**7. Breeding methods**

**Introduction:** Collections of related materials from other countries, particularly from areas where the pathogen and host species may have co-evolved, sometimes provide rich pools of resistance genes [22]. In vegetable peas, early introductions from Europe and USA were found quite successful and popular in India. These included Arkel (early maturing, dwarf type, introduction from England in 1970s) and Bonneville (main season, late maturing, tall type, introduction from USA in 1970s). These introductions were obtained at IARI, New Delhi and were released for commercial cultivation after preliminary evaluation. Early Badger a dwarf, wrinkled seeded variety introduced from USA has resistance to *Fusarium* wilt.

### **8. Utilization of wild species**

The major bottleneck in the resistance breeding programme is the lack of resistant source in the cultivated germplasm. This has necessitated breeders to search resistance for genes in wild species that are taxonomically related and compatible. The use of wild forms in breeding crop plants, particularly to obtain vigor and

#### *Breeding Approaches for Biotic Stress Resistance in Vegetables DOI: http://dx.doi.org/10.5772/intechopen.94983*

resistance hasbeen well recognized [1]. In vegetables, several experiments involving wild species have been carried out. Selection of a genotype with high yield and resistance reduces the yield loss on one hand and increases the availability of the produce to market which is fairly free from residue on the other hand. Generally the source of genes for resistance are (i) provided by the variability within the crop species, (i) varieties from original home of insect, (ii) varieties from centres of great insect occurrence, (iii) varieties from areas of greatest morphological diversity.

In muskmelon gene for resistance is not available in the cultivated species, but *Cucumis africanus* was found to be fairly resistant to fruit fly. Similarly, *Cucumis heptadactylis* was resistant to red pumpkin beetle. An attempt to incorporate the resistance to shoot and fruit borer in the cultivated egg plant genotypes was made in interspecific hybridprogenies of the cross *S. melongena* x *Solanum viarum* and evaluating the direct segregating progenies of such interspecific crosses so as to identify recombinant inbred plants with high yield and shoot and fruit borer resistance. The data recorded from direct F9 generation derivatives of EP 65 x *Solanumviarum* were utilized to study thoroughly and three progenies each out of thirty in F9 generations were selected for further studies. All these selected progenies have performed very well with respect to shoot and fruit borer resistance. From this evaluation studytwo hybrid derivatives were selected and designated as HD 1 and HD 2. The progenies of the culture HD1 recorded minimum shoot (7.69%) and fruit borer infestation (6.67%). The HD2 progenies recorded the minimum shoot (9.09%) and fruit borer infestation as 6.85%. The selected progenies *viz*., HD 1 and HD 2 showed profuse flowering and fruiting and also cluster bearing habit. The color of the fruit was bright purple while the fruit surface was smooth, glossy along with tightly packed seeds in its flesh which again act as physical barrier for mandibles of fruit borer to chew and bore into the flesh of fruits [18].

Tomato is a self pollinated crop, which is a high demand vegetable crop. The wild species are reservoir of important genes in tomato. *Solanum pimpinellifolium* is the only red-fruited wild species of tomato. Because of the close phylogenetic relationship between the two species, there is little or no difficulty in initial crosses in subsequent generations of pre-breeding and breeding activities. Nineteen accessions from seven *Lycopersicon* species were bio assayed for their resistance to *Heliothis armigera* by [23]. It was found that among the various *Lycopersicon spp*. bioassayed, accessions of *L. hirsutum f. glabratum* is most potential for breeding *H. armigera* resistant cultivars.

Wilt, little leaf and phomopsis blight are the serious diseases of brinjal. *Solanum incanum* is resistant to *Fusarium* wilt*.* In humid tropical areas brinjal is highly infected with bacterial wilt. Wild species of *Solanum viz., S. torvum, S. xanthocarpum, S. nigrum*, and *S. sisymbriifolium* are resistant [24]. The wild species *Solanum viarum* showed no infection and was immune, whereas the species *S. incanum* and *S. sisymbrifolium* were resistant to little leaf disease.

Pinheiro et al. [25] conducted two assays, to evaluate the resistance to root knot nematode, *M. incognita* race 1 in *Citrullus lanatus* cv. *Citroides*, *Lagenaria vulgaris*, *Sicana odorifera*, *Cucurbita facifolia, Cucurbita moschata*, *Cucurbita moschata* x *Cucurbita maxima*, *Luffa* sp., *Cucumis melo* and *Cucumis metuliferus* accessions. The results revealed that three accessions of *Cucumis metuliferus* ('Kino') were resistant to *M. incognita* race 1 in the first experiment. In the second experiment conducted to evaluate the reaction to nematode *M. incognita* race 1, *M. javanica* and *M. enterolobii* all the seedlings in pots were inoculated with 2nd stage (J2) juveniles and 5000 eggs of each *Meloidogyne* species. The observations on egg mass index (IMO), gall index (IG), number of eggs per gram of root (NEGR) and reproduction factor (RF) was observed on 53 and 84 days after inoculation, respectively. The melon *Cucumis metuliferus* was resistant to root-knot nematode.
