In Korea, consumer demand for seedless grapes with high quality and large berries is increasing. Although a lot of effort into introducing European stenospermocarpic grape cultivars in Korea has been made, it did not work because they were not adaptable to growth conditions in Korea. In Korea, most seedless grapes are currently produced by applying plant growth regulators twice, using seeded grape cultivars such as Kyoho and Shine Muscat. Because this method is time-consuming and labor intensive, it is becoming more important to breed and introduce seedless grape cultivars that can reduce labor and time. The characteristics of parthenocarpy, stenospermocarpy, and triploidy, which are found in grapes, have been applied to breeding seedless grapes (Heo et al., 2007; Pratt, 1971; Stout, 1936). Recently, hypo- and hypertetraploids have also been suggested as a good way to breed seedless grapes with large berries. Hypo- and hypetetraploidy are a sort of aneuploidy, and refer to the loss or the gain of individual chromosomes from the tetraploid chromosome set. They show similar growth characteristics with tetraploid grapes, but they do not have the fertility of pollen. Hence, they provide the chance to produce seedless fruit with large berries via a one-time application of a growth regulator during the full blooming period (Park et al., 2015). Despite such an advantage, no hypo- or hypertetraploid grape cultivar—with the exception of ‘Takao’, which is a chance seedling from the open-pollinated tetraploid Kyoho—has been released worldwide because the occurrence rate and identification of hypo- and hypertetraploid seedlings is extremely low and difficult, respectively (Park et al., 2016). To improve breeding efficiency for the development of hypo- or hypertetraploid grape cultivars, we tried to establish a system for identifying and producing hypo- and hypertetraploids more easily. During this process, we also investigated their growth and fruit characteristics for the past 15 years. As a result, we have released the hypotetraploid grape cultivar Hanareum, with its excellent horticultural characteristics.
Heo, J.Y., Park, K.S., Yun, H.K. & Park, S.M. 2007 Degree of abortion and germination percentage in seeds derived from interploid crosses between diploid and tetraploid grape cultivars Hort. Environ. Biotechnol. 48 2 275 276
Park, Y.S., Heo, J.Y. & Park, S.M. 2016 Production of hypo- and hypertetraploid seedlings from open-, self-, and cross-pollinated hypo- and hypertetraploid grape Korean J. Hort. Sci. Technol. 34 5 275 276
Park, Y.S., Heo, J.Y., Um, N.Y., Bang, S.B. & Park, S.M. 2015 Growth and fruit characteristics of hypo-, hyper-tetraploid grapes Korean J. Breed. Sci. 47 3 275 276
Park, Y.S., Kim, I.J. & Park, S.M. 2010 Selection of hypo- and hyper-tetraploid seedlings from abnormal cotyledons seedlings obtained during crossing of tetraploid grapes (Vitis complexes) Korean J. Hort. Sci. Technol. 34 5 275 276
Stout, A.B. 1936 Seedlessness in grapes. New York State Agr. Expt. Sta., Tech. Bull. no. 238