scholarly journals Heterotic Patterns of Temperate and Tropical Maize by Ear Photometry

2021 ◽  
Vol 12 ◽  
Author(s):  
Seth A. Tolley ◽  
Amritpal Singh ◽  
Mitchell R. Tuinstra
Keyword(s):  
Yield Components ◽  
Inbred Lines ◽  
Kernel Weight ◽  
Heterotic Group ◽  
Kernel Size ◽  
Heterotic Groups ◽  
Breeding Programs ◽  
Testcross Performance ◽  
Drought Tolerant ◽  
Variety Protection

As the plant variety protection (PVP) of commercial inbred lines expire, public breeding programs gain a wealth of genetic materials that have undergone many years of intense selection; however, the value of these inbred lines is only fully realized when they have been well characterized and are used in hybrid combinations. Additionally, while yield is the primary trait by which hybrids are evaluated, new phenotyping technologies, such as ear photometry (EP), may provide an assessment of yield components that can be scaled to breeding programs. The objective of this experiment was to use EP to describe the testcross performance of inbred lines from temperate and tropical origins. We evaluated the performance of 298 public and ex-PVP inbred lines and 274 Drought Tolerant Maize for Africa (DTMA) inbred lines when crossed to Iodent (PHP02) and/or Stiff Stalk (2FACC) testers for 25 yield-related traits. Kernel weight, kernels per ear, and grain yield predicted by EP were correlated with their reference traits with r = 0.49, r = 0.88, and r = 0.75, respectively. The testcross performance of each maize inbred line was tester dependent. When lines were crossed to a tester within the heterotic group, many yield components related to ear size and kernels per ear were significantly reduced, but kernel size was rarely impacted. Thus, the effect of heterosis was more noticeable on traits that increased kernels per ear rather than kernel size. Hybrids of DTMA inbred lines crossed to PHP02 exhibited phenotypes similar to testcrosses of Stiff Stalk and Non-Stiff Stalk heterotic groups for yield due to significant increases in kernel size to compensate for a reduction in kernels per ear. Kernels per ear and ear length were correlated (r = 0.89 and r = 0.84, respectively) with and more heritable than yield, suggesting these traits could be useful for inbred selection.

scholarly journals Combining ability and testcross performance of drought-tolerant maize inbred lines under stress and non-stress environments in Kenya

2017 ◽  
Vol 136 (2) ◽  
pp. 197-205 ◽  
Author(s):  
Berhanu T. Ertiro ◽  
Yoseph Beyene ◽  
Biswanath Das ◽  
Stephen Mugo ◽  
Michael Olsen ◽  
...  
Keyword(s):  
Combining Ability ◽  
Inbred Lines ◽  
Testcross Performance ◽  
Drought Tolerant ◽  
Maize Inbred Lines ◽  
Stress Environments

scholarly journals Genetic diversity among tropical maize inbred lines as revealed by SSR markers

2020 ◽  
pp. 2010-2019
Author(s):  
Maizura Abu Sin ◽  
Ghizan Saleh ◽  
Nur Ashikin Psyquay Abdullah ◽  
Pedram Kashiani
Keyword(s):  
Genetic Diversity ◽  
Ssr Markers ◽  
Gene Diversity ◽  
Polymorphic Information Content ◽  
Similarity Index ◽  
Inbred Lines ◽  
Hybrid Breeding ◽  
Heterotic Groups ◽  
Breeding Programs ◽  
Maize Inbred Lines

Genetic diversity and phenotypic superiority are important attributes of parental inbred lines for use in hybrid breeding programs. In this study, genetic diversity among 30 maize (Zea mays L.) inbred lines comprising of 28 introductions from the International Maize and Wheat Improvement Center (CIMMYT), one from Indonesia and a locally developed, were evaluated using 100 simple sequence repeat (SSR) markers, as early screening for potential parents of hybrid varieties. All markers were polymorphic, with a total of 550 unique alleles detected on the 100 loci from the 30 inbred lines. Allelic richness ranged from 2 to 13 per locus, with an average of 5.50 alleles (na). Number of effective alleles (ne) was 3.75 per locus, indicating their high effectiveness in revealing diversity among inbred lines. Average polymorphic information content (PIC) was 0.624, with values ranging from 0.178 to 0.874, indicating high informativeness of the markers. High gene diversity was observed on Chromosomes 8 and 4, with high number of effective alleles, indicating their potential usefulness for QTL analysis. The UPGMA dendrogram constructed identified four heterotic groups within a similarity index of 0.350, indicating that these markers were able to group the inbred lines. The three-dimensional PCoA plot also supports the dendrogram grouping, indicating that these two methods complement each other. Inbred lines in different heterotic groups have originated from different backgrounds and population sources. Information on genetic diversity among the maize inbred lines are useful in developing strategies exploiting heterosis in breeding programs

Microsatellite marker-based genetic diversity of tropical-adapted shrunken-2 maize inbred lines and its relationship with normal endosperm inbred lines of known heterotic classification

2021 ◽  
pp. 1-8
Author(s):  
J. E. Iboyi ◽  
A. Abe ◽  
V. O. Adetimirin
Keyword(s):  
Genetic Diversity ◽  
Gene Diversity ◽  
Polymorphic Information Content ◽  
Inbred Lines ◽  
Heterotic Group ◽  
Germplasm Management ◽  
Maize Breeding ◽  
Heterotic Groups ◽  
Maize Population ◽  
Maize Inbred Lines

Abstract Knowledge of the genetic diversity and relationships among maize inbred lines can facilitate germplasm management and plant breeding programmes. The study investigated the level of genetic diversity among S6 lines developed from a tropical-adapted shrunken-2 (sh-2) maize population and their relationship with normal endosperm tropical inbred lines of known heterotic groups. Ninety-one sh-2 maize inbred lines (UI1-UI91) developed in the University of Ibadan super-sweet Maize Breeding Programme were genotyped at 30 simple sequence repeat (SSR) loci, alongside five normal endosperm maize inbred lines viz. TZi3, TZi4, TZi10, TZi12 and TZi15, four of which belong to two heterotic groups. Twenty-three SSR markers were polymorphic and detected a total of 61 alleles, with a range of 2–7 and an average of 2.65 alleles per locus. The polymorphic information content ranged from 0.12 in bnlg1937 to 0.77 in phi126, with an average of 0.36. The gene diversity (He) averaged 0.43. Cluster analysis resulted in five groups consisting of 16, 36, 17, 23 and 3 inbred lines, with one sh-2 line ungrouped. TZi 12 and TZi 15, both of which are of the same heterotic group, clustered with TZi 3 of another heterotic group. Considerable genetic diversity exists among the 96 inbred lines. Only two of the five normal endosperm lines shared clusters with the sh-2 lines. The clustering of the normal endosperm inbred lines is not related to their established heterotic patterns. Inbred lines in two clusters offer the possibility of guiding the exploitation of heterosis among the sh-2 lines.

scholarly journals Seleksi Jagung Inbrida dengan Marka Molekuler dan Toleransinya terhadap Kekeringan dan Nitrogen Rendah

2015 ◽  
Vol 34 (1) ◽  
pp. 43
Author(s):  
Roy Efendi ◽  
Yunus Musa ◽  
M. Farid Bdr ◽  
M. Danial Rahim ◽  
M. Azrai ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Drought Stress ◽  
Inbred Lines ◽  
Heterotic Group ◽  
Heterotic Groups ◽  
Maize Varieties ◽  
Group A ◽  
Selection For ◽  
N Fertility ◽  
Water Treatments

<p>Information on genetic diversity, homozygosity, drought stress and low N tolerance of maize inbred line are useful for parental selection in developing maize varieties tolerant to drought and low N. The objectives of this study were (a) selection for homozygoes lines and analysis of genetic diversity among 51 maize inbred lines applying simple sequence repeats (SSRs) using thirty six markers (b) selection for inbred lines (homozygosity over 80%) for drought and low nitrogen (N) tolerance. Experiment was conducted using split-split plots design with three replications. Water treatments were as the main plots (well-watered and drought stress conditions), subplots were nitrogen fertilization at rate of 75 and 150 kg N/ha and the sub-sub plots were 51 inbred lines. The results showed that there were broad ranges of genetic variability among inbred lines with genetic similarity coefficient values ranging from 0.22 to 0.87 and polymorphism information content average was 0.57. Thirty inbreds having homozygosity over 80% were spread into six heterotic groups. Drought tolerance inbreds were in heterotic groups C and F, namely DTPYC9-F46-3-9-1-1-B and 1044-30, the drought medium tolerance in heterotic group A and B, namely CML 161/NEI 9008 and MR 14. Inbred for low-N fertility tolerance was in the heterotic group D namely G20133077, while medium tolerance to low-N fertility inbreds were in heterotic group A, B, C, D, and F, and they were CML 161/NEI 9008, CY 11, CY 15, CY 6, CLRCY039, Nei9008, DTPYC9-F46-1-2-1-2-B, G2013627, G2013649, 1044-30. Inbreds tolerance to both medium drought and to low-N fertility were in heterotic group C and F they were DTPYC9-F46-1-2-1-2-B and 1044-30. Inbred lines of maize tolerant to drought and to low-N fertility can be used as parent to develop hybrid or synthetic varieties, posessing stress tolerances, by cross recombination between heterotic groups.</p>

scholarly journals Genetic diversity and population structure of early and extra-early maturing maize germplasm adapted to sub-Saharan Africa

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Baffour Badu-Apraku ◽  
Ana Luísa Garcia-Oliveira ◽  
César Daniel Petroli ◽  
Sarah Hearne ◽  
Samuel Adeyemi Adewale ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Inbred Lines ◽  
Snp Markers ◽  
Rapid Expansion ◽  
Sub Saharan Africa ◽  
Heterotic Groups ◽  
Breeding Programs ◽  
Early Maturing ◽  
Sub Saharan

Abstract Background Assessment and effective utilization of genetic diversity in breeding programs is crucial for sustainable genetic improvement and rapid adaptation to changing breeding objectives. During the past two decades, the commercialization of the early and extra-early maturing cultivars has contributed to rapid expansion of maize into different agro-ecologies of sub-Saharan Africa (SSA) where maize has become an important component of the agricultural economy and played a vital role in food and nutritional security. The present study aimed at understanding the population structure and genetic variability among 439 early and extra-early maize inbred lines developed from three narrow-based and twenty-seven broad-based populations by the International Iinstitute of Tropical Agriculture Maize Improvement Program (IITA-MIP). These inbreds were genotyped using 9642 DArTseq-based single nucleotide polymorphism (SNP) markers distributed uniformly throughout the maize genome. Results About 40.8% SNP markers were found highly informative and exhibited polymorphic information content (PIC) greater than 0.25. The minor allele frequency and PIC ranged from 0.015 to 0.500 and 0.029 to 0.375, respectively. The STRUCTURE, neighbour-joining phylogenetic tree and principal coordinate analysis (PCoA) grouped the inbred lines into four major classes generally consistent with the selection history, ancestry and kernel colour of the inbreds but indicated a complex pattern of the genetic structure. The pattern of grouping of the lines based on the STRUCTURE analysis was in concordance with the results of the PCoA and suggested greater number of sub-populations (K = 10). Generally, the classification of the inbred lines into heterotic groups based on SNP markers was reasonably reliable and in agreement with defined heterotic groups of previously identified testers based on combining ability studies. Conclusions Complete understanding of potential heterotic groups would be difficult to portray by depending solely on molecular markers. Therefore, planned crosses involving representative testers from opposing heterotic groups would be required to refine the existing heterotic groups. It is anticipated that the present set of inbreds could contribute new beneficial alleles for population improvement, development of hybrids and lines with potential to strengthen future breeding programs. Results of this study would help breeders in formulating breeding strategies for genetic enhancement and sustainable maize production in SSA.

scholarly journals Genotype dependent tolerance to herbicides of maize (Zea mays L.) inbred lines

Genetika ◽  
2015 ◽  
Vol 47 (1) ◽  
pp. 97-106 ◽  
Author(s):  
Milan Brankov ◽  
Milena Simic ◽  
Vesna Dragicevic ◽  
Sava Vrbnicanin ◽  
Igor Spasojevic
Keyword(s):  
Secondary Metabolites ◽  
Grain Yield ◽  
Herbicide Tolerance ◽  
Inorganic Phosphorus ◽  
Inbred Lines ◽  
Sulfhydryl Groups ◽  
Heterotic Group ◽  
Heterotic Groups ◽  
Protein Sulfhydryl ◽  
Protein Sulfhydryl Groups

Herbicide application in seed maize requires special attention due to their larger sensitivity than hybrid maize. The aim of study was to examine and define the sensitivity/tolerance of the five maize inbred lines with different susceptibility to herbicides (belonging to different heterotic groups), based on alterations of secondary metabolites (phenolics, protein sulfhydryl groups, phytic and inorganic phosphorus). Two groups of herbicides: triketons (mesotrione and topramezone) and sulfonylureas (rimsulfuron and foramsulfuron) were tested. Lines from independent heterotic group, which were sensitive to herbicides expressed visible damages together with significant reduce in grain yield, mainly induced by sulfonylurea herbicides. Parallel with that, significant increase in phenolics, phytic and inorganic phosphorus, as well as drop in protein sulfhydryl groups were observed in their leaves. Tolerant lines (belonging to Lancaster group) had mainly insignificant grain yield reduce, also with lesser variations in sulfhydryl groups, content of phytic and inorganic phosphorus, as well as increase in phenolics content. Among examined secondary metabolites, phytate is the main factor, contributing to herbicide tolerance in maize lines. Owing to lesser yield decrease and variation in content of examined secondary metabolites, expressed in treatments with triketone herbicides, they usage could be safe in maize lines.

Yield and yield component response of barley in subarctic and temperate environments

1992 ◽  
Vol 72 (3) ◽  
pp. 663-669 ◽  
Author(s):  
S. M. Dofing ◽  
C. W. Knight ◽  
T. G. Berke ◽  
P. S. Baenziger
Keyword(s):  
Hordeum Vulgare ◽  
Yield Components ◽  
Poor Performance ◽  
Kernel Weight ◽  
Yield Component ◽  
Hordeum Vulgare L ◽  
Breeding Programs ◽  
Barley Cultivars ◽  
The Poor ◽  
Superior Genotypes

Plant breeders are continually searching for new sources of genetically diverse germplasm from which superior genotypes might be developed. The objective of this study was to assess the performance of subarctic- and temperate-adapted barley cultivars when grown in reciprocal areas of adaptation to determine their potential for use in breeding programs. Four subarctic-adapted and four temperature-adapted barley (Hordeum vulgare L.) cultivars were grown at two environments each in Alaska (subarctic) and Nebraska (temperate) for 2 yr. Subarctic-adapted cultivars were earlier heading and earlier maturing in both environments, although differences were larger in subarctic environments. Grain yield of the two classes of cultivars was similar in subarctic environments, but temperate-adapted cultivars were far superior when grown intemperate environments. Kernel weight of all cultivars was higher in subarctic environments than in temperate environments. Maturity differences alone did not account for the poor performance of subarctic-adapted cultivars in temperate environments. Yield was positively correlated with all three yield components in temperate environments, but only with spikes per square meter in subarctic environments. Results from this study suggest that greater potential exists for the utilization of temperate-adapted germplasm to favourably increase the genetic diversity of subarctic-adapted germplasm than vice versa.Key words: Barley, Hordeum vulgare L., adaptation, yield components

scholarly journals Phenotypic characterization and relatedness of maize inbred lines

Genetika ◽  
2008 ◽  
Vol 40 (3) ◽  
pp. 227-236 ◽  
Author(s):  
Vojka Babic ◽  
Milosav Babic ◽  
Milomir Filipovic ◽  
Nenad Delic ◽  
Violeta Andjelkovic
Keyword(s):  
Cluster Analysis ◽  
Visual Assessment ◽  
Inbred Lines ◽  
Phenotypic Characterization ◽  
Materials Testing ◽  
Pedigree Data ◽  
Genetic Origin ◽  
Heterotic Groups ◽  
Variety Protection ◽  
Large Clusters

Clear description of maze is useful in planning crosses for hybrids, in classifying inbreds to heterotic groups, and in the plant variety protection. The objection to visual assessment of morphological traits is its subjectivity. But it can be very useful for plant breeders especially when they work with a material of unknown genetic origin. The phenotypic characterization (30 traits) of 45 inbred lines according to the UPOV Descriptor, with a known pedigree, is used with the main goal to investigate a possibility of exploiting such a kind of information for the classification of inbred lines in homogenous groups according to their relatedness. Ward's method of cluster analysis had the best concordance with pedigree data. This method divided 45 inbreds into two large clusters, each of them containing two subclusters. Quality of the cluster analysis with four groups was tested by the discrimination analysis. All of the tree discrimination functions were significant and enclosed 64%, 20% and 16% of variance, respectively. In plant breeding such information can be useful for a more precise description of existing heterotic groups, as well as, for grouping lines of unknown genetic origin. On the basis of obtained grouping, the decision on their crossing can be made. Hence they either should be crossed to related (F2 populations for a new selection) or unrelated materials (testing of combining abilities).

scholarly journals Determinación del patrón heterótico de 30 líneas de maíz derivadas de la población 43SR del CIMMYT.

2016 ◽  
Vol 8 (1) ◽  
pp. 26 ◽  
Author(s):  
Arturo Terron ◽  
Ernesto Preciado ◽  
Hugo Córdova ◽  
Raymundo López
Keyword(s):  
Grain Yield ◽  
Inbred Lines ◽  
Heterotic Group ◽  
Average Yield ◽  
Subtropical Region ◽  
Selected Lines ◽  
Heterotic Groups ◽  
Combined Analysis ◽  
Group A ◽  
Group B

Observed 30 selected lines were crossed to two testers: CML-320 (heterotic group “A”) and CML- 321 (heterotic group “B”). The 60 line x tester combinations were evaluated at four location in the subtropical region of Mexico. In the combined analysis across locations the variance componentsfor the GCA and SCA were significant for grain yield. Significant SCA values allowed the separation of the inbred lines into two opposite heterotic groups based on the performance of the test crosses. On the basis of this information, two synthetics were formed with 7 inbred lines each defined as heterotic groups “A” and “B”. Nine single crosses outyielded the commercial check hybrid. Across locations the top yielder hybrid produced 9.48 t/ha which was 15.6% higher than the check. Average yield by location was 7.1, 3.8, 11.1 and 9.0 t/ha at Tlaltizapán, Tlajomulco, Celaya y Pabellón, respectively. Positive and significant GCA values were observed in six inbred lines. The GCA effects ranged from 1.18 to -2.19. The inbred lines from this study can effectively be used in hybridization programs.

scholarly journals The Usefulness of Molecular Markers Approach for Developing Heterotic Groups in Maize

2014 ◽  
Vol 1 (2) ◽  
pp. 4-10
Author(s):  
Willy B Suwarno
Keyword(s):  
Molecular Markers ◽  
Genetic Distance ◽  
Genetic Background ◽  
Inbred Lines ◽  
Genetic Distances ◽  
Heterotic Group ◽  
Maize Breeding ◽  
Heterotic Groups ◽  
Good Opportunity

The phenomenon of heterosis provides a greatopportunity for plant breeders to gain greaterperformance and yield in the hybrids compared to theirinbred line parents. In most cross-pollinated crops likemaize, heterosis plays an important role as theperformance of the hybrids is of a great value. Heterosisgain much interest until recently and current studies stillattempt to elucidateone of these is utilizing molecularmarkers to estimate genetic distances among inbredlines followed by developing putative groups. In a welldened heterotic group, between-groups mating areexpected to produce better hybrids than within-groupsmating. Some studies of marker-aided heterotic groupdevelopment resulted in functional heterotic groups;while some other reported that the groups failed toprovide evidence of heterosis in the hybrids.Considering the prediction of hybrids' performance willdepend on genetic background of inbred lines, andmarkers technology are continuously improved, there isstill a good opportunity to obtain useful heterotic groupsfor a particular breeding population.Keywords: maize breeding, genetic distance, heterosis,molecular markers.

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