Kimaro, Didas Rogasian
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Date
2012
Journal Title
Journal ISSN
Volume Title
Publisher
Sokoine University of Agriculture
Abstract
Development of drought tolerant cowpea varieties is an important aspect in breeding
programmes. The main objective of this study was to introgress drought tolerance into
farmer’s preferred cowpea varieties. A total of 32 cowpea lines were obtained by
crossing 1TOOK-1263 with Tumaini and ITOOK-1263 with X-Ilonga cowpea
varieties in a screen-house experiment laid out in a completely randomized design
(CRD) with a split plot arrangement in three replications. The F| lines were
advanced to Fj generation and screened for drought tolerance using box method. The
results indicate the following lines are drought tolerant ITK-TMA4. ITK-TMA10,
ITK-TMA13. 1TK-XL1 and ITK-XL9. Heritability estimates were high for all
variables in both crosses except for seed yield for plant recorded at 24.41% in a
cross between ITOOK-1263 x X-IIonga. Moisture stress during vegetative stage has
more
effect
than
moisture
stress
at
flowering
stage
for
morphological
characterization under moisture deficit. The principal components (PC) analysis
revealed that the first two PC contributed 99.65% of the total variation among the 18
cowpea genotype evaluated for cross between ITOOK-1263 and Tumaini. The PCI
and PC2 accounted for 93.85 and 5.80 of the total variation respectively. While that
of ITOOK-1263 x X-Ilonga contributed 99.78% of the total variation. The PCI and
PC2 accounted for 89.75 and 10.03 of the total variation respectively. Using the PC
analysis, this study concludes that the most effective trait responsible for variability
among the cowpea genotypes were days to 50% flowering, days to maturity and
number of seeds per plant. Further studied are recommended on drought tolerance
lines generated in this study, particularly: advancing up to F6 and evaluation for
other abiotic and biotic factors.
Description
Dissertation
Keywords
Tolerant development, Tolerant cowpe, Morphological characterization