Estimation of Combining Ability of Maize Inbred Lines for High Plant Density Tolerance in Medium Altitudes of Kenya
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Date
2023
Authors
Ndungu, John
Henga, Silvia
Makumbi, Dan
Journal Title
Journal ISSN
Volume Title
Publisher
IPRJB
Abstract
Purpose: The primary objective of any breeding program was to
increase yields, thus superior lines based on yields are used as
parents. After parents’ selection, hybrids may not perform as
expected because the performance is influenced by the
interactions of genotypes used, which the breeder must be well
conversant with for accurate prediction of the ultimate hybrids.
Methodology: This study aimed at characterizing tropical maize
germplasm on plant density tolerance and comparing combining
abilities for grain yield on 120 hybrids obtained by crossing 24
males with 30 female lines using North Carolina design 2 (sets
option). This was done under low (53,333), medium (66,666), and
high density (88,888) plants per ha in three different zones;
Kiboko (marginal zone), Embu (transitional medium), and
Kakamega (upper medium). General combining ability (GCA) of
54 maize inbred lines was estimated and specific combining
ability (SCA) established for 120 hybrids in 6 sets of 20 each
based on family decent. They were evaluated under optimal
conditions in the 3 sites named above. Evaluation was done at
low, medium and high plant densities under study. The hybrids
were planted in a 31*8 alpha lattice design, four local commercial
varieties incorporated as checks, and the experiment replicated
twice. Data collected included various agronomical traits
associated with tolerance to high plant density. Field book
software (CIMMYT) was used to organize data and perform
preliminary analysis while SAS program (Frederick, 1999) was
used to compute analysis of variance (ANOVA) for North
Carolina design 2 (NC2).
Findings: Observation revealed increase in plant height, grain
yield, ear height, anthesis silking interval, days to 50% silking but
lead to reduction in leaf angle with increase in plant density from
53,333 to 66,666 and then to 88,888. Six hybrids were
significantly earlier than the check hybrids CKH10717, H517,
WH505 and PHB30G19 under the 3 densities. In contrast, 6
varieties were later than all the above checks for the 3 densities.
Line CKL15276 had the highest GCA effects for anthesis and
days to silking at the three plant densities and highest grain yield
at 66,666 plant density. In contrast female line CKL15303 had
the highest negative GCA effects for anthesis and days to silking
at the three plant densities revealing earliness traits. Likewise,
lines CML444, CML 436 and CKL151431 had highly significant
GCA effects for field and grain weights. The hybrid CKH 156598
had the highest significant SCA effects for grain yield at 66,666
plant density and for field weight at the three plant densities.
Unique Contribution to Theory, Practice and Policy: The
study was informed by Diallel Crossing Theory and conducting
systematic field trials, researchers can gain insights into the
genetic effects of combining different maize inbred lines and
identify potential candidates for developing maize varieties with
improved high plant density tolerance in the specified region.
This reveals presence of superior alleles and desirable SCA
effects and thus can be utilized as parents in hybrid formation and
further breeding work. The study also recommends that support
should be garnered from relevant government agencies and
policymakers to allocate resources for the collaborative network's
activities. Advocate for policies that promote research and
development in maize breeding for high plant density tolerance.
Description
Article
Keywords
Maize, Combining Ability, Superior Alleles, Plant Densities
Citation
Ndungu, J., Danga, B., Henga, S., & Makumbi, D. (2023). Estimation of Combining Ability of Maize Inbred Lines for High Plant Density Tolerance in Medium Altitudes of Kenya. International Journal of Agriculture, 8(2), 54–79. https://doi.org/10.47604/ija.2066