RA 00110.pdf - OAR@ICRISAT

the weedy form can significantly increase production
of the related cultivated variety (Tompa 1983,
Williams and Andrews 1983).
Other Parasites
Birds are a real danger in certain zones; their incidence
varies each year. The most important species
is Quelea quelea (Rachie and Majmudar 1980, Pradat
1962). Birds are responsible for low yields in
early pearl millet crops but certain bristled cultivars,
Sarakoua in Niger and Konotine in Mali, are supposed
to be relatively tolerant to bird attack; however,
they are equally susceptible in the absence of
nonbristled cultivars.
Pearl Millet Characteristics
in West Africa
General
West Africa is probably where pearl millet originated,
and also the region where the greatest morphological
diversity is found. The two other noncereal
forms of the section Penicillaria are found in
Africa. Pennisetum purpureum or elephant grass, is
a perennial tetraploid, probably an amphidiploid
derived from a cross between an unknown millet
diploid with an ancestral form of P. americanum
(Bilquez and Lecomte 1969). The second form, P.
monodii, is an annual diploid species that crosses
spontaneously with cultivated millets to produce
vigorous and fertile hybrids called n'doul in Senegal
and shibra in Niger.
Pearl Millet Variability in West Africa
Only the cultivated form shows phenotypic variation
(Bono 1973, Grouzis 1980), probably due to selection
pressure exerted by man who has unconsciously
selected a large range of cultivated types to suit
different ecological zones. Large ethnic migrations
may have contributed to increased variability, which
became less location specific (Marchais 1982). This
variability is too large and different in each country
to group the material, but common practice is to
group them according to crop duration. Since the
domestication of pearl millet, farmers everywhere,
especially in the Sahelian and Sudanian-Sahelian
zones, have established two groups, commonly
called early and late varieties. The notion of earliness
and lateness is relative and varies with each location.
The importance of each group depends on the geographical
location of the country; a north-south
gradient of decreasing earliness can be observed.
When early cultivars are grown with late cultivars,
they are considered as "hungry-season" crops.
After the recent drought, there appears to be a
general extension in the cultivated areas of early
varieties. In Niger, the variety Ankoutess can be
found further south of its original limit (ORSTOM
1976) and in Senegal, cultivation of late varieties has
almost been abandoned, and they are being replaced
by the early Sounas. Under adequate rainfall conditions,
early pearl millets yield less than late varieties.
Although the late varieties are potentially more
productive, they are not suited to low-rainfall conditions.
This unstable production pattern is related to
rainfall. Farmers therefore usually intercrop the late
varieties with a stop-gap crop (early millet, cowpea,
maize, etc.) to reduce risk.
Four years of comparative trials of Sounas and
Sanios in Senegal have shown the superiority of the
Sounas (Table l)(Etasse 1970). Consequently, breeding
programs in Senegal are focused on the improvement
of Souna varieties.
Variability of Different Characteristics
Local cultivars exhibit great morphological variability
for a large number of characters. Bono (1973) has
evaluated certain characters:
Head length. The greatest variability for this character
is found in Niger where length varied from
8-210 cm (Bono 1973). These leads are not very
compact, and conical shapes appear to be more
Table 1. Comparison of the yields of Souna and Sanio
cultivars during a trial conducted in Senegal.
Year
Planting
date
1965 9 Jul
1966 8 Aug
1967 5 Jul
1968 15 Jul
Source: Etasee 1969.
Rainfall
(mm)
603
567
843
357
Yields (kg ha -1 )
Souna
2300-2400
1700-2000
2100
1700-2000
Sanio
1700-1800
2500
1700
97