1 hybrids for breeding programs. Therefore, this study was conducted to estimate the amount of standard heterosis for grain yield and related traits in order to identify potential hybrid for future breeding schemes. Eight maize inbred lines were mated through a half diallel mating design (Griffing's Method IV, Model I). The resulting twenty-eight F1 hybrids along with two standard checks (BHQPY 545 and MH 138) were evaluated using Alpha-Lattice Design with three replications during 2017/18 main cropping season at Haramaya University Research Site (Raare). Analysis of variance revealed significant variations for all traits indicating the existence of genetic variability. The result of heterosis estimation showed considerable amount of positive and negative heterosis for all traits studied. The highest percentage of standard heterosis for grain yield was manifested by the cross combinations L3 × L6 over BHQPY 545, and L3 × L6, L3 × L8, L2 × L5, L6 × L8, L1 × L4, L4 × L6 and L3×L4 over MH138 (greater than 20% yield advantage). The maximum positive and significant standard heterosis was recorded for L3 × L6, and L1 × L4 for 1000 kernel weight and number of kernels per row, respectively over the two checks BHQPY-545 and MH-138. The observed highest heterosis for grain yield and related traits indicated the possibility of increasing yield by exploiting heterotic potential of maize genotypes. The information generated by this study could be useful for researchers who need to develop high yielding maize hybrids. Hence the potential hybrids could be recommended for commercial use, after verifying the results by repeating the research over years and across locations.
Estimation of heterosis in yield and yield attributing traits in single cross hybrids of maize
Journal of Maize Research and Development, 2016
A field experiment was conducted at National Maize Research Program, Rampur, Chitwan, Nepal during winter season from 6 th October, 2015 to 5 th March 2016 to estimate different heterosis on single cross maize hybrids. Thirteen maize hybrids were tested randomized complete block design with three replications. Hybrid namely RML-98/RL-105 gave the highest standard heterosis (57.5%) for grain yield over CP-666 followed by RML-4/NML-2 (32.6%), RML-95/RL-105 (29%) and RML-5/RL-105 (20.6%). The hybrid RML-98/RL-105 produced the highest standard heterosis (75.1%) for grain yield over Rajkumar followed by RML-4/NML-2(50.2%), RML-95/RL-105(46.6%), RML-5/RL-105 and (35.7%). Mid and better parent heterosis were significantly higher for yield and yield attributes viz. ear length, ear diameter, no of kernel row per ear, no of kernel per row and test weight. The highest positive mid-parent heterosis for grain yield was found in RML-98/RL-105 followed by RML-5/RL-105, RML-95/RL-105, and RML-4/NML-2. For the grain yield the better parent heterosis was the highest in RML-98/RL-105, followed by RML-5/RL-105, RML-95/RL-105, and RML-4/NML-2. These results suggested that maize production can be maximized by cultivating hybrids namely RML-98/RL-105, RML-5/RL-105, RML-95/RL-105, and RML-4/NML-2 .
Genetic divergence among maize hybrids and correlations with heterosis and combining ability
Acta Scientiarum. Agronomy, 2012
Twelve corn hybrids recommended for cropping in the south-central region of the Paraná State and 66 crossings obtained among these hybrids were evaluated for agronomic and morphological traits. These genotypes were evaluated in three experiments performed in Laranjeiras do Sul, Guarapuava and Cantagalo, Paraná State, Brazil. Heterosis and specific combining ability (SCA) were estimated for yield of husked ears. Data from measuring 22 morphological/agronomical traits of the parents were subjected to a multivariate joint analysis of variance and cluster analysis to group the parental hybrids via the neighbor method, using the generalized Mahalanobis distance. Pearson correlation coefficients between heterosis, SCA, D 2 and yield of husked ears were obtained. The cross P30F44 x Sprint displayed a high mean and a high heterosis for yield of husked ears, but a moderate estimate of genetic divergence. Estimates of genetic divergence were not effective at predicting the most heterotic crossings, as Pearson correlation coefficients between D 2 and heterosis and D 2 and CEC were not significant. Positive significant correlations were observed between yield means and CEC and heterosis.
Genetic Variability and Correlation Studies of Grain Yield and Related Agronomic Traits in Maize
A total of fourty two maize hybrids produced through a full diallel mating design and seven parental inbred lines were evaluated in three sites located at different agro-ecological zones in Kenya to determine the genetic parameters governing the inheritance of grain yield and related agronomical traits. The genetic parameters studied among the traits included the mean performance, genotypic variances, phenotypic variances, genotype by environment variances, broad sense heritability and phenotypic and genotypic correlation coefficients. Significant differences were recorded for all traits studied thereby revealing the diversity of the maize genotypes. The grain yield and days to maturity which showed high heritability had low genotypic variances suggesting the involvement of non-additive gene action which could be utilized through heterosis breeding. Ear height and plant height showed the highest heritability and high genotypic variances suggesting the preponderance of additive gene action. Grain yield was positively and strongly correlated with ear height and plant height. The tall plants with high ear placement gave better yields and this could be attributed to the high dry matter accumulation function carried out by the high number of leaves possessed. The positive relationships observed in this study imply that the desirable traits in these hybrids could be exploited in further breeding activities for the development of composites and synthetics for the resource constrained maize farmers who cannot access hybrid seeds every year.
2020
Quick Response Code Abstract: Combining ability of inbred lines is important information in maize(Zea mays.L) hybrid breeding programs to incorporate genotypes from various germplasm sources. This study was conducted with germplasm developed using double haploid technology (DH) lines. Sixty-six F1 crosses resulted from diallel crosses of 12 maize inbred lines with four standard checksArgane (AMH800), Kolba (AMH853), Jibat (AMH851) and Wenchi (AMH850) were evaluated based on partial diallel meeting fashion and its relative analysis to estimate general combining ability (GCA) and specific combining ability (SCA) for yield and yield related traits using alpha-lattice design with three replications during the 2017 cropping season at Ambo, Holeta and Kulumsa Agricultural research center of Ethiopian Institution of agricultural Reseach Institution. Analysis of variance showed that mean squares due to entries were significant for most of the traits studied, such as grain yield, thousand ke...
Information on the combining ability and heterotic pattern of elite inbred lines is essential to maximize their use in hybrid maize development. This study was conducted to determine combining ability and heterotic pattern of locally developed maize inbred lines for grain yield and related traits. Seventeen inbred lines (10 female inbred lines and 7 tester inbred lines) were used to generate 70 single cross hybrids using line by tester crossing scheme. The resulting 70 cross progenies plus two standard checks arranged in 8×9 alpha lattice design replicated twice were planted at three mid-altitude sub-humid testing sites in Ethiopia (Bako, Hawassa and Pawe) in 2011 main cropping season. The combined analysis of variance for yield and other related traits showed highly significant differences among genotypes, crosses, female inbred lines (General combining ability, GCA), tester inbred lines (GCA), line x tester (Specific combining ability, SCA); and the interactions of these source of variation with the environment for all traits studied except for ear aspect (EA) and grain yield (GY) in female inbred lines (GCA), EA in inbred line testers (GCA) and for days to anthesis (AD) in line x tester (SCA) x environment. The significance of both GCA (lines and testers) and SCA of LxT for AD, days to silking (DS), plant height (PH), ear height (EH), EA and GY showed that both additive and non-additive gene actions are important in controlling these traits. Furthermore, the proportion of GCA sum of squares were greater than the SCA sum of squares for AD, DS, PH, EH, and EA indicating the predominance of additive gene actions in controlling these traits. For GY, the ratio of GCA to SCA sum of squares was near to unity indicating both additive and non-additive gene actions were equally important. This study identified inbred lines that can make good cross combination for more than one trait. L1 was found to be good combiner for lower values of AD, DS, PH and EH indicating that this line could be used in improving maize for earliness and short stature. L4 was ideal parent for reducing AD and DS. L3 was found to be good combiner for GY and other related traits. In addition, lines were grouped into heterotic group A, B or AB based on SCA. Based on its per se performance and combining ability, L3 was proposed to be used as a tester in heterotic group B. This study also validated T5 remain to be used as a tester in heterotic group A. Based on the SCA of crosses, heterosis and per se performance of the parents, five best cross combinations were identified for possible release or for use as parents of three way hybrids. Further verification of the stability of the selected hybrids and the new proposed tester across more locations needs to be done.