2022 Volume 67 Pages 7-15
To explore alleles for the higher number of spikelets per panicle of a super-extra-heavy panicle cultivar of rice, Tsubumasari, the present study examined the nucleotide sequences of a locus for spikelet number, GN1A, in this cultivar and its parents, Milyang 23 and Nanjing 11, and also Habataki. Results of the sequencing of GN1A showed a total of 50 nucleotide polymorphisms, including substitutions, insertions, and deletions, in the coding sequence and untranslated regions in the group of Milyang 23, Tsubumasari and Habataki, compared with Nipponbare. Nanjing 11, another parent of Tsubumasari, demonstrated all polymorphisms, except for only one substitution of G to A in the second intron found in Milyang 23 and others. Therefore, at GN1A Nanjing 11 had a novel allele differing from Milyang 23. On the other hand, Milyang 23 had the same allele as already reported for Habataki. Moreover, Tsubumasari inherited the allele from Milyang 23 at GN1A. From the results of the recombinant inbred lines derived from Milyang 23/Nanjing 11, the novel allele of Nanjing 11, which can be identified using a CAPS marker, tended to decrease the spikelet number per panicle through a decrease in the number of spikelets on the secondary branches per secondary branch, compared with the allele of Milyang 23.
