Potential of genetic resources and breeding strategies for base-broadening in Beta .

Abstract

This chapter reviews topics on: the sugarbeet breeding research community; the genus Beta and its useful characters; bottlenecks to the utilization of Beta genetic resources; breeding approaches to broaden the genetic base of Beta (introgression from the primary gene pool; introgression from the tertiary gene pool; incorporation from the primary gene pool; incorporation from the secondary gene pool). The future role of gene banks in germplasm enhancement programme is also discussed.

Genetic approaches to sustainable pest management in sugar beet (Beta vulgaris)

“…In feeding experiments, AJpoly2 and PN Mono1 had less sugar reduction and were regarded as miner-tolerant varieties. Tolerance against leaf miner was also reported in Beta trigyna and B. patellaris inhibited miner spread because the larvae could not reach second pupae custodiata (reviewed by Van Geyt et al, 1990;Frese et al, 2001). …”

“…fumigant methyl bromide) and the continuous development of pesticide tolerance in several pests have prompted plant breeders to develop pest-resistant cultivars as an important part of integrated pest management systems. Since the 1980s, programmes for largescale Beta germplasm collections and multiple parameter evaluations including pest tolerance, disease resistance and productivity have been carried out in several laboratories to enable sustainable sugar beet breeding and to broaden its genetic base (Doney & Whitney, 1990;Zhang & Liu, 1998;Asher et al, 2001;Frese et al, 2001;Luterbacher et al, 2005;. Sources of resistance to pests, for example nematodes, are frequently found in wild Beta species and have been introgressed into sugar beet through interspecific hybridisation (reviewed by Savitsky, 1975;Brandes et al, 1987;Van Geyt et al, 1990;Yu, 2005;.…”

Environmental implications of gene flow from sugar beet to wild beet - current status and future research needs

“…In relation to (a), it is important that Beta plant genetic resources (gene pool) are protected from loss of diversity (Frese et al, 2001). In order to protect beet crops with relation to (b), the development and recombination of certain transgenic traits that may enhance fitness in natural wild beet habitats or develop aggressive weed beet genotypes by enhancing invasiveness should be avoided.…”

Evaluation of rhizomania-resistance segregating sequences and overall genetic diversity pattern among selected accessions of Beta and Patellifolia. Potential implications of breeding for genetic bottlenecks in terms of rhizomania resistance

“…At the same time, our results suggest that the modern sugar beet cultivars may be partially narrowed and/or altered in terms of their resistance determinants as compared to wild beet materials, which however seems an inevitable tendency, taking into account the above-mentioned wild germplasm-related obstacles on one hand and the ever-increasing demands of market competitiveness on the other. Therefore, different initiatives have been undertaken thus far to broaden the genetic base of Beta (Frese et al 2001). Apart from the impact of breeding practices, another important point contributing to discrepancies between wild and cultivated germplasms is that diverse selection pressures of native wild beet habitats favour the emergence and preferential maintenance of new advantageous alleles/polymorphisms, for instance in response to resistance-breaking viral pathotypes.…”

“…From this time on, many directed and internationally coordinated initiatives have been undertaken by research and breeding communities, especially in France and the USA, aiming not only at the introgression of selected valuable traits into the sugar beet crop, but also at broadening of its genetic base. Such an integrated approach, although requiring further selection cycles, is at the same time expected to stimulate more rational and flexible management of genetic resources in the future (Frese et al 2001). Additionally as a result of interfertile B. vulgaris coexisting in seed production areas, spontaneous outcrossings between wild and cultivated beets promote the origin of weed beets (Boudry et al 1993).…”