5.4.9
RESISTANCE TO FUSARIUM HEAD BLIGHT IN WINTER TRITICALE SOMACLONES GENERATED FROM DON-SELECTED AND UNSELECTED CALLI

T GORAL1, J PERKOWSKI2, J STACHOWIAK2, A GLOWACKA2 and E ARSENIUK1

1Department of Plant Pathology, Plant Breeding and Acclimatization Institute, Radzikow, 05-870 Blonie, Poland; 2Department of Chemistry, Agricultural University, 60-625 Poznan, Poland

Background and objectives
Deoxynivalenol (DON) is one of the main toxins produced by Fusarium species infecting small grain cereals, e.g. F. graminearum and F. culmorum. It is a mycotoxin very frequently occurring in grain and is harmful to host plants as well as to animals and humans. Its role in pathogenesis is not clear thus far; however, there are reports that ability to produce DON significantly influences the pathogenicity of Fusarium isolates [1]. The aim of the study was to find if selection of winter triticale calli with DON could improve Fusarium resistance of regenerated plants. Reaction of selected somaclones was compared to reaction of unselected somaclones and parental cultivars to identify types of improved resistance and tolerance.

Materials and methods
In the field experiment, resistance of 32 somaclones and two parental cultivars (Moniko, Presto) of winter triticale was tested. Somaclonal lines consisted of somaclones obtained using the immature embryo technique without selection (16 for Presto, 10 for Moniko) and selected with DON (one for Presto, five for Moniko). Isolates of Fusarium culmorum were used to produce inoculum. Heads of triticale plants were inoculated by spraying with a spore suspension at mid-anthesis growth stage. This was done four times, depending on the mid-anthesis time of different somaclones. The disease was rated first at about 14 days after the last inoculation. Four ratings were done at 7-day intervals. Fusarium head blight (FHB) severity was scored on the basis of the mean percentage of blighted spikelets per infected head and the percentage of infected heads per plot. After harvest, reductions of yield components were determined. Deoxynivalenol concentration in kernels was analysed using GCMS.

Results and conclusions
A wide range of variability was found for all parameters among selected as well as unselected somaclones. All Moniko-derived selected somaclones were slightly more susceptible (FHB rating) than the original cultivar, but for yield reduction somaclones selected with DON were significantly improved. However, results indicated that in vitro selection with DON can significantly improve resistance or tolerance to FHB. Our conclusions are therefore contrary to the results of Ahmed et al. [2] obtained with wheat.

References
1. Mirocha CJ, Yu H, Evans CK et al.,1997. Cereal Research Communications 25, 309-314.
2. Ahmed KZ, Mesterhazy A, Sagi F, 1996. In Bajaj YPS, ed., Somaclonal Variation in Crop Improvement 11. Springer Verlag, Germany, pp. 3-19.