Kishu Mandarin

UCR identifies its Kinokuni/Kishu accession as CRC 0696 / PI 539270, received as seed from P. J. Wester in 1915; parents are unknown. A 1967 account reproduced there calls Kishu an old mandarin of Chinese origin and one of the earliest introduced into Japan, but the exact origin and introduction date are unknown. Shimizu (2022) reports historical and genetic literature placing Kishu in Japan by at least 740 CE and in pedigrees of other Japanese citrus; these accounts do not establish every plant labeled Kishu.^{⁠[22]⁠[19]}

The 1967 description calls fruit small, somewhat oblate and flattened at both ends, orange and glossy, with a thin, tight aromatic peel, firm meaty flesh, few polyembryonic seeds and early-midseason maturity. Individual contemporary tastings vary: some generic Kishu fruits are described as very sweet or minimally sour, and several are reported seedless; these are sample-specific reports, not a cultivar-wide sensory score or seedlessness guarantee.^{⁠[22]⁠[13]⁠[14]⁠[15]⁠[16]⁠[17]}

Nursery and grower sources describe dwarfing or productive Kishu trees, including a 22-year-old C-35 tree that is regularly pruned. Separate forum accounts report heavy fruit loads, fruit drop and defoliation after a heavy set; these are reports from different trees, and no causal explanation or general yield estimate is established.^{⁠[3]⁠[9]⁠[13]⁠[18]}

McClendon gives different accounts for his in-ground Kishu across years: after a protected 2022 cold spell at “11°” the tree died back but recovered; before a 2024 tasting, he says it had no damage after a brief “16 or 17°” exposure without protection. Neither video states units; these are different cold events, not a minimum-temperature test.^⁠[6]⁠[7]

UCR distinguishes Kishu/Kinokuni from seedless Mukakukishu: its CRC 0696 page notes a seedless form imported in 1979 as CRC 3887, while a separate CRC 3906 accession is listed as Seedless Kishu and received as budwood from Japan via Glenn Dale in 1983. Seedless fruit in generic Kishu reports does not identify the distinct seedless selection.^{⁠[22]⁠[1]}