RA 00110.pdf - OAR@ICRISAT

Guerguera, P 3 Kolo, and Tamangagi. In 1974, the
S,s from these cultivars were recombined to produce
the composite CIVT.
In Mali, the same selection method was applied to
two late cultivars, M 5 and M 9 , and two early cultivars,
M 2 D 2 and N K K . Poor results led to this breeding
program being discontinued. In Burkina Faso,
the populations used were M 9 , M 1 2 D 9 , and Dori
millet. M I 2 D 9 showed a definite yield advantage
compared to the original population.
Conclusion: Improving Local Varieties
The programs to improve local varieties have been
successful in most countries. However, the new varieties
have not reached their full potential in farmers'
fields (Matlon 1985), and their acceptance has been
limited in most countries. Those that have been
more successful have been or are being released
(HKP and CIVT in Niger, M 2 D 2 and M 9 D 3 in Mali,
and Souna 3 in Senegal).
This slow spread can be attributed to several factors.
The improved varieties showed marginal superiority
when compared to the local controls in
farmers' fields. Monitoring by extension services
was inadequate; their potential was not fully exploited.
Improvement of local cultivars is extremely
complicated, especially in a center of diversity where
each ecotype remains location specific. The broad
range of environmental variation almost requires
breeding material for each location. Moreover, the
pearl millet breeding program, unlike those for rice,
cotton, and groundnut, had severely limited material
and human resources to carry out its work (Bono
1962).
Improvement of Grain/Straw Ratio
By the late 1960s, breeding programs were working
to reduce the grain/straw ratio by shortening the
stem, which is particularly long in most African
cultivars.
Landraces are characterized by abundant vegetative
development (Jacquinot 1972). While this is an
advantage (hardiness, adaptation to rudimentary
techniques) in traditional farming, it becomes a limiting
factor when cropping is intensified because it
affects plant response to inputs (Etasse 1972). In tall
varieties, the number of heads m -2 rarely exceeds
8-10 (Chantereau and Etasse 1976), but when it does,
there is risk of lodging. In wet areas, under adequate
cropping conditions (cultural techniques), straw
production can rise to 15-20 t for 1.8-2.5 t of grain
(Jacquinot 1972). This implies a high rate of mineral
mobilization that is disproportionate to the grain
yield. In a study comparing the nitrogen requirements
of different species, the species producing less
straw used the absorbed nitrogen most effectively
(Blondel 1971). It was evident from this study and
others conducted with other cereals, that the limiting
factors to increased production were related to the
plant structure of the landraces. Therefore, selection
of varieties with low straw production is essential to
intensify pearl millet cultivation.
I R A T attempted to reduce straw production by
transferring the dwarfness gene d 2 from the line 125
to local cultivars. 125 is an introduction from India,
with less foliage, good tillering habit, and vigorous
heading. The gene was transferred to cultivars
Souna (Senegal), Haini Kirei Normal (Niger), Ex
Bornu (Nigeria), and N K K from Seno (Mali).
The program to breed dwarf populations by backcrossing
was started in 1968 in Senegal and continued
in Niger, Burkina Faso, and Mali. Apart
from reduced height, the new pearl millet varieties
were expected to have a medium tillering potential,
upright structure suited to denser plant stands, and
tolerance to local pests and diseases.
Stages in the Improvement of the
Grain/Straw Ratio
In Senegal, the dwarf line I 25 was crossed with the
improved local cultivar Souna 2. The resulting 1/2
Souna was selected for mildew resistance until 1973.
Certain lines were taken from this program to serve
as parents in the Niger and Mali programs.
Because of mildew and smut susceptibility and
poor heading in 1/2 Souna, it was decided to
develop another population, without these defects.
This was 3/4 Souna. After 1973, the entire breeding
program was moved to the Tarna Station in Niger,
where dwarf populations 3/4 Haini Kirei and 3/4 Ex
Bornu were developed. A trial comparing the local
1/2 and 3/4 populations confirmed a 50% increase
in individual grain mass in 3/4 Souna compared to
1/2 Souna. After 1974, the three dwarf populations
were further selected for uniform agronomic characters.
In Mali, dwarf population 3/4 seno was obtained
from variety N K K in 1976. Cumulative recurrent
selection was aimed at eliminating the major defects
(unsuitable crop duration, staggered flowering, and
smut and mildew susceptibility).
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