Phenotypic variability of Fig (Ficus carica L.)

Abstract

The fig (Ficus carica L.) tree has not been subjected to intensive plant breeding programs, and thus many fig tree populations exhibit rich genetic biodiversity that could only be fully exploited once it is properly identified and classified. Traditionally, the plant germplasm characterization with the aim of its conservation has been carried out using morphological or agronomical traits. Despite the progress in elaborating descriptors, fluctuations among years, environments, or repetitions have made its application difficult until recently. These fluctuations are significant in common fig tree germplasm, and consequently, the cultivar identification is very difficult for this species. Particularly, a high vagueness and incongruence have been found in the locally cultivated accessions. Therefore, selecting highly discriminant variables is essential to optimize resources for a feasible morphological characterization. This is especially important in a crop such as a fig fruit with hundreds of genotypes described worldwide in which many synonymies and homonymies may be observed. Presumably, the most reliable method for proper investigation and optimizing resources of reliable and highly discriminant variables for a feasible morphological characterization and to detect separation of genotypes (varieties, cultivars, and accessions) is vegetative propagation and thus cloning of a homogeneous and uniform genotype and planting them in different regions with different climatic conditions and of course with a specific nutritional program. Then, under different environmental and geographical conditions, it is possible to diagnose stability and instability in the measured qualitative and quantitative morphological traits in that cultivar. In this way, the altered and environmentally affected traits can be ignored, and as a result, valid and stable morphological and distinctive traits in that cultivar could be obtained. Also, in this method, a pattern for unstable traits in different climatic conditions as additional side information for different cultivars could be defined.