Browsing by Author "OSAKWE, Obiora Joseph"

Now showing 1 - 2 of 2
  • No Thumbnail Available
    ItemMetadata only
    Inheritance Pattern of Bean Common Mosaic Virus (BCMV) Resistance Gene Using Marker Assisted Selection and of Seed Coat Colour in Cowpea
    (Bells University of Technology, 2023-05) OSAKWE, Obiora Joseph; Dr K. E. Ogunsola
    Cowpea (Vigna unguiculata (L.) Walp.) is one of the most important grain legume crops in sub-Saharan Africa. Blackeye cowpea mosaic strain of the bean common mosaic virus (BCMV-BICM) causes mosaic infections that reduce the yield of cowpea. Planting resistant varieties is the most effective control method but complex nature of disease resistance makes identification of resistant and susceptible plants cumbersome through conventional screening techniques. The use of Marker Assisted Selection (MAS) is more effective for crop genetic improvement. Seed coat colour is also an important trait in cowpea preference by consumers. Knowledge of the mode of inheritance of viral resistance and seed colour is crucial in developing improved cowpea varieties. Inheritance of seed coat colour and resistance to BMV-BICM using MAS, was investigated using two improved cowpea breeding lines. Cowpea resistant (IT98K-1092-1) and susceptible (Ife brown) varieties obtained from the International Institute of Tropical Agriculture (ITA), Ibadan and molecular markers (M15, M80, M135 and Y96) obtained from Inqaba biotech, Ibadan were used. Crosses were made between the BCMV resistant (back seed) and susceptible (brown seed colour) varieties. The F1 seeds were advanced to F2. Genomic DNA of parent lines and F1 were extracted. MAS was used to determine the pattern of inheritance of virus resistance and Chi square test of the colour segregation of F2 generations was used in investigating the inheritance of seed colour. Data on morphological traits were also taken. There were no significant differences (p=0.01) between the two parental lines and between F1 and F2 generations in the number of seeds/pod, pod length (cm), seed weight, seed/plant, pod no/plant, seed number/plant, and germination percentage. However, these parameters were significantly higher in the parental lines than F1 and F2 generations except for germination%. Similarity in growth and yield parameters in both direct and reciprocal crosses indicated compatibility and absence of maternal or cytoplasmic effect in the cowpea varieties. Inheritance of seed coat colour showed all F1 plants to be brown which indicated dominance of brown colour and 45 brown and 10 black seeds in the F2 generation. This segregation fitted significantly to the expected Mendelian ratio of 3:1 brown to black colour, indicating a single gene or monogenic inheritance of seed coat colour. The observed variation in seed colour from brown to dark brown to black also suggest the possibility of a polygenic inheritance of seed coat colour. Only M80 marker amplified the BCMV resistance gene which was amplified in the resistant variety. MAS showed that all F1 plants had no amplification of the resistant gene which implies that the mode of inheritance of the BCMV-BICM resistance is recessive in the cowpea variety. The monogenic dominance of the brown seed coat colour and the recessively inherited BCMV-BICM resistance in cowpea provide important information for breeding virus resistant and more preferred brown seed coloration in cowpea.
  • No Thumbnail Available
    ItemMetadata only
    Inheritance Pattern of Bean Common Mosaic Virus(BCMV) Resistance Gene Using Marker Assisted Selection and of Seed Coat Colour in Cowpea
    (Bells University of Technology, 2023-05-21) OSAKWE, Obiora Joseph; Dr. K. E. Ogunsola
    Cowpea (Vigna unguiculata (L.) Walp) is one of the most important grain legume crops in sub-Saharan African. Blackeye cowpea mosaic strain of the bean common mosaic virus (BCMV-BICM) causes mosaic infections that reduces the yield of cowpea Planting resistant varieties is the most effective control method but complex nature of disease resistance makes identification of resistant and susceptible plants cumbersome through conventional screening techniques .The use of marker Assisted selection (MAS) is more effective for crops genetic improvement. Seed coat colour is also an important trait in cowpea preference by consumers. Knowledge of the mode inheritance of viral resistance and seed colour are crucial in developing improved cowpea varieties. Inheritance of seed coat color and resistance to BCMV-BICM using MAS, was investigated using two improved cowpea breeding lines. Cowpea resistant (IT98K-1092-1) and susceptible (Ife-brown) varieties obtained from the international institution of Tropical agricultural (IITA), Ibadan were used. Crosses were made between the BCMV resistant (back seed) and susceptible (brown seed color) varieties. The F1 seed were advanced to F2. Genomic DNA of parent lines and F1 were extracted. MAS was used to determine the pattern of inheritance of virus resistance and chi square test of the colour segregation of F2 generations was used in investigating the inheritance of seed color. Data on morphology traits were also taken. There were no significant differences (p=0.01) between the two parental lines and between F1 and F2generations in the number of seed\pods, pod length (cm), seed weight, seed\plant, pod no\plant, seed number\plant, and germination percentage.