New chromosome 10 male-sterile mutant: ms49 --Trimnell, MR, Fox, TW, Albertsen, MC In the 1992 Hawaii winter nursery, Tony Stefani identified male-sterile plants segregating in the public inbred line ND203. He made sib pollinations with these male-sterile plants and gave the seed to us to grow in our 1993 Johnston, IA, nursery. These progenies did not segregate for the male-sterile phenotype, so they were self-pollinated. We did not grow these again until the 1995 Hawaii winter nursery. We planted two selfed ears in our nursery, and they segregated as follows:
 
Genotype
No. Fertile Plts.
No. Sterile Plts.
X2(3:1, P>0.050=3.84)
ND203 #)1
9
2
0.27
ND203 #)2
9
8
4.41

These male-sterile plants were then crossed with B73 and A632, and these F1 plants were self-pollinated. Their progeny were grown in our 1996 Hawaii nursery, and they segregated as follows:
 
Genotype
No. Fertile Plts.
No. Sterile Plts.
X2(3:1, P>0.050=3.84)
ND203/A632)1
11
4
0.02
ND203/B73)1
11
5
0.33

We designated this previously unknown male-sterile mutant as ms*-MB92.

In the 1998 Hawaii winter nursery, we planted the ND203/B73 F2 listed in the above data to determine the chromosome arm map location of the mutant as part of our standard procedure in working with unmapped male-sterile mutants. We first determine the chromosome arm location. Then we conduct the appropriate allele test-crosses. Leaf punches were taken from 24 male-sterile plants and from 24 male-fertile plants for DNA isolation. 96 SSR markers were used to genotype these samples. Shown below are three chromosome 10 markers that show linkage to the mutation.
 
Marker
Recomb. Alleles
Mutant Plants
% Recombination
bngl1079
1
24
(1/48) 2.1
phi062
6
24
(6/48) 12.5
phi059
5
24
(5/48) 10.4

The ms*-MB92 mutant is closely linked to bngl1079 and maps near the centromere on chromosome 10.

After receiving the mapping data, we test-crossed ms*-MB92 with the recessive male-sterile mutants found on chromosome 10 (ms10, ms11, ms24, ms29, ms47), as well as the unmapped male-sterile mutants (ms27, ms31) and those with questionable mapping data (ms35). The resultant progeny were grown in our 2001 Johnston nursery. At least 40 plants were observed for each test-cross. All test-cross progeny were found to be fertile, indicating that ms*-MB92 was not allelic. Our new designation for male-sterile mutant ms*-MB92 is ms49.
 
 


Please Note: Notes submitted to the Maize Genetics Cooperation Newsletter may be cited only with consent of the authors.

Return to the MNL 76 On-Line Index
Return to the Maize Newsletter Index
Return to the Maize Genome Database Page