The goji berry (Lycium chinense Mill.) line CBP17749-20 was selected from F1 hybrids of ‘CBP02261-1’ and ‘CBP11542-206’ in 2017 to establish a cultivar suitable for shoot and leaf production. Preliminary and advanced yield trials were conducted in 2019 and 2020 to investigate yield characteristics, and the selected line was named ‘Gugisoon 2.’ After regional adaptability tests from 2021 to 2022, it was officially registered as the cultivar ‘Cheongsoon.’ The cultivar Unk ‘Cheongsoon’ is characterized by vigorous growth, strong sprouting ability, and an upright growth habit. Its leaves are broadly oval with a higher chlorophyll content than those of the control cultivar ‘Gugisoon 1’ and both leaves and stems are thicker and heavier. It also exhibits excellent resistance to gall mites (Eriophyes spp.), which cause purplish galls on leaf surfaces. Compared to ‘Gugisoon 1,’ ‘Cheongsoon’ has a higher rutin content and a lower quercetin content, and its shoot production index is 224% greater. This cultivar is highly suitable for shoot and leaf production and can be grown in open fields; however, greenhouse cultivation produces tender shoots (Registration No. 10170).

Seedlessness is the most important characteristic of citrus and one of its breeding purposes. Triploids are the most reliable way to secure seedlessness and can be developed through crosses between tetraploids and diploids or between diploids and diploids. We evaluated the characteristics of seed formation and recovery frequency of triploids in interploid crosses in this study. Normal seed formation was the highest (85.0%) in crosses of 2x×2x, followed by crosses 4x×2x and 2x×4x. Partially developed seeds were obtained at the highest rate (35.3%) from crosses of 4x×2x with 0.7 seeds per fruit, followed by 2x×2x and 2x×4x with 0.2 and 0.1 seeds per fruit, respectively. The number of undeveloped seeds per fruit was 1.1, 1.0, and 0.3 from the 4x×2x, 2x×4x, and 2x×2x crosses, respectively, and the lowest frequency was recorded in the 2x×2x cross. Diploid plants were mostly obtained in the 2x×2x cross (98.8%), while 73.0% triploids and 27.0% tetraploids were obtained with 4x×2x, and 14.3% diploids, 57.1% triploids, and 28.6% tetraploids were achieved with the 2x×4x cross. Diploid plants were mostly obtained from normal seeds, while ad triploid and tetraploid plants were mostly obtained from partially developed and undeveloped seeds. The results indicated that crosses of 4x×2x were the most efficient and that in vitro culture should be applied to rescue plants from partially developed and undeveloped seeds in triploid breeding programs.

The Goji berry line CBP06419-243 was selected from the hybrids (F₁) between CBP03310-250 (IT232705) and CBP05399-1. The line used for crossing was tetraploid induced by the colchicine treatment on bud. Preliminary yield tests using this line were performed from 2009 to 2011, and the final selected line was named ‘Cheongyang 18’, which was subsequently registered under the name ‘Whasu’ in 2015. The specific characteristics of this cultivar are summarized as follows: The flowers are distinctly larger, fruit is medium in size, long oblong, and red, and flowering commenced on June 21. Branching by pruning generated less than the reference variety Cheongmyeong. The leaf infection rates by Eriophyes macrodonis Keifer were as high as 7.7%. Anthracnose on fruits in open field was slightly more severe compared with the reference cultivar, but the infection rates in rain shelter greenhouses was similar. The content of betaine and free sugar in dry fruit was higher than that of the reference cultivar. The dry-fruit yield decreased about 13% in open field, but increased 18% in rain shelter greenhouses. The cultivar ‘Whasu’ is suitable for cultivation in rain shelter greenhouses because of self-compatibility and high yield. It is not necessary the companion cultivar (Registration No. 6345).

In this study, we investigated the fruit and vine characteristics of hypo- and hyper-tetraploid grapes from which a chromosome was added or deleted. The aim of this study was to evaluate the possibility of developing seedless grapes by utilizing the characteristics of hypo- and hyper-tetraploid grapes. Both the hypo- and hyper-tetraploid grapes showed stable vine growth characteristics unlike other aneuploid plants, which displayed abnormal leaf morphology and unstable vine growth patterns, indicating that hypo- and hyper-tetraploid grapes can be used for commercial purpose. The hypo-tetraploid grapes produced 100% seedless fruits, with large berries ranging from 8.5 to 10.5 g, when the grapes were applied with 100 ppm gibberillic acid during their full bloom period. Although the fruits of the hyper-tetraploid grape were larger than those of the hypo-tetraploid grapes, it produced a lower percentage of seedless fruits. We conclude that the characteristics of hypo-tetraploid grapes may be exploited to develop seedless grapes with large berries.