RA 00183.pdf - OAR@ICRISAT

Progress towards Better Adaptation of Groundnuts
for West African Conditions
J.H. Williams, D.C. Greenberg, B.J. Ndunguru, and U. Hartmond 1
Introduction
In West Africa, groundnut is exposed to a wide range of environments, and it is clear that
different genotypes are needed to maximize production in these different agroecological
regions. Inevitably, the limiting factors to groundnut production in western Africa differ with
agroecological zone. To improve yield by developing varieties better adapted to these environments,
it is first necessary to determine the limitations to productivity, and establish the
existence of useable genetic variation in response to this environmental factor. Next one
needs to develop methods to easily identify genotype attributes.
Drought Responses and Adaptation to Sahelian
Conditions
In the Sahelian region, drought is perceived as a major limiting factor. At ISC, scientists
examined the yield determination of some 36 genotypes in 5 water-supply environments. The
varieties examined included the major varieties of the region and a range of lines from the
international germplasm collection and from ICRISAT breeders in India and southern Africa.
These genotypes were grown in three treatments in the prerainy season with irrigation
providing 100%, 5 0 % , and 3 3 % of the evaporative requirements. In the rainy season, two
sowing dates were used to expose the plants to differing water deficits during the pod-filling
phase.
Averaged across these genotypes, these treatments resulted in different levels of productivity
in both total and pod yields. The greatest biomass yields were obtained in the fully
watered dry-season control treatment; but pod yields were the highest in the early-sown rainy
season control treatment. The effects of the limited water supply on growth are obvious.
The analysis of these yields in terms of the crop growth rate (C) and partitioning (p) of this
C to reproductive growth clearly showed that the superior pod yields of the rainy season
treatment are due to high partitioning. Partitioning was considerably reduced in the drycontrol
treatment, even when the crop was fully irrigated.
The regression of these yield-determining parameters for individual varieties against the
environmental mean in these treatments was particularly revealing. As the environments
were known in terms of their physical characteristics and were very similar in terms of their
1. Principal Physiologist; Former Principal Groundnut Breeder; Principal Agronomist; and Graduate Student,
ICRISAT Sahelian Center, B.P. 12404, Niamey, Niger (via Paris).
Citation: ICRISAT (International Crops Research Institute for the Semi-Arid Tropics). 1991. Summary Proceedings of
the Second ICRISAT Regional Groundnut Meeting for West Africa, 11-14 Sep 1990, ICRISAT Sahelian Center,
Niamey, Niger. Patancheru, A.P. 502 324, India: ICRISAT.
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