Advances in Plant Breeding Strategies: Legumes by Unknown

Author:Unknown
Language: eng
Format: epub
ISBN: 9783030234003
Publisher: Springer International Publishing

7.3.2 Germplasm Conservation

The in situ conservation and evaluation of any plant species depend on its reproductive system. Faba bean is partially cross-pollinated by insects. The reproductive system in the dominant population follows a pattern of interbreeding. The cross-pollination rate varies greatly depending on genotype and geographical location; pollination mainly depends on climatic factors and insect pollinators in the field. Most of the experimental data on the gene flow of faba bean indicate that the conservation and reproduction of faba bean genetic resources must exclude the involvement of insect pollinators. Using insect-proof cages is an effective way to conserve Vicia faba genetic resources. When a great number of faba bean genetic resources need to be multiplied and the quantity of each seed sample is often very large, the insect-proof cage is no longer applicable, because of high cost, difficult operation and management, and will also lead to a decline of yield caused by inbreeding recession. The development of germplasm conservation techniques of faba bean depends on maintaining appropriate gene flow between different faba bean accessions during multiplication practices in the field; appropriate isolation crops are needed. According to our field tests in faba bean breeding, in order to reduce gene flow between different accessions or genotypes, the use of a 3-meter isolation distance and biological barrier (rapeseed or rye) can reduce the hybridization between adjacent accessions by more than 95%. For large numbers of faba beans to be planted, the field must be kept at least 50–100 m away from other faba bean fields to maintain seed purity (Bao et al. 2016).

The genetic resources of ex situ collections of faba bean are mainly local landraces and mass selections from landraces, open-pollinated populations, synthetics, inbred lines and hybrids (Duc et al. 2010). The main practice for long-term conservation of ex situ collections is to preserve the original dry seeds and their purified dry seeds in cryogenic and ultra-cryogenic cold storage with different specifications and construction forms (Bao et al. 2016). Faba bean genetic resources are usually conserved in gene banks at −20 °C to −18 °C for long-term strategic safe storage (Zheng et al. 1997). For the medium-term repository, a storage temperature of around 5 °Cis used by the National Genbank of the CAAS (Chinese Academy of Agricultural Sciences, Beijing, China), USDA and ICARDA (Bao et al. 2016).

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