*5.4.2 Polyploidy breeding*

Polyploid can be induced due to aberration in cell division. This may occur both in the mitosis as well as in meiosis. This method can be used successfully in vegetable breeding as a means of enhancing nutraceuticals and colors in vegetables. Tetraploids in radish, pumpkin, and watermelon are highly productive and have improved quality. Zhang *et al*. [8] developed tetraploid muskmelon which is rich in vitamin C which is higher than those in the diploid fruit.

#### *5.4.3 Haploidy breeding*

The development of haploids in a number of plant species is now recognized as the most rapid route to the achievement of homozygosity and production of pure lines. Currently, little breeding effort is going on for improvement of *brassica* for nutraceutical species and as indicated, there are very few successful double haploid protocols.

#### **5.5 Biotechnological approaches**

### *5.5.1 Molecular markers and marker assisted selection (MAS)*

Molecular markers such as RAPD, ISSR, SSR, SCAR, CAPS are used to study linkage with gene(s) responsible for high neutraceuticals, bioactive compounds and edible colors using mapping population. Of late, use of SNP marker is becoming more common. In Marker Assited Selection, a marker (morphological, biochemical or DNA) is used for indirect selection of a trait of interest. The mapping populations such as Near Isogenic Lines (NILs), Recombinant Inbred Lines (RILs) are used to identify the molecular markers linked to genes of interest. Ripley and Roslinsky [9] identified an ISSR Marker for 2 propenyl glucosinolate content in *Brassica.*

### *5.5.2 Quantitative trait loci (QTL) analysis*

QTL analysis is the study of the alleles that occur in a locus and the phenotypes. Most traits of interest are governed by more than one gene, defining and studying the entire locus of genes related to a trait gives hope of understanding the effect genotype of an individual. The advent of molecular maps and the derived quantitative trait locus (QTL) mapping technology has provided strong evidence that despite the inferior phenotype, exotic germplasm is likely to contain QTLs that can increase the quality of elite breeding lines. Bin 3-C has previously been described as harboring a single gene mutation *r* yellow flesh in tomato [10].

#### *5.5.3 Advanced backcross QTL analysis*

The AB-QTL strategy has so for been tested in tomato and pepper. The most extensive experiments have been conducted in tomato, where populations involving crosses with five wild *Lycopersicon* species have been genotyped and field tested in a number of locations around the world for numerous traits important for the tomato processing industry. Through the application of marker and phenotypic analysis of segregating generations of the cultivated tomato and wild *Lycopersicon* species, QTLs for improved fruit color had been revealed. QTLs that improve fruit color originating from red-fruited (*S.pimpinellifolium*) and green fruited (S*.habrochaites, S parviflorum*) wild relatives had been detected in segregating populations of crosses of these species and the cultivated tomato. Quantitative trait loci associated with carotenoids and tomato fruit color using introgression populations of *S.pennellii*, *S peruvianum* and *S. habrochaites* have been described by [11].

**95**

*Breeding Vegetables for Nutritional Security DOI: http://dx.doi.org/10.5772/intechopen.95349*

*5.5.4 Introgression line (IL) libraries*

consumers.

for the variation of the tomato red fruit color.

IL libraries contain homogenous genetic backgrounds, only differing from one another by the introgressed donor segment. A tomato introgression line population that combines single chromosomal segments introgrossed from the wild, green fruited species *Solanum pennellii* in the background of the domesticated tomato, *Solanum lycopersicum* was used to identify QTL for nutritional and antioxidant contents. Liu *et al.* [12] applied the candidate gene approach to link sequences that have known functional roles in carotenoid biosynthesis to QTLs that are responsible

Marker assisted backcross breeding has been used successfully to incorporate genes or QTL for both qualitative and quantitative traits in a number of crop species especially tomato, cucumber, potato, in some cases leading to the development of improved cultivars. Of late Indian cauliflowers are being introgressed with semidominant mutant *Or* gene to enhance their betacarotene content in an attempt to tackle malnutrition problem by making diverse beta- carotene rich food available to

Interspecific crosses with wild species transferred the ability to produce small quantities of anthocyanins into the peel of cultivated tomatoes. For example, the dominant gene Anthocyanin fruit (*Aft)*, which induces limited pigmentation upon stimulation by high light intensity, was introgressed into domesticated tomato plants by an interspecific cross with *S. chilense* and the gene Aubergine (*Abg*) from *Solanum lycopersicoides,* Furthermore, the recessive gene atroviolacea (*atv*), derived from the interspecific cross with *Solanum cheesmaniae* that stimulate strong anthocyanin pigmentation in the entire plant, particularly in vegetative tissues. Fruits with either *Aft* and *atv* alleles or *abg* and *atv* alleles have been obtained with higher production of anthocyanins in the peel, ranging in total amount from 1 to 4 mg/g fresh weight of peel. Anthocyanins were found in the skin and flesh of certain cultivars of potato. Total anthocyanin concentrations in Andean potatoes ranged from 14 to 16, 330 μg/g DW [4]. Usually, cultivars high in anthocyanins are low in carotenoids and *vice versa*. The fruit color of red chili is genetically determined by three loci *y*, *cl*, and c*2* Recently the gene for capsanthin-capsorubin synthase (CCs) has been considered as candidate gene for the *y* locus. The relationship between the phytoene synthase and carotenoid content in chili was tested with interval mapping

using QTL analysis revealed that they were detected only at the *PSY* locus.

carrot germplasm, it is concluded that the *P*1 and *Y*2 loci are unlinked. The common cucumbers always develop white fruit with lower carotenoid, 22 48 μg/100 g fresh weight. While Xishuangbanna gourd (*C sativus var*.*xishuangbannanesis*) develops orange fruit rich in carotenoid, approximately 700 μg/100 g flesh weight, which makes this germplasm attractive to plant improvement programme. QTL associated with orange color fruit flesh showed two genetic

Singh *et al*. [13] observed enormous diversity in pigmentation of European and Asiatic carrot.The Asiatic types are mostly yellow and purple. The Asiatic type collection Local Rewari Black and Local Jaipur Black have higher anthocyanin content. Few molecular markers linked to major genes or QTL have been developed for carotene [14] and the *Y*2 gene and the *Rs* sugar type gene. To date, seven monogenic traits have been mapped for carrot: *yel, cola, Rs, Mj-1, Y,Y*2 and P1.QTL have been mapped for carrot total carotenoids and five component carotenoids: phytoene, x-carotene, ß-carotene, zeta-carotene, and lycopene [14] and the majority of the structural genes of the carotenoid pathway are now placed into this map. Anthocyanin accumulation in the carrot phloem is conditioned by the P1 locus, with purple (P1) dominant to non purple (p1). From the inheritance studies of Eastern
