For the successful implementation of breeding work aimed at obtaining various forms, new and promising starting materials are widely used in plant hybridization. To carry out the hybridization method within the process of distant hybridization, the following were used as research objects: mandarin selection forms derived from Kovano-Vase plants and the varieties Fortune Washington Navel, Early Maturing Trifoliata, and Citrus Ichangensis.
As is known, mandarins are characterized by variability of the fruit, which results in the formation of forms with features different from those of the parent plant. These acquired traits are hereditary, as they are passed down from generation to generation. Among the mandarin varieties obtained as a result of such variability, the Vase species are of interest—they differ from ordinary Unshiu by having a smaller growth habit.
As for Fortune Washington Navel, it is characterized by high-quality fruit, but its commercial spread is limited due to its low frost resistance. Therefore, one of the main problems in breeding this variety is to increase its frost resistance and develop early-maturing forms. One month after pollination, we conducted the first examination to check for fruit set and removed the isolators. Another inspection and record were made one month after the first.
Thus, the hybridization methodology in citrus breeding includes the following stages: Preparation of initial female parent components for crossing; Preparation of male pollen donors; Determination of pollen viability; Normalization and castration of flowers, isolation, pollination, and examination of fruit set.