Plant Breeding and Acclimatization Institute, Radzikow, 05-870 Bionie, Poland

Background and objectives
Numerous reports from Europe indicate that lability of yield is observed in faba bean. Major yield reducing factors are diseases, pests, and environmental stresses [3, 5]. Ascochyta blight caused by Ascochyta fabae Speg., and chocolate spot caused by Botrytis fabae Sard., are diseases commonly occurring in faba bean in Poland [4]. Recently several breeding programs have concentrated on developing resistant or tolerant cultivars [1, 2, 4]. The introduction of resistant cultivars could all improve the stability of yield. The objectives of this study were to investigate the variability of resistance to A. fabae and to B. fabae in different faba bean strains, and to develop faba bean lines resistant to both pathogens.

Materials and methods
Research on development of sources of resistance to A. fabae and B. fabae in faba bean has been conducted for seven years (1991-97) at IHAR Radzikow, Poland. The field experiments with Polish faba bean breeding material were carried out. The reaction of the indeterminate growth habit and the terminal inflorescence type of faba bean accessions to inoculation with A. fabae or B. fabae was investigated. Also the genetic variation for resistance of the accessions were studied. During screening seasons, disease severity of individual plants has been estimated and plants showing resistance to A. fabae or B. fabae have been selected. Additional criterions of choice of plants were: no symptoms of infection with other pathogens (fungi, viruses and bacteria), high yield, favourable morphological characters. Progenies of selected resistant plants and their following generations were tested in the field under pressure of artificial infection with fungus A. fabae or B. fabae. The investigated plants were grown in tents for isolation from bees. Criteria for the selection of plants were the same as in the case of resistance screening.

Results and conclusions
Severity of ascochyta blight was higher than severity of chocolate spot in the faba bean accessions tested. Significant variability of resistance was observed among both the indeterminate growth habit and the terminal inflorescence of faba bean types. However, the range of variability of resistance of faba bean accessions to A. fabae was greater than to B. fabae, regardless of morphological type [6]. The spectrum of variability among plants within entries was wide and this enabled positive selection for resistance in faba bean. During the seven years of field screening faba bean plants resistant to A. fabae were selected: 125 of indeterminate growth habit and 39 of terminal inflorescence type, and faba bean plants resistant to B. fabae were selected: 15 of indeterminate growth habit and 29 of terminal inflorescence type. This study resulted in the development of faba bean lines with resistance to A. fabae and/or B. fabae. The developed faba bean inbred lines, 210 of indeterminate growing habit and 61 of terminal inflorescence type, were delivered to Polish breeders. The research was carried out within the resistance breeding programme of faba bean in co-operation with five Polish Breeding Stations.

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