Genetic Inheritance of Horticultural Traits in Faba Bean (Vicia faba L.)
Date
2019-11-04
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
0000-0003-0179-1169
Type
Thesis
Degree Level
Masters
Abstract
Faba bean (Vicia faba) has a relatively unexplored diversity in comparison to other legume crops. The large genome (13Gb), multiple centres of origin, and multiple domestication events resulted in vast diversity and many unexplored characteristics. Faba bean is both a grain legume and a vegetable, with its popularity ranging from being a common household food (Mediterranean and Asia) to being nearly unknown (North America). The horticulturally valuable traits of faba bean are very poorly researched. The main objective of this study was to determine the inheritance of the important characteristics for horticultural-type faba bean. Understanding these traits will aid in the expansion of faba bean into the horticulture market (ornamental and vegetable). Three traits were observed during this study to determine their inheritance: flower colour, plant height and branching. A selected diallel crossing block was performed and the subsequent F2 populations were phenotyped. The genetic sources for flower colour studies were P47-1 (red) and Gelber (yellow). Pearson chi-square goodness of fit tests were used to determine if the segregating F2 populations fit the hypotheses for a 15:1 ratio of red: non-red flower and 3:1 for brown: yellow wing spot. The chi- square value confirmed that red flower phenotype is controlled by two recessive genes and that the yellow wing spot is controlled by a single recessive gene (p>0.05). However, the inheritance of flower colour in faba bean is more complex than could be explained with these two hypotheses. To determine the inheritance of plant architectural characteristics, populations were developed using two different sources of dwarfism (NV153 and Rinrei) and one source of a highly branched phenotype (IG11476). F2 populations segregating for both sources of dwarfism were examined using a chi-square test. Populations segregating for both sources of dwarfism were tested for a single recessive gene model (3:1). Both dwarfs in this study fit this model based on visual characterisation, but only NV153 type dwarfs were true dwarfs. Rinrei type dwarf plants are more accurately described as slow growing plants. These plant types continued to grow throughout the season, resulting in non-significant height and internode data for dwarfism. The gene that causes the Rinrei type ‘slow growth’, does fit a 3:1 single recessive gene model and is pleotropic. The dwarf and slow growth gene are also additive and resulted in an extreme form of dwarfism at a ratio of 15:1. The highly branched trait did not fit into discrete categories and had a normal distribution characteristic of quantitatively inherited traits. The relationship between flower colour and dwarfism with vicine-convicine was also analyzed by creating F2 populations that segregated for some of the horticulturally valuable traits and for the low vicine-convicine gene. Linkage was determined by chi-square analysis within each phenotypic class for the –vc gene that is known to be controlled by a single recessive gene and is not linked to red flower colour, yellow wing spot flower colour or Rinrei’s ‘slow growth’ gene.
Description
Keywords
Faba bean, Horticulture, Genetics
Citation
Degree
Master of Science (M.Sc.)
Department
Plant Sciences
Program
Plant Sciences