OCCURANCE OF INTERMEDIATE FORMS (SHIBRAS) IN CULTIVATED FIELDS OF PEARL MILLET

Abstract

Pearl millet (Pennisetum glaucum (L.) R. Br.) cultivated over more than
2 m ha annually ranks 1st in the area and production in the Republic of
Niger, West Africa (Singh and Ouendeba, 1977). Niger falls within the
region of pearl millet domestication (Brunken et al. 1977), where wild,
weedy and cultivated forms occur in aboundance. Cultivated pearl millet
crosses with its wild relatives such as subspecies monodi (formarly known
as violaceum) and fallax which result into creation of intermediate weedy
forms which occur abundatly in many cultivated fields (Brunken et al.
1977). These intermediate forms continue to cross and back cross with
cultivated types and inter cross among themselves appear to be the major
factor land varieties inWest Africa (Scholz, 1979).Thoughvariousfarmers
try to eliminate the weedy forms at various stages, the intermediate forms
called shibras perpetuate in the farmers fields with varied morphologies,
ranging from the forms close to cultivated pearl millet to their wild
proginators. Since the crop is cross fertilizing, the genes for shattering
persist in the non shattering forms.