INHERITANCE OF Bt TRANSGENE CONTROLLING THE LEGUME POD BORER (Maruca vitrata [Geyer]) IN COWPEA(Vigna unguiculata L. Walp)
INHERITANCE OF Bt TRANSGENE CONTROLLING THE LEGUME POD BORER (Maruca vitrata [Geyer]) IN COWPEA(Vigna unguiculata L. Walp)
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Date
2012-12
Authors
MOHAMMED, BABA SABA
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Abstract
The inheritance of Bt transgene controlling the legume pod borer [Maruca vitrata (Geyer)]
in cowpea (Vigna unguiculata L. Walp.) was studied using two transgenic lines namely;
709 and 711. These were crossed to three non-transgenic lines viz; IT97K-499-35, IT93K-
693-2 and IT86D-1010 to produce six hybrids. Field trial was conducted at confined field
trial site (CFT), Samaru, involving F1, F2, backcross populations and the five parental
materials. The study was undertaken to understand the mode of inheritance, segregation
and stability of Cry1Ab gene in different cowpea genetic backgrounds. The results showed
3:1 and 1:1 segregation for F2 and first backcross generations respectively. These
demonstrated the existence of Mendelian inheritance of Cry1Ab gene in cowpea genome.
Cry1Ab gene was inherited as a single dominant gene and segregates in the Mendelian
fashion. Therefore, classical cross and backcross can introgress the Cry1Ab Maruca
resistant gene from the transgenics into conventional cowpea varieties. Quantitative
analysis for Cry1Ab gene resistance with the use of artificial infestation showed that the
inheritance of Cry1Ab gene was governed by a dominant gene action. The performance of
the transgenic lines and their hybrids in comparison with the non-transgenic parents
regarding some key paramters were conducted. The transgenics and the hybrids did not
sustain pod damage due to Maruca feeding while the non-transgenic genotypes sustained
various degrees of pod damage as a result of feeding activities by the Maruca. In addition,
the impact of genetic transformation of cowpea on the expression of some morphological
traits of the transgenic lines were investigated. In the present study, comparison made
between the cowpea transgenic line 709 and original parental type (IT86D-1010) showed
non-significant differences in all the parameters compared while, comparison made
between cowpea transgenic line 711 showed highly significant differences for days to first
flowering, days to first pod maturity and plant height. However, the phenotypic data
showed no pattern of changes that would support the hypothesis that the introduction of
Cry1Ab gene had any unintended impact on the productive performance of cowpea plants,
besides conferring resistance to Maruca pest.
Description
A THESIS SUBMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES,
AHMADU BELLO UNIVERSITY, IN PARTIAL FULFILLMENT FOR THE
AWARD OF MASTER OF SCIENCE IN PLANT BREEDING
DEPARTMENT OF PLANT SCIENCE
FACULTY OF AGRICULTURE
AHMADU BELLO UNIVERSITY, ZARIA
DECEMBER, 2012
Keywords
INHERITANCE,, Bt TRANSGENE, LEGUME POD BORER, (Maruca vitrata [Geyer]), COWPEA,, Vigna unguiculata L. Walp