2021 Volume 20 Issue 3 Pages 351-359
In Japanese radish, internal browning is a physiological disorder caused by exposure to high temperatures. Due to the increase in global warming, it is feared that damage caused by this disorder will severely affect the stable summer production of the Japanese radish. We evaluated the tolerance to internal browning in 294 accessions of Japanese and other radishes. A local variety from Okinawa Prefecture, ‘Shimadaikon,’ was selected as the breeding material. As a result of repeated selections of progenies derived from the cross between ‘Shimadaikon’ and fixed line 10P13 under high-temperature conditions, we developed ‘Daikon chukanbohon No 6 go’, a Japanese radish parental line with a high tolerance to internal browning. ‘Daikon chukanbohon No 6 go’ showed stable tolerance to internal browning in eight test sites including Tsu, which has a high summer temperature. Several genes were involved in the tolerance to internal browning in this variety, and the tolerance was expressed as incompletely dominant in the F1 generation. In the F2 generation, a relatively large number of individuals showed the same tolerance level as ‘Daikon chukanbohon No 6 go’.
