RA 00048.pdf - OAR@ICRISAT

uncertain moisture are the rule in the West
African SAT except for minor areas with irrigation
or along river fioodplains.
Sorghum Varietal Improvement
A great majority of farmers in the West African
SAT follow traditional farming practices that have
evolved through generations (Swift 1978) and
reflect adaptation to the variable environment.
Improved varieties and hybrids should be developed
to fit these systems if production by
farmers, most of whom are near the subsistence
level, is to be increased. The failure to have done
this may explain the general lack of success of
sorghum improvement programs in the region.
Results of Sorghum Varietal
Improvement in West Africa
During the early 1960s the Institut de Recherche
Agronomique Tropical (IRAT) started work on
sorghum varietal improvement in West Africa
south of the Sahel. Several promising varieties
have been developed in Senegal (Mauboussin et
at. 1977). However, in spite of a well-established
agricultural research infrastructure as well as a
regional experimental unit, Sene (1980) believes
that these varieties and research findings have
had little impact at the farm level. In Mali and
Niger, Sapin (1977) and Chanterreau and Mousa
(1977) report that several HYVs have been identified
for use by farmers, but Johnson (1979)
concludes that in Mali local varieties outyielded
the improved ones under moderately superior
management conditions.
In Upper Volta, Labeyrie (1977) listed a number
of promising varieties. For the northern zone, with
400-500 mm/year rainfall. IRAT S-10 and S-13
were recommended. However, S-10 has proved
too late and S-13 required precise soil management
for seedling establishment, with the result
that neither variety has been generally adopted by
farmers. For the 650-750 mm/year rainfall zone
(central Upper Volta) several selected local
varieties, such as IRAT S-29. Nongomsoba, Belco,
Zalla. and Tioadi, were recommended. But again,
none is grown on a large scale probably because
they are not different from or superior to local
varieties already in use. Other dwarf, partially
photoperiod-sensitive, improved varieties recommended
for the same rainfall zone, such as IRAT
S-6, S-7, S-8, and S-10, also have not been
adopted because of poor seedling establishment
or poor grain quality. In the higher rainfall zones in
the south of Upper Volta tall, late-duration,
selected local varieties such as Ouedezoure and
Gnofing have been relatively more successful, but
other improved varieties, such as IRAT 271 and
294, have not been adopted because of poor grain
quality.
ICRISAT Sorghum Improvement
Program in Upper Volta
ICRISAT sorghum improvement work in West
Africa started in 1975. During the following years
a range of elite introductions and local varieties
have been identified and concepts on varietal
requirements have been defined (ICRISAT 1980).
Varietal requirements were considered against
variations in rainfall (amount, duration, and distribution),
soils (their water-holding capacities), and
local farming practices (type of soil preparation,
planting dates, and fertilization practices) for the
major zones in Upper Volta. As a result sorghum
improvement and selection of cultivars of three
broad maturity durations were initiated.
a. Long-duration (130-140 days), photoperiodsensitive
sorghum to be planted at the onset
of the rains in late May or early June on good
deep soils or in low-lying areas where
residual moisture is assured at the end of the
rainy season. Presently, only local varieties
or "improved" locals, outstanding in germination
ability, seedling vigor, and drought
tolerance, are available. With judicious selection
of progenies from crosses of selected
locals x elite exotics it may be possible to
isolate lines with the hardiness of the locals
and the higher yield potential of the exotics.
Such work is in progress.
b. Medium-duration (120 days), partially photoperiod-sensitive
sorghums for planting in the
600-800 mm/year rainfall zone by the
second half of June, or in higher rainfall
zones in case of an early drought, providing
an additional option as well as a means to
spread the early-season workload over a
longer period of time.
c. Short duration (less than 105 days), photoperiod-insensitive
sorghum that can be
planted in July in the northern zone, in the
central zone on shalow soils, and as a "last
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