Genetic selection of fig tree (Ficus carica L.) varieties using phenotypic characteristics of rooting and development of softwood cutting

Abstract

Although fig tree cultivation has been expanding in Brazil, there is paucity in literature on improvements necessary to propagate it at different environmental conditions. Therefore, this study aimed at assessing quality and genetic potential of thirty fig tree varieties from the germplasm bank for phenotypic analysis of root and softwood cuttings development. The softwood fig cuttings collected from pruning branches of selected varieties. We standardized cuttings of 20 cm in length having straight cut at the basal part and a bevel at the apex. They were placed into the polyethylene box (50 x 17 cm) filled with medium textured expanded vermiculite in a vegetable stove. We used intermittent nebulization irrigation with a flow rate of 0.012 m3s-1 of water in 20 seconds each 3 minutes. After 60 days, cuttings were transplanted into plastic bags (30 x 20 cm) with capacity of 1.2 L filled with 1/3 soil and 2/3 organic compounds, where placed in a greenhouse, protected with 50 % shade black polypropylene mesh, with intermittent irrigation for 15 minutes with a flow rate of 0.243m3s-1 every 4 times a day. After 105 days, evaluations consisted of cuttings survival number, length of the largest root, root fresh and dry matter, shoot number, length of the largest shoot, shoot fresh and dry matter. The results of analyses showed Roxo de Valhinhos, Ilha Solteira, Brunswick, IAC, Genoveso, IAC, varieties 39, 41 and 42 as high performance varieties. In addition, results indicated low genotypic coefficient of variation in relation to environmental coefficient of variation in most characters. Besides, only two characters showed superior heritability; thus, we concluded that there is no genetic variability between varieties for most measured characters. Since the studied population presented low genetic variability using morphological descriptors of roots we recommend unsuccessful selection for tested characters through breeding programs. However, cuttings survival number is of great importance to select fig genotypes.