Introduction: Phalaris aquatica L. (Poaceae), is perennial grass. It passes summer drought as buds at the base of reproductive tillers attached to the deep root system. Genotypes of Ph. aquatica show a range of incomplete endogenous dormancy. P. aquatica, 2n=4x=28, is an allopolyploid or segmental allotetraploid. Many forage grass species have estimated the heritability of different agronomic traits. The selection could be operated on a highly heritable trait related to a more complex trait such as forage yield.
Evaluation of genetic diversity and study of relationships between traits based on morphological and agronomic traits can be helpful for organizing germplasm, selecting parents for hybridization, and producing segregating populations. Despite the importance of forage plants in country's animal husbandry, not much attention has been paid to the category of breeding and introduction of suitable forage plants in comparison with other crops. The main purpose of this study was to investigate Phalaris aquatica as a forage species in order to identify the desired genotypes for use in breeding projects.
Materials and Methods:The twenty-six Phalaris aquatica genotypes were selected from a large replicated nursery established, mainly consisting of natural ecotypes of Phalaris aquatica from broad geographical areas of Iran. A study was implemented using 26 selected Ph. aquatica genotypes in a randomized complete block design (RCBD) with three replications in the Research Field of the Agricultural Biotechnology Research Institute (ABRI) of northwest and west region of the country in Tabriz. The Ph. aquatica genotypes were examined in terms of morphological and agronomical traits, seed and forage yield. Evaluated traits were number of days to flowering, number of days to pollination, plant height, spike length, number of stems, dry matter yield, crown diameter, flag leaf length and flag leaf width. Before performing a data analysis, the assumptions of analysis of variance was tested.
Results and Discussion: The results of analysis of variance (ANoVA) showed the existence of genetic diversity among selected Phalaris aquatica genotypes. Mean comparisons also showed that genotype Ph.aq-3 had the highest number of stems and genotypes Ph.aq-6 and Ph.aq-26 had the lowest number of stems per plant, respectively. The largest diameter of the canopy with 48.89 cm was related to genotype Ph.aq-12. Results of correlation analysis showed that dry forage yield has a positive and significant correlation with traits such as spike length, seed yield, number of stems, crown diameter and canopy diameter. In principal components analysis, four components were identified, which in total explained 84.3% of the total variance of the variables. In the first principal component, traits such as dry forage yield, crown diameter and canopy diameter, in the second component, only the leaf length and in the third component, traits such as number of days to flowering and number of days to pollination had the highest coefficients. Cluster analysis also classified the studied genotypes into six sub-clusters. Considering traits such as yield and yield components, genotypes in the third sub-cluster can be a good choice for cultivation. Also, the maximum genetic distance was obtained between the third sub-cluster and the fifth sub-cluster, which according to the goals of the breeder, the genotypes of these two sub-clusters can be used in breeding programs for exploiting their desirable genes.
Conclusion: In conclusion, results of present research indicated low genetic variability in the studied Ph. aquatica genotypes and some genotypes with high production capacity or other desirable traits can be used in Phalaris aquatica breeding projects. Genetic diversity can be used at breeding genotypes to biotic and abiotic stresses. However, the studied Phalaris aquatica genotypes will deliver valuable germplasm to employ in Phalaris aquatica breeding programs for forage cultivar production.