علی غفاری آذر

Maize (Zea mays L.) is one of the most important food crops worldwide and is widely used as genetic research material for studying various traits. Identification of genetic loci controlling quantitative trait is an important subject in genetics and breeding programs. In the present study, 102 maize inbred lines was evaluated for agro-morphological traits (plant height, plant height until first ear, leaf length, leaf width, leaf surface, leaf area indexear number, chlorophyll content, grain weight per plant, cob’s dry weight, cob’s diameter in first part, cob’s diameter in middle part, cob’s length, plant dry weight, days to tassel emergence, days to first ear emergence, days to second ear emergence) in completely randomized design with six replications. In the molecular experiment, 8 retrotransposon-based molecular markers primers was used for preparing the molecular profile of lines. Eight IRAP and REMAP primer combinations amplified 40 gene loci. Thirty-eight out of 40 loci (95%) showed polymorphism. The PIC values in the studied lines ranged from 0.084 for Ac/Ds to 0.383 for Pangrangja marker. The Nei’s genetic distance between lines prepared from Mashhad and Kermanshah was 0.053, between lines from Karaj and Mashhad was 0.036 and between lines from Kermanshah and Karaj was 0.032. In the analysis of population structure based on molecular markers, 102 studied lines were grouped into two subpopulations (K = 2). In the association analysis of agro-morphological traits based on two GLM and MLM methods, 24 and 12 marker-trait relationships were identified, respectively. In this study, two commons markers; Heartbraker (480) in cob’s diameter in first part and cob’s length and UBC878 × Ruda in ear number and grain weight per plant were identified with both general linear and mixed linear models. This information can be used in selecting individuals during tobacco breeding programs and developing varieties with high yield and performance.

Since the production of maize hybrids needs to selection and crossing of desirable inbred lines, identification of lines with suitable genetic characteristics is one of the objectives of plant breeders. In this study, ISSR markers were used to assess genetic diversity in 100 inbred lines of maize. Sixteen primers amplified 81 loci, of which 78 (95.12 %) were polymorphic. The maximum and minimum number of polymorphic bands were produced by UBC825 (8 loci) and UBC811 (2 loci) primers, respectively. The polymorphic information content (PIC) ranged from 0.65 (UBC849) to 0.93 (443), with an average of 0.77. Cluster analysis based on Jaccard’s similarity coefficient and complete linkage algorithm categorized the studied lines into 3 main clusters. The analysis of molecular variance using ISSR data showed that 9% of the variation was explained by the variation among population and 91% by the variation within population. The results showed that the ISSR markers capable to display a high degree of polymorphism among lines and are useful tools for fingerprinting and categorizing of maize genotypes into different groups. This feature can be used in determining heterotic groups and prediction of heterosis in maize hybrid production.

Maize (Zea mays L.) is one of the most cultivated crops worldwide, owing to its versatility and wide adaptability, and serves as food, animal feed, and raw material for various industrial products. The purpose of the current research was the classification of maize inbred lines in order to produce hybrid seeds based on agro-morphological traits. Each of 100 maize inbred lines was planted in 6 pots as 6 replications and arranged in completely randomized design in an open area near to greenhouse in 2015. The result of the analysis of variance revealed significant differences among lines for all studied traits. The highest correlation was seen between cob’s length and cob’s weight. Stepwise regression analysis revealed that 66.4% of seed yield per plant variation was determined by cob’s length and cob’s weight. Cluster analysis divided inbred lines into 4 groups. The highest Mahalanobis distance (28.07) was observed between cluster 2 and 4. The result of principal component analysis confirmed the calcification by cluster analysis. The genotypes from groups 2 and 4 can be potentially used as parental lines in hybrid varieties production and development of segregating populations.

Maize (Zea mays L.) as a model plant is important from agricultural, feed and industrial point view. Most of economically important traits and morphological traits are controlled by several genes and also influenced by environment effects and hence possessed complicated genetic control. This research was aimed to study the genetic control and identification of genomic regions controlling agro-morphological traits in maize germplasm using association analysis approach. Maize inbred lines were evaluated based on morphological and 16 ISSR primers. Results of morphological and genetically evaluations trials revealed existence of genetic variability in the studied germplasm which is mandatory item for successful association analysis study. Analysis of population structure using 81 ISSR loci divided the population into 2 sub-populations. Among studied lines, lines 1387/193/chase (Mashhad population) and 66*1388 (Mashhad population) showed maximum genetic admixture. Association analysis using MLM model represented 25 ISSR loci which possessed significant relation with studied traits. Positive markers identified in this research, could effectively applied in marker assisted selection programs to achieve suitable parental lines and also improvement of trait of interest. Also, this is resulted that inter simple sequence regions have acceptable ability and performance in association mapping of maize.