**5. Genetics**

Information on the genetics of unusual traits in a crop is crucial for its systematic breeding programmes. Several studies have been conducted to know the genetics of qualitative and quantitative traits in addition resistance to major diseases and insect pests in mungbean, the results of which are presented in **Table 1**.



**53**

*Mungbean (*Vigna radiata *L. Wilczek): Retrospect and Prospects*

Simple inflorescence is governed by two dominant genes ('I1', '12') and double recessive homozygous genotype results in the compound

Inheritance of the number of clusters per node shows that a single dominant gene 'C' conditions one cluster per node and its recessive counterpart 'c' determines three clusters per node

A flower mutant with extended stigma and male sterility

namely, red yellow, olive yellow, yellowish olive and light yellowish

Light yellowish olive colour is partially dominant to olive yellow

Pubescence Dense plant pubescence Single dominant gene

Brown colour of the trait is recessive to colourless and therefore, dominant forms of both the genes are required for colourless pubescence

Pod pubescence is dominant over

also conditions the colour of unripe

Purple colour on the suture of

Swollen tip is dominant over

Resistance to shattering in the interspecific hybrids between mungbean and urd bean was dominant but nonshattering plants could not be recovered in the segregating generations suggesting that the pod shattering is a quantitatively inherited trait

tapering pod tip

Inheritance of dry pod colour for light popcorn and almond biscuit

Colour of mature pods Single dominant gene

non-pubescence

Pod colour A gene responsible for flower colour

unripe pod

colours

Pod shattering Pod shattering is dominant to non-shattering

pods

**Characteristic Gene involved References**

Induced sterility Single dominant gene [48, 49]

('I1', '12')

Two dominant genes

Monogenic recessive inheritance

Single partially dominant gene with gene symbols of 'Pg', 'Pb'

'Dp'

Single dominant gene [47]

Single dominant gene [31]

Two genes 'N' and 'Br' [26]

Single dominant gene [52]

Single dominant gene [31]

Single dominant gene [28]

Genes 'lp' and 'lab' [26]

A single gene [53]

A single gene [54]

with black dominant over light brown colour

Single dominant gene

'Tp'

[32]

[50]

[51]

[51]

[28]

[26]

*DOI: http://dx.doi.org/10.5772/intechopen.85657*

inflorescence

Flower colour Four colours of the standard petal

olive

**Qualitative traits**

Inflorescence type


*Legume Crops – Characterization and Breeding for Improved Food Security*

'P' gene for the purple hypocotyl and a multiple allelic series 'C', 'C' and 'c' for purple, purple spotted

Anthocyanin pigmentation in hypocotyl, epicotyl, stem, petiole

A gene 'R' that conditions red colour of the cotyledons, hypocotyls and

Anthocyanin pigmentation in the hypocotyl, epicotyl, stem, petiole,

Purple pigmentation on stem, petiole and veins of leaves

large leaflet is dominant over small

Induced unifoliata and multifoliata

Lobed trifoliate leaf is dominant

Chlorophyll mutants have been reported in mungbean with lethal and nonlethal effects. The albino seedling is controlled by monogenic recessive inheritance for the induced xantha, variegata, and greenish yellow chlorina mutants

Independent monogenic recessive inheritance for albina, chlorina, xantha and virescens types of chlorophyll mutants

Anthocyanin in hypocotyl Two supplementary

Pigmentation Purple hypocotyl which is dominant over green hypocotyl

and green epicotyl

top of the leaflet stalk

and peduncle

and peduncle

Stem fasciation Stem fasciations on the number of floral organs

Leaf traits Inheritance of leaf size revealed that

leaf mutants

over entire leaf

leaflet

**Characteristic Gene involved References**

Single gene 'A' [31]

Single dominant gene [32]

Single dominant genes [33]

Single recessive gene [35]

[36]

[37]

[38]

[40]

[37]

[44]

[42]

genes, designated as 'Sh' and 'Ph' with recessive epistatic interaction

Single dominant gene 'Pppl' with pleiotropic

Single recessive gene 'fsl' with a pleiotropic effect

duplicate gene action

'Tibl' and 'T1b2' with duplicate action

Single recessive 'al' and

and 'n12'

'I' genes

Single dominant gene [37]

Single recessive genes [42]

Single dominant gene [39, 43]

Single recessive gene [45, 46]

effect

Pentafoliate leaf One recessive gene [39]

Nine foliate leaf mutant Single recessive gene [41]

Pentafoliate leaf Two recessive genes with

Narrow lanceolate leaf Two recessive genes, 'nil'

Trilobite leaf Two dominant genes

Single dominant genes [28, 33, 34]

**Qualitative traits**

**52**

Chlorophyll mutants


**55**

**7. Research needs**

*Mungbean (*Vigna radiata *L. Wilczek): Retrospect and Prospects*

Green cotyledon is conditioned by which is inherited independently of the red colour present in the hypocotyl and petiole

The photoperiod insensitiveness is reportedly dominant over photo-sensitiveness

Traditionally, mungbean has been grown during kharif season. Development of short duration and disease resistant varieties has led their cultivation during spring/summer season in North and central India and during winter (rice fallows) in the coastal peninsula. The major constraints in achieving higher yield are lack of exploitable genetic variability, absence of suitable ideotypes for different cropping systems, poor harvest index, and susceptibility to biotic and abiotic stresses, besides non-availability of quality seeds of improved varieties. The major yield limiting harriers are lack of seedling vigour, excessive flower production, flower drops, poor pod setting, poor harvest index, monocarpic senescence, low response to inputs, narrow adaptation, indeterminate growth habit, staggered maturity and sensitivity to photoperiods and temperature. The phenomenon of compensation among yield components is considered to be main yield limiting factor. Limited variability has been exploited in varietal development programmes of these crops. Pedigree analysis of the released cultivars indicated that a small number of parents with high degree of relatedness were repeatedly used in crossing programmes. Diseases and insect pests cause considerable yield losses to mungbean. Mungbean yellow mosaic virus (MYMV), cercospora leaf spot (*C. canescens*, *C. cruenta*) and powdery mildew (*Ertisiphe polygoni* DC) are of considerable economic importance. Mungbean yellow mosaic virus and leaf crinkle during kharif and mungbean yellow mosaic virus during spring in North India and powdery mildew during winter season in coastal peninsula are the major diseases. During the vegetative stage, defoliators like hairy caterpillars, semi-looper and caterpillar are the common pests. Activity of thrips starts at the bud stage and poses serious problems when the crop attains peak flowering, resulting in heavy flower drop. There is no resistant variety against these insect pests. Pre-harvest sprouting especially in mungbean poses a serious threat to timely sown crop during rainy season. Intense heat and hot winds during May-June

Hard seededness Single dominant gene,

**Characteristic Gene involved References**

'Hdl'

Hard seededness Four QTL [63]

Single recessive gene 'gc' [61]

A single gene [64]

[62]

lead to flower drop and poor pod set in spring/summer crop.

Varieties developed in the past with resistance to single stress may not be a viable

solution as new diseases and insect pests are emerging. Therefore, varieties having resistance to more than one stress provide greater insurance. For mungbean, high yielding cultivars with crop duration of 85–90 days for kharif season and

*DOI: http://dx.doi.org/10.5772/intechopen.85657*

**Qualitative traits**

Cotyledon colour

Hard seededness

**Table 1.**

Photoperiod response

**6. Production constraints**

*Genetics of qualitative traits.*


#### **Table 1.**

*Legume Crops – Characterization and Breeding for Improved Food Security*

seeds is under the quantitative genetic control while inheritance of the brown pigment in the texture layer The presence of brown pigment being dominant to its absence

Inheritance of mottling in the seed coat is monogenic. The presence of anthocyanin being dominant to its absence. It indicated that the inheritance of black and green seed colours was controlled by a single gene, 'B' with black being dominant

Seed coat colour Thickness of the texture layer in

over green

Seed coat colour

non-spotted colours

Seed coat colour

seed coat

are 'C'

Black, brown, green mosaic, yellow mosaic, amber, green, and yellow

Dull rough seed surface is monogenically dominant over glossy smooth surface and the gene symbols assigned for dull seed coat

Digenic duplicate interaction (D1 and D2) is involved in the inheritance of seed luster, dullness being dominant over shiny

The dominant alleles, 'A' and 'Sp', condition green and spotted seed coat whereas their recessive counterparts confer yellow and

Each gene conditioning blue sap colour, buff sap colour and green chloroplast, respectively which together define the seed coat colour

**Characteristic Gene involved References**

Seed coat colour A single gene [57]

dominant genes

'Dgsm2'

and 'G'

Seed coat colour Three-gene model [58]

Three gene pairs, 'Br', br

several modifiers giving mottling patterns on yellow (mmbbgg), yellow green (mmBBgg), green (mmBBGG) and black (MMBBGG) seed coats

Four-gene (W, M, 'Br

with non-allelic gene interactions

and G)

Seed coat colour Two independent

Seed colour Two genes, 'Dgsml' and

Seed coat colour Three genes with

Inheritance of seed coat colour Five major genes

genes

Two complementary

A single gene [56]

Two gene pairs [33]

[55]

[31]

[37]

[26]

[59]

[60]

[39]

Single dominant gene [26, 31, 33, 61]

Two dominant gene [41]

**Qualitative traits**

**54**

Seed coat surface

*Genetics of qualitative traits.*
