The Hebrew University of Jerusalem
The genetic basis for the first barren stalk genes was reported in 1935 (Emerson et al.). Two independent genes were found, known as ba1 and ba2. ba1 is a barren stalk gene located on chromosome 3 (Emerson, 1935). It is monogenic and recessive. All barren plants are both earless and tasselless. A normal heterozygote when self-pollinated segregates 3 normals:1 barren stalk. ba2 is a barren gene located on chromosome 2 (Emerson, 1935). It also is monogenic and recessive. All earless plants, however, produce normal tassels with viable pollen. A normal heterozygote crossed by an earless recessive homozygote produces a 1:1 ratio of normals to barren stalk (earless). The new earless trait produces an earless plant similar to ba2 in appearance, with normal tassels and viable pollen. To verify the uniqueness of the new 100% earless trait, a genetic analysis was conducted comparing it with ba1 and ba2. The results are shown here.
The uniqueness of the new earless trait is clearly demonstrated by the fact that the F1s of all the crosses were normal. If the new earless trait was allelic to either ba1 or ba2, when two heterozygotes were crossed some of the progeny would have to be homozygous recessive and therefore earless. However, all F1 progeny were normal, showing that all 3 earless traits are different from each other and give rise only to heterozygotes expressing the normal phenotype. The other unique feature of the new earless trait lies in its ability to produce 100% earless progeny.
The stalks of the new 100% earless lines were analyzed and were found to be high in sucrose, ranging from 18-21 Brix. This new 100% earless trait makes possible for the first time the economic utilization of maize for sucrose production and all of its derivatives (ethanol, sugar syrups, etc.) and for sweet earless corn forage.
The genetic basis of this trait is presently
being worked out and will be reported in the near future.
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