2 research outputs found
Multilocational Evaluation of Selected Local and Improved Cowpea Lines in Uganda
Six improved cowpea ( ) genotypes intitially selected from
International Institute of Tropical Agriculture collection were
evaluated for 3 seasons at 4 locations in Uganda, with the objective of
comparing their yield performance and assessing their adaptability
under Ugandan conditions. The cowpea genotypes were MU-93, TVX
337-025(B), IT90K-109(B), KVU-12349, IT82D-516-2, and IT85F-2841.
Across locations and seasons, MU-93 produced highest grain yield (1586
kg ha -1) while KVU-12349 produced the lowest grain yield (505 kg
ha-1). At different locations the genotypes' performance varied,
whereby IT85F-2841 (1378 kg ha-1), MU-93 (1208 kg/ha), MU-93 (1235 kg
ha-1) and IT90K-190 (B) (2373 kg/ha) produced the highest grain yields
in Kabanyolo, Pallisa, Kumim and Kaberamaido, respectively. The
Additive Main effects and Multiplicative Interaction (AMMI) model was
used in the genotype by environment (GXE) analysis to determine the
yield and stability of the genotypes in the multi-environment trial.
The effect of environments, genotypes and GXE were highly significant
(P<0.001). The biplot revealed that the varieties; IT85F-2841 (G1),
IT90K-109(B) (G2), IT82D-516-2 (G3), TVX 337-025(B) (G4) and MU-93 (G6)
were generally high yielding since AMMI placed them on the right hand
side of the mid point of the axis representing the grand mean, Ebelat
(G5), Icirikukwai (G7) and KVU-12349 (G8) were generally low yielding
and were placed on the left hand side of the midpoint on biplot.
IT90K-109(B) (G2) and Icirikukwai (G7) had the highest principal
component analysis (IPCA) scores (15.4 and -22.7, respectively)
therefore were considered as unstable genotypes. Genotypes IT85F-2841,
MU-93, IT82D-516-2, KVU-12349 and Ebelat had moderate IPCA 1 scores;
hence moderately stable. TVX337-025(B) had a low IPCA 1 score and thus
was relatively a stable genotype. Within environments AMMI and
unadjusted means ranked genotypes differently. However, at one location
in 2003, 6 out of 8 genotypes were ranked similarly by both estimates.
While AMMI alone ranked MU-93 is superior in 6 out of 12 environments.
MU-93 has now been recommended for official release inn Uganda