GrainGenes

II.28. Further information of the rnt locus on chromosome 3.

Shunji Nonaka, Tochigi Agricultural Experiment Station, Minarikawachi Division, Minamikawachi, Tochigi-ken, 329-04, Japan.

In a previous paper (BGN 3) it was shown that a gene rnt for reduced number of tillers in a uzu type cultivar, Mitake, was on chromosome 3. A further linkage study of rnt was performed using crosses of Mitake with two marker stocks, Absent lower laterals and Russian 82. The results are shown in Tables 1 and 2. Because both Absent lower laterals and Mitake were characterized by a reduced number of tillers, the F2 segregation of normal vs. less tillering capacity was expected to occur in a 9:7 ratio, if the character pair was independent. The data in Table 2 clearly indicate linkage between rnt and als. A map of five genes on chromosome 3, constructed from the data obtained in this experiment and those cited from Takahashi (BGN 3, p. 84), is shown in Figure 1. Thus, it was known that rnt is located between als and uz.

Table 1. F2 data for linkages of three genes, rnt, uz and al obtained in the cross of Mitake with Russian 82.

Table 2. F2 data for linkage of two genes, rnt and als obtained in the cross of Mitake with absent lower laterals.

Figure 1. The suggested arrangement of 5 genes on chromosome 3.

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