Novel inflorescence architecture in gamma radiation-induced faba bean mutant populations

Conventional and Molecular Breeding Tools for Accelerating Genetic Gain in Faba Bean (Vicia Faba L.)

Faba bean is a cool-season grain legume crop, which is grown worldwide for food and feed. Despite a decrease in area under faba bean in the past, the interest in growing faba bean is increasing globally due to its high seed protein content and its excellent ecological service. The crop is, however, exposed to diverse biotic and abiotic stresses causing unstable, low grain yield. Although, sources of resistance to main diseases, such as ascochyta blight (Ascochyta fabae Speg.), rust (Uromyces viciae-fabae (Pers.) Schroet.), chocolate spot (Botrytis fabae Sard.) and gall disease (Physioderma viciae), have been identified, their resistance is only partial and cannot prevent grain yield losses without agronomical practices. Tightly associated DNA markers for host plant resistance genes are needed to enhance the level of resistance. Less progress has been made for abiotic stresses. Different breeding methods are proposed, but until now line breeding, based on the pedigree method, is the dominant practice in breeding programs. Nonetheless, the low seed multiplication coefficient and the requirement for growing under insect-proof enclosures to avoid outcrossing hampers breeding, along with the lack of tools such as double haploid system and cytoplasmic male sterility. This reduces breeding population size and speed of breeding hence the chances of capturing rare combinations of favorable alleles. Availability and use of the DNA markers such as vicine-convicine (vc -) and herbicide tolerance in breeding programs have encouraged breeders and given confidence in marker assisted selection. Closely linked QTL for several biotic and abiotic stress tolerance are available and their verification and conversion in breeder friendly platform will enhance the selection process. Recently, genomic selection and speed breeding techniques together with genomics have come within reach to accelerate the genetic gains in faba bean. Advancements in genomic resources with other breeding tools, methods and platforms will enable to accelerate the breeding process for enhancing genetic gain in this species.

AFLP-Based Analysis of Variation and Population Structure in Mutagenesis Induced Faba Bean

Genetic diversity enrichment is urgently necessary to develop climate-resilient faba bean cultivars. The present study aimed to measure the enrichment of genetic diversity and changes in the population structure of faba bean, following induced mutagenesis. 120 samples, including 116 M2 mutant plants, generated by exposing the ILB4347 accession to four mutagen treatments (25 and 50 Gray gamma radiation and 0.01%, and 0.05% diethyl sulfate) and four reference genotypes were characterized using 11 amplified fragment length polymorphism (AFLP) primer combinations. The AFLP markers generated 1687 polymorphic alleles, including 756 alleles (45%) that were detected infrequently (f ≤ 0.1). The total allele count of the mutant plants ranged from 117 to 545. We observed a wide range of banding patterns and counts among the mutant plants, showing the high genetic diversity induced by mutation. Mutations also changed the population structure, by altering 31.78% of the total membership coefficient (Q). Although mutations changed the population structure, Nei’s genetic distance showed that the mutant population remained closely related to its control parent. This is the first report examining genetic diversity and population changes in faba bean mutant populations and, thus, could facilitate the application of induced mutagenesis during faba bean breeding.