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Analyses of moisture
deficit grain yield loss in drought tolerant maize (Zea
mays L.) germplasm accessions and its relationship with
field performance
G. Olaoye*, O. B. Bello,
A. Y. Abubakar, L. S. Olayiwola and O. A. Adesina
Department
of Agronomy, University of Ilorin, P. M. B. 1515, Ilorin,
Nigeria.
*Corresponding author. E-mail:
debolaoye@yahoo.com.
Accepted 15
May, 2009 |
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Development of drought tolerant maize cultivars is
prerequisite to achieving stable grain yield in
drought–prone ecologies of Nigeria’s Guinea savanna.
However, success has been limited mainly due to lack of
maize genotypes that show clear differences in response to
well defined moisture deficit condition. Two sets of drought
tolerant (DT) maize germplasm were evaluated under
screenhouse and field conditions between 1999 and 2002. In
the screenhouse study, performances of the genotypes were
compared under well-watered condition and moisture deficit
imposed at different growth stages. Under field conditions,
the first set comprising 11 accessions along with a check
were evaluated for 4 growing seasons while the second set
which comprised 3 DT varieties were evaluated along with 2
check varieties using monthly plantings between April and
August of 2001 and 2002, respectively. In the first set,
post anthesis moisture deficit significantly reduced grain
yield by 25 to 73.5% in the open pollinated varieties (OPVs)
and by 20 to 64% in the hybrids. Grain yield under field
conditions ranged from 2.48 to 3.49, 2.82 to 3.73 and 3.58
to 4.76 tons/ha-1 for 1999, 2000 and 2001 full
growing seasons, respectively, and 2.03 to 2.50 tons/ha-1
for 2000 late growing season. In the second set, pre and
post anthesis moisture deficits reduced grain yield by 77.6
and 95.8%, respectively, of well watered condition while in
the field, grain yields in the genotypes were highest for
plantings made in April and July (1.90 - 2.5 t/ha), lowest
for August (0.7 -1.8 t/ha) when moisture deficit coincided
with reproductive phase. Yield stability exhibited under
moisture deficit and on the field by 8522-2, Oba super 2 and
AK9943-DMRSR in the first set as well as DT-SR-Y C0 and
DT-SR-W C0 in the second set, indicates their suitability
either as cultivars per se or as potential source of
DT alleles for development of DT maize varieties for
Nigeria’s savanna ecologies.
Key
words:
Drought tolerance, moisture
deficit, germplasm accessions, planting dates, grain yield. |
