Title: Research highlights
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00071929/00006
 Material Information
Title: Research highlights
Uniform Title: Research highlights (East Lansing, Mich.)
Physical Description: v. : ill. ; 28 cm.
Language: English
Creator: Bean/Cowpea Collaborative Research Support Program
Publisher: Michigan State University Bean/Cowpea CRSP
Place of Publication: East Lansing
Publication Date: 1984-
Subject: Beans -- Research -- Periodicals -- Africa   ( lcsh )
Beans -- Research -- Periodicals -- Latin America   ( lcsh )
Cowpea -- Research -- Periodicals -- Africa   ( lcsh )
Cowpea -- Research -- Periodicals -- Latin America   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
periodical   ( marcgt )
Statement of Responsibility: Michigan State University Bean/Cowpea CRSP.
Dates or Sequential Designation: Vol. 1, no. 1 (1984)-
General Note: Title from caption.
Funding: Electronic resources created as part of a prototype UF Institutional Repository and Faculty Papers project by the University of Florida.
 Record Information
Bibliographic ID: UF00071929
Volume ID: VID00006
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 13864898

Full Text

Michigan State University Bean/Cowpea CRSP

Vol. 2 No. 1


Botswana/Colorado State University/deMooy

Search for More Suitable Cowpea Varieties
for Semiarid Conditions in Botswana
C. J. deMooy
Barbara deMooy
Department of Agronomy
Colorado State University
Fort Collins, CO 80523

During the past two or three years, south-
ern Africa has been in the grips of severe
drought as have other parts of the continent.
In Botswana, rainfall has been low, 265mm at
Sebele in 1983-84, amounting to little more
than one-half the record of 450mm annual
precipitation. It has also been characterized
by an unseasonal distribution, peaking two
months earlier than normal in 1982 and two
months later than normal in 1983. Periods of
drought are an inherent part of the climate
in southern Africa. During recent growing
seasons, planting opportunities were re-
stricted to two or three periods of a few days
each year. The critical nature of these
periods was not obvious until, in many
cases, it was too late. Under such extreme
conditions, very early maturing cowpea vari-
eties have a distinct advantage because there
is a higher probability that they will mature
in sixty days rather than merely survive a
hundred days of drought. Many extra-early
cowpea lines are available for testing, mainly
originating from the International Institute
of Tropical Agriculture (IITA), Ibadan,
Nigeria, but also coming from francophone
West Africa and the indigenous germplasm
of Botswana. By itself, the early maturing
character is not sufficient qualification for
selection as valuable cowpea material. Vigor
to overcome drought and high temperature
stresses in building a vegetative frame and
producing flowers and pods, resistance to
insect pests and diseases, capacity to re-

cover from near-fatal drought effects by re-
newed vegetative and generative growth are
all required traits.
Some 200 cowpea varieties introduced
from West African countries and 337 indige-
nous cultivars have been screened for desir-
able agronomic traits in field trials under
natural conditions during the first two years
of the Botswana/Colorado State University
project's life. Limited protection from in-
sects was included where necessary. Several
introduced varieties have shown superior
yield performance over a wide range of con-
ditions. Among the highest yielding lines
from IITA were TVx 1999 01F, TVx 1948 -
01F, Vita 6, Vita 9 and IT 82E-9, a short-
season variety (60-day cowpea). Grain yields
up to 1100 kg/hectare were recorded in field
trials conducted during the 1982-83 season
when most farmers produced between 200
and 300 kg of cowpeas per hectare. The top
thirty yielding varieties were retained for
further testing the following year. In addi-
tion, other varieties were retained for special
reasons. These include VEGE 1228-15, a veg-
etable cowpea line from IITA, and those va-
rieties having extra early maturity or partial
resistance to insects.
During 1983-84, yield performance was
very low due to extreme drought. High
yielders, such as IAR 355 introduced from
SAFGRAD in Bourkina Faso, produced ap-
proximately 180 kg per hectare in four-row,
replicated test plots whereas most farmers

Funded through USAID/BIFAD Grant No. AID/DSAN-XII-G-0261

failed to produce any grain. The selection
principle remained the same. Varieties ca-
pable of maintaining a satisfactory growth
habit and capable of setting seed under the
forbidding conditions were considered for
further testing.
The first variety released was ER7. Origi-
nally derived from IITA, Nigeria, ER7 is a
vigorous producer under Botswana condi-
tions and matures extremely early. Its early
maturity, of sixty days or less from
emergence to seed, facilitates escape from
many insect attacks. Its observed partial re-
sistance to thrips is attributable to this. ER7
is not the ideal cowpea of the future, how-
ever, due to some weaknesses. For instance,
it is sensitive to aphids. In years when
aphids attack the crop at an early stage,
grain production from ER7 will be impaired.
Despite its limitations, ER7 should be a great
improvement over previously grown culti-
vars and should help farmers produce cow-
peas for home consumption during and for
some time after the current drought cycle.

Other varieties will follow after further
screening in farmers' fields over a wide
range of conditions. Not all will be early
maturing varieties for several reasons. Green
leaves from cowpea plants are harvested
during the vegetative stage and eaten fresh
as "spinach" or are stored after cooking and
drying (morogo) for consumption during the
winter when greens are scarce. These leaves
have a protein content of about six percent
and are considered an important food for
pregnant women. Early maturing varieties
have an erect growth habit and do not pro-
duce excess foliage. Any removal of leafy
material results in lower grain yield. Since
farmers need both spinach and grain, the
necessity for diversification is obvious. Fur-
thermore, there is demand for dual purpose
cowpeas producing some grain as well as
green fodder for animals near the end of the
cropping season. Such varieties generally
have a prostrate growth habit. No single var-
iety can meet all these requirements. Long-
and short-season varieties having superior

FIGURE 1: Cowpea cultivars on trial in tour-row plots at an
experimental site in Botswana.

FIGURE 2: Some introduced varieties survive and
produce seed under near-desert conditions with
265mm annual rainfall.

qualities are being identified and seed mul-
tiplication carried out to fill the nation's
needs. This is a rapid means of providing the
farmer with improved technology.
The advantage of this is that the varieties
selected have survived ecological conditions
in Botswana for several years. Selection pro-
cedures, under artificial protection from in-
sect attacks through regular insecticide
spraying, would have resulted in different
varieties emerging as top producers. Farm-
ers currently do not consider spraying a prof-
itable practice. Hence, recommending vari-
eties dependent on insecticide treatment is
inappropriate at this stage. It also should be
borne in mind that the present procedure
only identifies available cowpea lines for
use during drought. According to some
meteorologists, Southern African drought
years tend to occur in cycles of seven to ten
years. Other selection criteria must be
applied to identify varieties suitable for rela-
tively humid seasons.

Improving local cultivars for release is a
somewhat slower process. It involves
germplasm collection and evaluation fol-
lowed by breeding to incorporate missing
traits into otherwise promising material. The
first step is germplasm collection. Botswana
harbors a large, diverse genetic base of
cowpeas. Seed from more than 650 local cul-
tivars was collected, and 337 of them were
evaluated under field conditions. More than
fifty descriptors were employed to classify
the material over a wide array of maturity,
growth habit and other performance factors.
The indigenous germplasm covered the full
range of growth habit with the majority
(60%) of cultivars being erect. The growing
cycles varied widely, ranging from 64 to 196
days. The majority showed little or no pig-
mentation of the green plants but heavy
pigmentation of the flowers. Pod length was
normally distributed around a mean of
118mm with a range of 30 to 230mm. Pods of

i -_' L i r |i u. N U ri t- Ic-' i.s- hI',w rn f-U fe I D'm1 os% d riJ tid5
ER7 originally from IITA, Nigeria, which is shown here in demonstration

FIGURE 3: Others succumb to the drought
under the same conditions and are eliminated.

FIGURE 5: When moisture conditions
become inadequate to support plant
growth, certain cultural practices
such as mulching can make the
difference between some yield or
none at all. Plants in the foreground
are the same variety as those
mulched in the background.

80% of the cultivars did not shatter. Seed
length varied from 4 to 13mm. Smooth seed
coats predominated (79%). There was a
normal distribution of between 2 and 18
seeds per pod and seed weight ranged from
5 to 40g/100 seeds, with the majority weigh-
ing between 10 and 15g/100. This informa-
tion is summarized in the "Botswana
Cowpea Germplasm Catalog" published by
the Government of Botswana. Volume I of
the series is available from the Director of
Agricultural Research, P/Bag 0033,
Gaborone, Botswana. Volume II is in print.
All accessions are maintained in a cold stor-
age facility at the Department of Agricultural
Research, Sebele, Botswana. Subsamples of
many accessions have been entered in the
cowpea collections at IITA and the USDA,
The second step toward improved local
varieties is crossing with exotic ones having
desirable agronomic character. In anticipa-
tion of the project's expansion into crop
breeding activities, cowpea breeders from
IITA and SAFGRAD assisted with initiation of
a breeding program. Three or four local cul-
tivars which displayed vigorous growth
under drought conditions, desirable plant

type, high yielding ability and absence of
virus disease symptoms were crossed with
exotic varieties having very early maturity
and very high yielding capacity in their re-
gion of origin. ER7 was one of these exotic
varieties. F2 and F3 materials derived from
the crosses made during 1983 are now avail-
able for testing in Botswana. The 1984-85
field season will mark the beginning of ex-
tensive screening of breeding materials. The
search for improved varieties based on in-
digenous germplasm will be accelerated by
the addition of a breeder/pathologist and an
entomologist to the project.
The Bean/Cowpea CRSP, in collaboration
with the Botswana Department of Agricul-
tural Research in the Ministry of Agriculture,
provides research staff from Colorado State
University for development of the national
cowpea program, while young Botswanan
scientists are enrolled in graduate programs
in the United States and/or short-term pro-
fessional training elsewhere in Africa. Prepa-
ration of Host Country researchers for the
tasks ahead and the several years of joint re-
search between the Colorado and Botswana
teams secure long-term benefits both for the
country and its cowpea improvement pro-

For further information contact:
Bean/Cowpea CRSP
200 Center for International Programs
Michigan State University
East Lansing, Michigan 48824-1035
Telephone: (517) 355-4693
Telex: 810-251-0737

An international community of persons, institutions,
agencies and governments committed to collectively
strengthening health and nutrition in developing
countries by improving the availability
and utilization of beans and cowpeas

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