Mutagenesis and breeding for disease resistance in capsicum

The principal diseases, for which no sources have so far been found within the cultivars of Capsicum annuum in Italy, are caused by Verticillium dahliae, Phytophthora capsici and cucumber mosaic virus (CMV). The wild species C. pendulum, C. frutescens, C. chinense, C. chacoense, C. pubescens and C. eximium were analysed to find out if the sources for resistance to the three diseases are available. It was observed that particularly the species C. frutescens and C. chinense had good sources of resistance to V. dahliae and Ph. capsici. However, the occurrence of reproductive barriers between the wild and cultivated species appears to be a problem for the transfer of disease-resistant genes. For CMV, none of the wild species showed good resistance; so in this case a screening technique was set up using mutagenic agents to isolate resistant types in the prominent agronomic cultivars of C. annuum. Also, for V. dahliae and Ph. capsici, mutation screening techniques were set up to induce disease resistance character directly in the cultivars of C. annuum, without causing any changes in the most important agronomic characters of the cultivars. (author)