Effects of seasonal variation in temperature and cultivar on yield and yield determination of irrigated groundnut (Arachis hypogaea) during the dry season in the Sahel of West Africa
Br. Ntare et al., Effects of seasonal variation in temperature and cultivar on yield and yield determination of irrigated groundnut (Arachis hypogaea) during the dry season in the Sahel of West Africa, J AGR SCI, 131, 1998, pp. 439-448
In the Sudano-Sahelian zone of West Africa there is potential for groundnut
(Arachis hypogaea L.) to be grown as a dry-season crop where irrigation is
available. However, there are substantial variations in the temperatures d
uring the post-rainy season that can be expected to influence growth and yi
eld. An experiment at the ICRISAT Sahelian Centre was done in order to stud
y the effect of sowing date on phenology, yield and the processes of yield
determination for four groundnut cultivars under irrigation in the dry seas
ons of 1990/91 and 1991/92. Starting on 15 November, eight sowing dates at
2-weekly intervals were tested. Sowing date significantly affected phenolog
y (time to emergence, flowering and maturity) with groundnut sown in Novemb
er/December taking the longest time to reach these phenological stages. Nov
ember and December sowings gave the highest pod yield within each year, des
pite the lowest crop growth rates (B), and yield declined progressively as
sowing occurred later (50 % decrease by March) despite increasing B. The ob
served responses appear to have been due to the effect of temperature diffe
rences during the pod-filling phase on partitioning. Partitioning (p) to po
ds was optimized at c. 30 C, with some indication of cultivar differences i
n partitioning response to temperature. Across all the environments, cultiv
ars displayed substantial differences in yield stability. When sown late, y
ields were low and lines with high partitioning were the best. When sown ea
rly in the post-rainy season, cultivars with a high B value were the better
choices. Plant habit differences and B suggest that radiation interception
was a limitation to yield, particularly when the crops were sown in the co
ol months of the year. However, haulm yield and crop growth rates were not
consistently affected by sowing date across the years, and cultivars demons
trated different degrees of stability for B. It is concluded that where pod
has a price advantage over fodder, irrigated groundnut for the dry season
should be sown in November to allow the crop to develop under the relativel
y cool temperatures that maximize pod yield. Further agronomic research is
suggested to maximize B for individual cultivars for given sowing dates.