Although all reported attempts to date to hybridize maize with sorghum have failed, the results do offer a certain element of encouragement. Any attempt to produce a fertile hybrid that can serve as a bridge to the exchange of germplasm between these two important crop species is worth trying.
Maize and sorghum materials used in the hybridization program are listed in the Table. Maize stocks used as females were planted in isolation from their male counterparts and were detasseled as a measure of reducing contamination from stray pollen. Also, male sterile sorghums were isolated from male fertile sorghums. A total of 923 reciprocal controlled pollinations (480 maize x male fertile sorghum and 443 male sterile sorghum x maize) were made by conventional methods. In general, silks were shortened. Salicylic acid (10-2 M) solution was sprayed on male sterile sorghum heads and maize silks.
A total of 67 'potential' hybrid seeds (46 from maize female and 21 from sorghum female) were recovered. Approximately 60% of these seeds have been transplanted into clay pots. With the exception of two, all of those showing near normal growth turned out to be parthenogens or contaminants. The two 'potential' plants (SC 440 female x CSH-5 male) have reached maturity with slow growth and were morphologically more similar to maize than to sorghum. None of them gave viable pollen. Further work on the production of maize x sorghum hybrids with suitable genetic markers is in progress.
B. Ramesh and G. M. Reddy
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