Developing top cross maize (zea mays l.) hybrids tolerant against maize streak virus (msv) disease for the Eastern zone ecologies
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Date
2014
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Sokoine University of Agriculture
Abstract
Maize production in smallholder farming community has remained low due to a
number of constraints which include biotic and abiotic. Among biotic constraints,
Maize streak virus (MSV) disease is one of the major causes of low yield if not
controlled. Genetic resistance appears to be the best economical option to control
MSV and it is readily adopted as method for smallholder farmers, because of less
cost and environmentally friendly. The main objective of this study was to produce
high yielding top cross maize hybrids which are tolerant to MSV disease for growing
in the Eastern ecologies of Tanzania. Staha (female) and fourteen inbred lines (male)
were used to produce top cross hybrid genotypes. Evaluation for MSV resistance was
done under natural infection. RCBD replicated three times was used in three selected
MSV hot spots of Eastern areas of Tanzania. Fourteen top cross hybrid genotypes
and two checks were used. Highly significant variation (P - 0.001) was found
among the genotypes for MSV and grain yield. Dak0127, Dak0122, Dak0125 and
Dak0124 genotypes were identified as the best materials for yield and tolerant to
MSV disease while Dak0123, Dak01211 and Dak01210 genotypes were not good for
locations having high MSV disease pressure. Significant and positive correlations
between yield and plant height, ear length, hundred seed weight and ears/plant were
observed. Path coefficient analysis indicated importance of the same variables
through their direct contribution on grain yield. High heritability was observed for
grain yield, ear length, number of rows/ear, grains/ear and grains/row, MSV disease
incidence and severity, ear height, ears/plant, ear circumference, plant height. Based
on correlation analysis earlier silking should be used for increased yield at theseiii
locations. High yielding MSV disease tolerant top cross genotypes which were
identified are recommended for more seasons’ evaluation for identifying genotypes
to replace existing inferior cultivars.
Description
Dissertation
Keywords
Maize production, Maize streak virus, Eastern Zone