Abstract:
The phenological development, growth, yield and yield stability performance of eight
cowpea varieties released in Ghana between 1990 and 2015 were evaluated in field
experiments carried out at Mampong-Ashanti (forest-savannah transition zone) and
Fumesua (forest zone) over two cropping seasons in 2015 and 2016. The experiments were
arranged in a randomized complete block design (RCBD) with three replicates. Asontem,
Nhyira, Asetenapa, Hewale and Videza flowered and podded earlier (37-44 days and 49-
51 days, respectively) than Soronko, Tona and Asomdwe (46-48 days and 52-55 days,
respectively). Hewale, Asomdwe, Asontem and Videza by virtue of their erect and semierect
architecture had the highest plant height in both seasons, while Tona recorded the
lowest. Crop growth rate among the varieties ranged from 1.1-1.7 g/m2/day for Asetenapa,
Tona and Videzea to 2.3-3.3 g/m2/day for Asontem, Nhyira, Soronko, Hewale and
Asondwe. Pod yield ranged from 980-2540 kg/ha, with Videza and Soronko producing the
lowest pod yields, while Asontem had the highest pod yield across both locations and
cropping seasons. Seed yield ranged from 603-2241 kg/ha, with Asetenapa yielding the
lowest (603-1407 kg/ha). Asontem produced the highest number of pods per plant and
number of seeds per pod and thus the highest seed yields (1240-2241 kg/ha) over the
locations and seasons. Pod harvest index ranged from 0.58-0.90. The four yield stability
analysis methods used showed that Asontem and Tona were the most stable varieties and
were adapted to all the environments, while Soronko and Asetenapa were the least stable
and were adapted to more favourable environments.
Description:
A thesis in the Department of Crops and Soil Sciences Education,
Faculty of Agricultural Education, submitted to the School of
Graduate Studies in partial fulfillment
of the requirements for the award of the degree of
Doctor of Philosophy
(Agronomy)
in theUniversity of Education, Winneba
FEBRUARY, 2020
