**7.2 Cucurbitaceous vegetables**

To exploit heterosis in cucurbits the essential requirement is heterotic combination potential of crops from flower size to pollination and fruit set resulted in proper seed setting to economic feasibility. The cucurbit vegetables have a more substantial size of male and female flowers and allow following other systems of pollination

**63**

into cabbage [48].

**7.4 Carrot (***Daucus carota* **L.)**

frequent deterioration to male fertility [49].

**7.5 Bulb crops—onion (***Allium cepa* **L.)**

environments [50, 51].

**8. Self-incompatibility**

*Directing for Higher Seed Production in Vegetables DOI: http://dx.doi.org/10.5772/intechopen.90646*

control strategies. The hand emasculation with hand and natural pollination mechanism used in hybrid seed production in bottle gourd, pumpkin, squash, cucumber, muskmelon and bitter gourd with specific planting ratio. Genetic male sterility mainly uses in muskmelon, and most of the genetic male-sterile mutants in cucurbits are monogenic recessive. There are many types of male sterility identified in cucurbits, but commercial exploitation is still lacking. Gynoceious lines based on genetic male sterility (GMS) stability gene and use of different plant growth regulators are also useful in hybrid seed production of cucurbits with sex modification [46].

Cole crops and some root crops are a significant group of vegetables in the brassica family, and they are cabbage, cauliflower, broccoli, turnip and radish. GMS, CGMS and self-incompatibility (SI) are important pollination mechanism available in Brassica family to get a higher percent of heterosis in crops. In which, self-incompatibility (Sporophytic self-incompatibility) system is most useful in hybridisation program. But, CGMS method also developed with some selfpollination occurrence [47]. In cole vegetables, sterile cytoplasm (CMS system) derived from *B. nigra* through interspecific hybridisation between *B. nigra* and *B. oleracea* var. italica and Ogura type CMS also identified and reported in cultivar Japanese radish of *Raphanus sativus*. First, introgression of this sterility cytoplasm to *Brassica oleraceae* genome through repeated backcrosses with broccoli. Some plant physiological problems were found in Ogura based CMS lines of broccoli, cauliflower, cabbage, Brussels sprout and it has been solved using protoplast fusion, and this technique is also used in transfer Ogura cytoplasm from broccoli

Cytoplasmic male sterility in carrot can occur in two morphologically (brown anther and petaloid) distinct phenotypes. The brown anther male sterility was first discovered in the cultivar Tendersweet, and this is, characterised by shrivelled, yellow-to-brown anthers with no pollen. It is a homeotic mutation. This is established as the white petaloidy or green petaloidy. It is stable male sterility across a wide range of environments as compared to brown anther type. Seed yield of the brown-anther CMS are generally higher because of petaloid sterility shows less

Male sterility in onion, first reported in the progenies of an onion cultivar Italian Red plants and is controlled by the combination of a cytoplasmic factor "S" together with a recessive nuclear restorer locus in its homozygous form (ms) and "T"-cytoplasm has been reported. Onion (*Allium cepa* L.) hybrid seed production has been produce in all over the world through CGMS-based systems in which mostly hybrids are derived from S-cytoplasm because of its stability in various

Self-incompatibility can be a widespread phenomenon in vegetable crops that forestalls inbreeding and encourages outcrossing. The response of self-incompatibility

**7.3 Cole crops (***Brassica oleracea* **L.) and radish (***Raphanus sativus***)**

*Directing for Higher Seed Production in Vegetables DOI: http://dx.doi.org/10.5772/intechopen.90646*

*Agronomy - Climate Change and Food Security*

**7. Role of male sterility in vegetables**

*7.1.1 Pepper/Chilli* (Capsicum annuum L.)

Peterson (1958) first reported the cytoplasmic genetic male sterility (CGMS) in chilli in an introduction of *C. annuum* from India (PI-164835) and found its instability under fluctuating conditions, particularly temperatures and natural cross-pollination. Genetic male sterility in chilli well exploited on a commercial scale in hybrid seed production. Male sterile plants easy to identify in the field at a comparatively early stage. Nearly 20 genes governed genetic male sterility. The ms-10 gene is linked with taller plant height, erect growth and dark purple anther. MS-12 (ms-509/ms-10) and ms-3 genes are commercially utilised in India and

*7.1.2 Tomato* (Solanum lycopersicum L.) *and brinjal* (Solanum melongena L.)

optimise crossing resulted in reducing the cost of hybrid seed production [45].

Tomato crop has different types of male sterility identified, but presently commercial hybrid seed production in tomato and brinjal possible with manual emasculation and hand pollination and it is economically viable and dominates in the seed industry. Though, the availability of different sterility methods can be used to avoid selfing and

To exploit heterosis in cucurbits the essential requirement is heterotic combination potential of crops from flower size to pollination and fruit set resulted in proper seed setting to economic feasibility. The cucurbit vegetables have a more substantial size of male and female flowers and allow following other systems of pollination

**7.1 Family: solanaceae**

*Different stages of seed development.*

**Figure 1.**

Hungry, respectively [44].

**7.2 Cucurbitaceous vegetables**

**62**

control strategies. The hand emasculation with hand and natural pollination mechanism used in hybrid seed production in bottle gourd, pumpkin, squash, cucumber, muskmelon and bitter gourd with specific planting ratio. Genetic male sterility mainly uses in muskmelon, and most of the genetic male-sterile mutants in cucurbits are monogenic recessive. There are many types of male sterility identified in cucurbits, but commercial exploitation is still lacking. Gynoceious lines based on genetic male sterility (GMS) stability gene and use of different plant growth regulators are also useful in hybrid seed production of cucurbits with sex modification [46].

## **7.3 Cole crops (***Brassica oleracea* **L.) and radish (***Raphanus sativus***)**

Cole crops and some root crops are a significant group of vegetables in the brassica family, and they are cabbage, cauliflower, broccoli, turnip and radish. GMS, CGMS and self-incompatibility (SI) are important pollination mechanism available in Brassica family to get a higher percent of heterosis in crops. In which, self-incompatibility (Sporophytic self-incompatibility) system is most useful in hybridisation program. But, CGMS method also developed with some selfpollination occurrence [47]. In cole vegetables, sterile cytoplasm (CMS system) derived from *B. nigra* through interspecific hybridisation between *B. nigra* and *B. oleracea* var. italica and Ogura type CMS also identified and reported in cultivar Japanese radish of *Raphanus sativus*. First, introgression of this sterility cytoplasm to *Brassica oleraceae* genome through repeated backcrosses with broccoli. Some plant physiological problems were found in Ogura based CMS lines of broccoli, cauliflower, cabbage, Brussels sprout and it has been solved using protoplast fusion, and this technique is also used in transfer Ogura cytoplasm from broccoli into cabbage [48].

### **7.4 Carrot (***Daucus carota* **L.)**

Cytoplasmic male sterility in carrot can occur in two morphologically (brown anther and petaloid) distinct phenotypes. The brown anther male sterility was first discovered in the cultivar Tendersweet, and this is, characterised by shrivelled, yellow-to-brown anthers with no pollen. It is a homeotic mutation. This is established as the white petaloidy or green petaloidy. It is stable male sterility across a wide range of environments as compared to brown anther type. Seed yield of the brown-anther CMS are generally higher because of petaloid sterility shows less frequent deterioration to male fertility [49].

#### **7.5 Bulb crops—onion (***Allium cepa* **L.)**

Male sterility in onion, first reported in the progenies of an onion cultivar Italian Red plants and is controlled by the combination of a cytoplasmic factor "S" together with a recessive nuclear restorer locus in its homozygous form (ms) and "T"-cytoplasm has been reported. Onion (*Allium cepa* L.) hybrid seed production has been produce in all over the world through CGMS-based systems in which mostly hybrids are derived from S-cytoplasm because of its stability in various environments [50, 51].

## **8. Self-incompatibility**

Self-incompatibility can be a widespread phenomenon in vegetable crops that forestalls inbreeding and encourages outcrossing. The response of self-incompatibility is genetically managed by several multi-allelic loci and depends on many intricate interactions among the self-incompatible pollen and pistil combinations. It is genetically regulated phenomena that function as a barrier to self-pollination in the big selection of vegetable crops like cabbage, cauliflower, tomato and many others. Self-incompatibility can be a critical system by which crops avert self-fertilisation and keep a broad genetic range. Self-incompatibility is considered to present in 30–50% of flowering plant species [52]. Many SI programs have now been discovered. In all situations, incompatible (self-) pollen is considered by a distinct system usually genetically managed that brings about inhibition on the pollen while in the stigma or on the pistil. Using SI in F1 hybrid generation has key gain over other approaches. Usage of Self-incompatibility in cole crops for hybrid seed generation is commercialised due to the availability of a robust mechanism/method to create large-scale F1 seeds employing picked parental strains is undoubtedly a critical issue, which in the long run establishes the professional viability on the hybrid varieties [53].

Self-incompatibility is classified as namely gametophytic and sporophytic. In gametophytic technique self-incompatibility response of pollen and stigma is decided with the genotype of the female plant on which pollens are developed (e.g. tomato) even though in sporophytic technique, pollen phenotype (selfincompatibility response) is identified with the genotype on the female plant on which pollens are developed (e.g. cole greens). In Brassicaceae, sporophytic selfincompatibility (SSI) has been ideally characterised and productively used for that growth of commercial hybrids. Using SI in F1 hybrid generation has key gain over other approaches; equivalent portions of seed on the two inbred strains can be blended jointly for demonstrating, along with the total crop is harvested for seed. For hybrid seed generation, equally the parental inbreds need to have two diverse S alleles for sturdy self-incompatibility in the event of one cross hybrid. Among the cole greens like cabbage, cauliflower, broccoli and many others, sporophytic self-incompatibility system is currently being used for the hybrid seed generation at many spots in India [54]. Usually in cauliflower self-incompatibility is weak, and its response is broken at substantial temperature. Self-incompatibility can be a technique employed by a lot of flowering plant species to forestall self-fertilisation and thus encourage outcrossing. Above the several years, considerable perception in the mechanisms regulating self-incompatibility has become attained for that Solanaceae gametophytic self-incompatibility programs at the same time as for that sporophytic self-incompatibility technique of the Brassicaceae in vegetable crops. A mix of genetic and molecular reports have resulted while in the identification and characterisation of the self-incompatibility genes associated with this particular reaction.

Moreover, careful investigation on the factors in the signalling cascades of equally the Solanaceae along with the Brassicaceae is necessary for an entire idea of the self-incompatibility reaction in these people. Several mechanisms and approaches have not been exploited for that growth of professional hybrids in vegetable crops between that SI is of crucial relevance. While in the light-weight of the quick progression of biotechnology, it could be expected that SI programs are going to be ever more used near foreseeable future, in vegetable crops [55].

### **9. Growth regulators**

Growth regulators are organic chemical substances which, when applies in small quantities aid in the regulation of plant growth and modify the physiological response in plants. Growth regulators have immense importance in enhancing

**65**

*Directing for Higher Seed Production in Vegetables DOI: http://dx.doi.org/10.5772/intechopen.90646*

control fruits drops, regulation of flowering.

(PGRs) are listed below:

and fruit size.

senescence of leaf.

reviewed in **Table 3**:

prolongation of vegetables.

development and germination.

6.Flowering hormones (florigen, vernalin).

7.Natural substances (vitamins, phytochrome tranmatic).

**PGR Target/response Crop**

GA3 Abnormalities in pollen development

stamens

Ethrel Decreased number of staminate flowers

GA3 Leaf morphogenesis, promote normal

8.Synthetic substances (synthetic auxins, synthetic cytokinins).

and induced the carpelization of

stamen and pollen development

GA3 Increased number of female flowers Bitter gourd

GA3 Lower male and female flower ratio Cucumber GA3 Induce parthenocarpy Bitter gourd

GA3 Production of male sterile flowers Onion, Brussels sprouts, cabbage,

Ethrel Increased number of pistillate flowers Cucumber, pumpkin, pointed gourd,

vegetable production and have been used to improve seed germination, increase in yield and tolerance against diseases and unfavourable conditions [56]. Apart from these functions growth regulators have usefulness in vegetable seed production by altering sex expression, increasing fruit set as well as seed yield and inducing male sterility, without exerting any harmful effects on the environment and human health [57]. Classification and functions of different plant growth regulators

1.Auxins (IAA, NAA, IBA, 2,4-D, 4-CPA): apical dominance, root induction,

2.Gibberellins (GA3): seed germination, stimulates flowering, increase flower

3.Cytokinins (kinetin, zeatin): bud initiation and root growth, storage life

4.Ethylene (etheral): uniform ripening in vegetables, promotes abscission,

5.Abscisic acid (dormins, phaseic acid): stress hormone, dormancy, seed

Role of different PGRs in vegetable production of different vegetable crops are

GA3 Fruit setting, seed yield and quality Bittergourd, muskmelon, tomato, chilli,

capsicum, brinjal, cauliflower, cabbage,

Cucumber, bittergourd, pumpkin, sponge

melons, snake gourd, sponge gourd, bottle gourd, bitter gourd, summer squash

okra, cucurbits, potato, pea

Pepper

Tomato

gourd

cauliflower and kale

## *Directing for Higher Seed Production in Vegetables DOI: http://dx.doi.org/10.5772/intechopen.90646*

*Agronomy - Climate Change and Food Security*

varieties [53].

particular reaction.

**9. Growth regulators**

is genetically managed by several multi-allelic loci and depends on many intricate interactions among the self-incompatible pollen and pistil combinations. It is genetically regulated phenomena that function as a barrier to self-pollination in the big selection of vegetable crops like cabbage, cauliflower, tomato and many others. Self-incompatibility can be a critical system by which crops avert self-fertilisation and keep a broad genetic range. Self-incompatibility is considered to present in 30–50% of flowering plant species [52]. Many SI programs have now been discovered. In all situations, incompatible (self-) pollen is considered by a distinct system usually genetically managed that brings about inhibition on the pollen while in the stigma or on the pistil. Using SI in F1 hybrid generation has key gain over other approaches. Usage of Self-incompatibility in cole crops for hybrid seed generation is commercialised due to the availability of a robust mechanism/method to create large-scale F1 seeds employing picked parental strains is undoubtedly a critical issue, which in the long run establishes the professional viability on the hybrid

Self-incompatibility is classified as namely gametophytic and sporophytic. In gametophytic technique self-incompatibility response of pollen and stigma is decided with the genotype of the female plant on which pollens are developed (e.g. tomato) even though in sporophytic technique, pollen phenotype (selfincompatibility response) is identified with the genotype on the female plant on which pollens are developed (e.g. cole greens). In Brassicaceae, sporophytic selfincompatibility (SSI) has been ideally characterised and productively used for that growth of commercial hybrids. Using SI in F1 hybrid generation has key gain over other approaches; equivalent portions of seed on the two inbred strains can be blended jointly for demonstrating, along with the total crop is harvested for seed. For hybrid seed generation, equally the parental inbreds need to have two diverse S alleles for sturdy self-incompatibility in the event of one cross hybrid. Among the cole greens like cabbage, cauliflower, broccoli and many others, sporophytic self-incompatibility system is currently being used for the hybrid seed generation at many spots in India [54]. Usually in cauliflower self-incompatibility is weak, and its response is broken at substantial temperature. Self-incompatibility can be a technique employed by a lot of flowering plant species to forestall self-fertilisation and thus encourage outcrossing. Above the several years, considerable perception in the mechanisms regulating self-incompatibility has become attained for that Solanaceae gametophytic self-incompatibility programs at the same time as for that sporophytic self-incompatibility technique of the Brassicaceae in vegetable crops. A mix of genetic and molecular reports have resulted while in the identification and characterisation of the self-incompatibility genes associated with this

Moreover, careful investigation on the factors in the signalling cascades of equally the Solanaceae along with the Brassicaceae is necessary for an entire idea of the self-incompatibility reaction in these people. Several mechanisms and approaches have not been exploited for that growth of professional hybrids in vegetable crops between that SI is of crucial relevance. While in the light-weight of the quick progression of biotechnology, it could be expected that SI programs are going to be ever more used near foreseeable future, in vegetable crops [55].

Growth regulators are organic chemical substances which, when applies in small quantities aid in the regulation of plant growth and modify the physiological response in plants. Growth regulators have immense importance in enhancing

**64**

vegetable production and have been used to improve seed germination, increase in yield and tolerance against diseases and unfavourable conditions [56]. Apart from these functions growth regulators have usefulness in vegetable seed production by altering sex expression, increasing fruit set as well as seed yield and inducing male sterility, without exerting any harmful effects on the environment and human health [57]. Classification and functions of different plant growth regulators (PGRs) are listed below:


Role of different PGRs in vegetable production of different vegetable crops are reviewed in **Table 3**:



#### **Table 3.**

*Growth regulators used for higher seed production in the vegetables based on Prajapati et al. [58].*

### **10. Conclusions**

The essence of any seed programme is the excellent quality of seed, and this trait varies from the standpoint of genetic purity. The seed programme with no proper quality management of the seed will tend to fail. For that reason, the quality of vegetable seed is a necessary consideration. Underneath a standard seed technology chain, breeder seed is multiplied from nucleolus seed. The exercise of bulk enhance

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*Directing for Higher Seed Production in Vegetables DOI: http://dx.doi.org/10.5772/intechopen.90646*

The authors declare no conflict of interest.

, Dinesh Kumar Saini2

Universitat Politècnica de València, Valencia, Spain

\*Address all correspondence to: prakau@doctor.upv.es

provided the original work is properly cited.

, Prashant Kaushik3

1 Department of Vegetable Science, Punjab Agricultural University, Ludhiana, India

2 Department of Plant Breeding, Punjab Agricultural University, Ludhiana, India

4 Department of Botany, Kurukshetra University, Kurukshetra, Haryana, India

5 Department of Agronomy, CCS Haryana Agricultural University, Hisar, India

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

3 Instituto de Conservación y Mejora de la Agrodiversidad Valenciana,

\*, Jyoti Chauhan4

production cannot be denied.

**Conflict of interest**

**Author details**

Navjot Singh Brar1

and Navish Kumar Kamboj<sup>5</sup>

of breeder seed and endless multiplication cycles of basis seed with no likely again to breeder seed may severely influence the standard of seed and may be discontinued. Importance of good quality seed can be determined from the fact that seed is the indispensable input for crop production. The top-quality seed is the carrier of the resistance gene or good genes selected by the breeder. Seed ensures food supply under adverse production sites; therefore, the importance of seeds for vegetable

*Directing for Higher Seed Production in Vegetables DOI: http://dx.doi.org/10.5772/intechopen.90646*

of breeder seed and endless multiplication cycles of basis seed with no likely again to breeder seed may severely influence the standard of seed and may be discontinued. Importance of good quality seed can be determined from the fact that seed is the indispensable input for crop production. The top-quality seed is the carrier of the resistance gene or good genes selected by the breeder. Seed ensures food supply under adverse production sites; therefore, the importance of seeds for vegetable production cannot be denied.
