TITLE:
Line × Tester Analysis of Tropical High Land Maize (Zea mays L.) Inbred Lines Top Crossed with Three East African Maize Populations
AUTHORS:
Teshale Assefa, Habtamu Zeleke, Thumasi Afriye, Paul Otyama
KEYWORDS:
Maize, Line, Tester, Combing Ability, Crosses
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.8 No.2,
January
20,
2017
ABSTRACT: Maize breeding efforts to generate high yielding and
adaptive cultivars have recently been given emphasis by national maize breeding
program. In Ethiopia, the maize production system is mainly dominated by
subsistence farmers where their production
is below average. The objectives of this study were to determine the
combining ability between lines and testers, and to evaluate the performance of
crosses (hybrids) and parents for grain yield and yield component traits.
Twenty-seven inbred lines were generated by crossing nine female lines (L1-L9)
and three male testers (T1-T3) using line × tester mating system at International
Maize and Wheat Improvement Center (CIMMYT), East African high land maize
improvement program. The inbred lines along with parents were evaluated in
randomized complete block design with two replications at three locations
(Ambo, Kulumsa and Haramaya). Significant differences were observed among genotypes
for all ten traits considered. Eight crosses (L1 × T2, L1 × T3, L3 × T3, L8 ×
T1, L4 × T2, L9 × T1, L2 × T1, and L2 × T2) had higher yield performance
compared to other crosses across environments. Significant mean square
differences were found across locations for general combining ability (GCA) due
to lines for all traits except for number of kernel rows per ear, whereas GCA
due to testers were significant only for grain yield, ear length and 1000-seed
weight. Significant mean square due to GCA × Loc (both for lines and testers)
was found for days to maturity (38.71*), 1000-seed weight (4582.36**) and grain
yield (2756777**), while significant SCA × Loc interaction was found for all
traits except number of kernel rows per ear (1.07), ear length (0.79) and ear
diameter (0.12), suggesting that the importance of additive and non-additive
gene effects in controlling these characters.