Bisexual flower ontogeny after chemical induction and berry characteristics evaluation in male Vitis amurensis Rupr

The sex of the male Vitis amurensis Rupr (Amur grape) flower can be converted to a hermaphrodite form after treatment with N-1-(2-chloro-4-pyridyl)-N-3-phenylurea (CPPU). This paper describes the results of flower development studies using histological approaches, and evaluates the pollen germination and berry characteristics. In wild-type male grapes, pistil development was arrested prior to the formation of the four-nucleate embryo sac, and the pistil subsequently degenerated. In contrast, CPPU accelerated pistil development, and induced octonucleate embryo sac maturation. Stamen development of CPPU-treated males was similar to control, but pollen germination was lower than control. Also, berry characteristics differed significantly in various male Amur grape lines. Results showed that sex expression of the male V. amurensis Rupr appeared to be sensitive to CPPU that stimulated pistil development to the same extent in hermaphroditic flowers. These data may provide additional germplasm information for evaluation of the male Amur grape, and our data may influence future breeding programs and drive molecular mechanism-based studies of plant sex determination. (C) 2013 Elsevier B.V. All rights reserved.