Assessment of genetic diversity in maize inbred lines using RAPD markers

RAPD molecular markers were used to analyze genetic diversity between 16 corn lines. Twenty-two primerswere used resulting in the amplification of 265 fragments, of which 237 (84.44%) were polymorphic. Using the UPGMAmethod the genetic associations obtained showed 5 distinct heterotic groups. A principal coordinates analysis also showed anassociation of lines in 5 groups, in agreement with the results observed in the dendrogram. A bootstrap procedure wasapplied to verify whether the amount of markers used was sufficient to ensure reliability of the results, the procedure showeda coefficient of variation of 8.3%, suggesting that the markers were sufficient to assess genetic diversity between the analyzedlines. The high rate of polymorphism between lines revealed by RAPD markers indicated that the method is efficient to analyzegenetic diversity in corn lines and that the genetic divergence can be used to establish consistent heterotic groups between cornlines

Assessment of Genetic Diversity and Adaptability of Inbred Lines and their F1- hybrids of Grain Maize (Zea mays L.), Using Molecular Markers (RAPD) and AMMI Analysis

This study was carried out to assess the genetic diversity and adaptability of seven inbred lines of grain maize (Zea mays L.) and their F1-hybrids, using molecular markers (RAPD) and Additive Main Effects and Multiplicative Interaction (AMMI), respectively. A field experiment was carried out during the winter and summer of 2009 and 2010 at two locations, Shambat and Elrawakeeb. A split-plot design with three replications was used to layout the experiment. The inbred lines and their F1-hybrids were field-evaluated for grain yield/ha under normal irrigation and water-stress conditions. The DNA molecular markers (RAPD) analysis showed that high level of polymorphism of 89.33 percent was detected among the genotypes, which were distinguished into four main groups (sub-clusters). The genetic distance among inbred lines ranged from 0.05 to 0.33. The inbred line 66y was the most distant line compared to other inbred lines; it represents a single group in the cluster. The inbred lines 66y and 160 had the greatest genetic distance of 0.31. AMMI analysis differentiated the genotypes (inbred lines and F1- hybrids), based on their interaction to different environments, into diversified adaptation pattern. The hybrid 160x66y showed the highest (4.1 tons/ha) grain yield (highest heterosis) and a moderate positive interaction (PCA score = 19.0), indicating its adaptability to favorable environments. Moreover, the hybrid 66y×3 showed considerable yield (2.4 ton/ha) and adaptation to water stress environments. These results revealed that crossing of the most genetically-distant inbred lines (e.g., hybrid 160x66y) gave the highest heterosis, which could be utilized for improvement of grain yield of maize. Also, it could be concluded that DNA markers were efficient in the assessment of genetic diversity to identify the most appropriate inbred lines of maize for development of hybrid varieties, and then avoiding crosses between genetically-related inbred lines. Also AMMI analysis was successful to quantify the interaction and adaptability of the tested genotypes to wide range of environments

Application of Microsatellites in Genetic Diversity Analysis and Heterotic Grouping of Sorghum and Maize

Sorghum and maize are major cereal crops worldwide and key food security crops in Sub-Saharan Africa. The difference in the mating systems, maize as predominantly a cross-fertilizer and sorghum as a self-fertilizer is reflected in differences in visible phenotypic and genotypic variations. The reproductive differences dictate the level of genetic variation present in the two crops. Conventionally, a heterotic group assignment is made based on phenotypic values estimated through combining ability and heterosis analyses. However, phenotypic evaluation methods have their limitation due to the influence of the environment and may not reflect the heterotic pattern of the lines accurately. Therefore, more effective and complementary methods have been proposed for heterotic grouping of candidate lines. Estimation of molecular-based genetic distance has proven to be a useful tool to describe existing heterotic groups, to identify new heterotic groups, and to assign inbreds into heterotic groups. Among the molecular markers, microsatellites markers have proved to be a powerful tool for analyzing genetic diversity and for classifying inbred lines into heterotic groups. Therefore, the aim of this chapter was to elucidate the use of microsatellite markers in genetic diversity analysis and heterotic grouping of sorghum and maize

Comparison of morphological and molecular genetic distances of maize inbreds

Babic M., V. Babic, S. Prodanovic, M. Filipovic, and V. Andelkovic (2012): Comparison of morphological and molecular genetic distances of maize inbreds - Genetika, Vol 44, No. 1, 119-128. Due to an unknown mechanism of genetic control and great environmental effects in the process of trait expression, morphological markers are often considered unreliable indicators of genetic relationships. Morphological characterisation of 19 maize inbreds was done according to the UPOV descriptor, while molecular characterisation was performed with RAPD markers. Based on the estimation of phenotypes according to the UPOV descriptor, the squared Euclidean distance was calculated and then, on the basis of this distance, a morphological similarity matrix was formed. Jaccard similarity coefficients were calculated on the basis of presence-absence of bands on gels in the RAPD analysis. When data were standardised, the comparison between morphological and genetic similarity of observed maize inbreds was done. The correlations varied from 0.47 (inbred L 217) to 0.76 (inbred L 86). The average value of correlations for all studied inbreds amounted to 0.64. Furthermore, the results of the cluster analysis for both markers, molecular and morphological, had high concordance with pedigree data. Environmental effects were decreased in morphological markers (according to the UPOV descriptor) by rescaling a measurement scale from a scale to an ordinal level of measurement and in such a way results of morphological markers approached results of molecular markers in the estimation of the genetic distance (GD) of maize inbred lines

Genetic characterization of early maturing maize hybrids (Zea mays L.) obtained by protein and RAPD markers

Knowledge of maize germplasm genetic diversity is important for planning breeding programmes, germplasm conservation per se etc. Genetic variability of maize hybrids grown in the fields is also very important because genetic uniformity implies risks of genetic vulnerability to stress factors and can cause great losts in yield. Early maturing maize hybrids are characterized by shorter vegetation period and they are grown in areas with shorter vegetation season. Because of different climatic conditions in these areas lines and hybrids are developed with different features in respect to drought resistance and disease resistance. The objective of our study was to characterize set of early maturing maize hybrids with protein and RAPD markers and to compare this clasification with their pedigree information. RAPD markers gave significantly higher rate of polymorphism than protein markers. Better corelation was found among pedigree information and protein markers

Primena genetičkih markera u kontroli kvaliteta semena i oplemenjivanju biljaka

Genetic markers have been used at Institute of Field and Vegetable Crops in Novi Sad for a number of years, both for seed quality control and for research purposes. The Laboratory for Seed Testing was the first in the former Yugoslavia to use the method of control of hybrid seed genetic purity based on enzymatic polymorphism. This paper presents the application of protein markers, isozymes, seed storage proteins and DNA markers for evaluation of seed and breeding materials of various agricultural crops in Serbia.Genetički markeri se dugi niz godina koriste u Institutu za ratarstvo i povrtarstvo u Novom Sadu u kontroli kvaliteta semena i u istraživačke svrhe. Laboratorija za ispitivanje semena je prva u bivšoj Jugoslaviji uvela metod kontrole genetičke čistoće semena zasnovan na polimorfizmu enzima. U radu je dat pregled primene proteinskih markera, izoenzima i rezervnih proteina semena, kao i DNK markera u oceni kvaliteta semena i materijala za oplemenjivanje različitih biljnih vrsta u Srbiji

Comparison of RAPD, RFLP, AFLP and SSR markers for diversity studies in tropical maize inbred lines

In order to compare their relative efficiencies as markers and to find the most suitable marker for maize diversity studies we evaluated 18 inbred tropical maize lines using a number of different loci as markers. The loci used were: 774 amplified fragment length polymorphisms (AFLPs); 262 random amplified polymorphic DNAs (RAPDs); 185 restriction fragment length polymorphisms (RFLPs); and 68 simple sequence repeats (SSR). For estimating genetic distance the AFLP and RFLP markers gave the most correlated results, with a correlation coefficient of r = 0.87. Bootstrap analysis were used to evaluate the number of loci for the markers and the coefficients of variation (CV) revealed a skewed distribution. The dominant markers (AFLP and RAPD) had small CV values indicating a skewed distribution while the codominant markers gave high CV values. The use of maximum values of genetic distance CVs within each sample size was efficient in determining the number of loci needed to obtain a maximum CV of 10%. The number of RFLP and AFLP loci used was enough to give CV values of below 5%, while the SSRs and RAPD loci gave higher CV values. Except for the RAPD markers, all the markers correlated genetic distance with single cross performance and heterosis which showed that they could be useful in predicting single cross performance and heterosis in intrapopulation crosses for broad-based populations. Our results indicate that AFLP seemed to be the best-suited molecular assay for fingerprinting and assessing genetic relationships among tropical maize inbred lines with high accuracy.579588Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Assessment of genetic diversity in Sudanese maize (Zea mays L.) genotypes using random amplified polymorphic DNA (RAPD) markers

The randomly amplified polymorphic DNA (RAPD) molecular markers were used to assess genetic diversity in 27 Sudanese maize genotypes. Ten primers were used, resulting in the amplification of 59 fragments, of which 53 (89.33) were polymorphic. The maximum number of fragment bands (10) were produced by the primer A-1 with 100% polymorphism, while the minimum numbers of fragments (3) were produced by the primer OPA-20. Using the unweighted pair group method with arithmetic averages (UPGMA) method, the genetic associations obtained showed three distinct heterotic groups. The high rate of polymorphism between genotypes revealed by RAPD markers indicated that the method is efficient to analyze genetic divergence and can be used to establish consistent heterotic groups between maize genotypes.Key words: Randomly amplified polymorphic DNA (RAPD) markers, DNA polymorphism, maize genetic diversity

The conventional and contemporary technologies in maize (Zea mays L) breeding at Maize Research Institut Zemun Polje

Broad genetic variability of starting biological material is crucial prerequisite for the successful breeding program. Maize Research Institute, owning Gene bank with more than 6,000 accessions consisted of the local and introduced collection, has the opportunity for the investigation both fundamental genetic processes, pre-breeding and breeding for commercial purposes. To search for new sources of maize drought tolerance Gene bank accessions were scored visually on stay-green phenotype and total appearance. More than 50 genotypes have been identified as a potential source for drought tolerance. Besides breeding on improved storage protein quality decreasing of phytate content in kernel is also under the consideration, because the most phosphorous is bound in phytate. In breeding program it is desirable to have genotypes with higher content of available phosphorous (P) not bound in phytate. Among 60 analyzed populations from Gene bank only one has been determined to have very low phytate content and will be used in maize breeding program on low phytate in kernel. Process of maize breeding, to get high yielding hybrids, begins by the genetic variability determination of starting breeding material, either populations or selected inbred lines. Genetic divergence of parental inbred lines is main step to get high heterotic effect in yield after crossing. Use of different molecular markers allowed cluster analysis by use of UPGMA methods and select high number of genotypes to be included in crossing process