JOHNSTON, IOWA
Pioneer Hi-Bred Int., Inc.

Two new alleles to male-sterile mutants ms2 and ms8
--M. R. Trimnell and M. C. Albertsen

Two new male-sterile mutant alleles were identified in elite proprietary breeding material. MCA observed a selfed progeny row segregating for male-sterile plants at our research station at Garden City, KS, in 1987. We grew remnant seed in Johnston, IA, in 1988 and observed a segregation of 11 male fertiles to 6 male steriles. Two male-sterile plants were sibbed with two male-fertile plants in the row, resulting in the following:
    Ear #1 7 male fertiles 7 male steriles
    Ear #2 12 male fertiles 1 mostly fertile (shedder)
The 7 male-sterile plants were testcrossed with known heterozygotes of the male-sterile mutants listed in Table 1. Progenies were grown in Johnston in 1989. At least 15 plants were observed per row. As shown in the table, there was a segregation of 10 male fertiles to 10 male steriles among the ms2 testcross progeny. Our designation for this new allele is ms2-GC87A.

The other allele was observed in our Hawaii winter nursery in 1987 by Mr. George Peverly, G. He observed a selfed progeny row segregating for male sterility from our research station at York, NE. The male-sterile plants were crossed with A632, and progenies were grown in Johnston in 1988. All plants were male fertile, so self pollinations were made. The next summer, progeny from two ears were grown with the following results:
    Ear #1 13 male fertiles 2 male steriles
    Ear #2 17 male fertiles 1 male sterile
We decided to conduct the allelism tests even though the p2 value was marginal (4.45; .05> P >.025). Only three male-sterile plants could be used in testcrosses, so fertile plants were selfed to determine heterozygosity and testcrossed with male steriles from known male-sterile plants. These progenies were grown in Johnston in 1989, and results are given in Table 1. At least 15 plants were observed per row. Allelism was observed when ms8 was used as a heterozygous male. Segregation was 9 male fertiles to 8 male steriles. Our designation for this new allele is ms8-YK87A.

Table 1. Testcrosses made to two spontaneous male-sterile mutations occurring in elite proprietary breeding material.
 
Known male sterile
ms2-GC87A ms8-YK87A
ms1 All Fertile All Fertile
ms2 10 fert : 10 ster All Fertile
ms5 All Fertile --
ms7 All Fertile --
ms8 All Fertile 9 fert : 8 ster
ms9 -- All Fertile
ms10 -- All Fertile
ms11 -- All Fertile
ms12 All Fertile --
ms13 -- All Fertile
ms14 All Fertile --
ms17 -- All Fertile


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

Return to the MNL 67 On-Line Index
Return to the Maize Newsletter Index
Return to the Maize Genome Database Page