Response to soil ph, variability and heritability of common bean (phaseolus vulgari l) genotype for iron and zinc concentration
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Date
2019
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Sokoine University of Agriculture
Abstract
Common bean (Phaseolus vulgaris L.) is the most important food legume in the world.
In Tanzania the common bean crop is cultivated for home consumption as well as for
cash income. The objectives of this study were to determine the effect of soil pH on
levels of iron and zinc in twenty five common bean genotypes and to determine
heritability of iron and zinc using the progeny of crosses between low and high
micronutrients (Fe and Zn). An incubation experiment was performed in screen house to
adjust soil pH to levels of 5.5, 6.5 and 7.5 using hydrated lime (Ca(OH) 2 ) for four
weeks. The experimental design followed a randomized complete block design in a split
plot arrangement with three replications per treatment. Two common bean seeds were
sown at 5 cm in each pot and grow for three months before harvesting for analysis of
iron and zinc in the laboratory. Concentration of iron and zinc in leaves and seeds were
adversely affected by soil pH. The result demonstrated that soil pH can affect absorption
of micronutrients directly or indirectly by affecting the nutrients availability of common
beans genotypes. Hence assessing variability is fundamental to identify the most
important traits in common bean improvement program. Four crosses (Nua 11 × Zawadi,
Nua 11x Pesa, Nua 17 x Zawadi and Nua 17 x Pesa) using diverse parents with varied
levels of grain iron and zinc concentrations were made to study heritability for iron and
zinc . Broad sense heritability observed in Nua 11 x Zawadi was (56%) and Nua 11 x
Pesa was (76%) for concentration of iron while Nua 17 x Zawadi was (57%) and Nua 17
x Pesa was (59%) for concentration of zinc. Narrow sense heritability observed in Nua
11 x Zawadi was (65%) and Nua 11 x Pesa was (71%) for concentration of iron while
Nua 17 x Zawadi was (79%) and Nua 17 x Pesa was (63%) for concentration of iron
and zinc. This study demonstrates, there were increase of concentration of iron and zinc
in common bean genotypes at soil pH levels 6.5 and 5.5 that have potential for improvement of micronutrients in common beans and heritability of zinc and iron are
moderate to high indicating that these traits can be improved by breeders.
Description
A Dissertation 2019
Keywords
Soil ph, Common bean, Zinc concentration, Iron, genotype