Marker-Assisted Introgression of opaque2 and crtRB1 for Enhancement of Amino Acids and Provitamin-A in Sweet Corn.Marker-Assisted Introgression of opaque2 and crtRB1 for Enhancement of Amino Acids and Provitamin-A in Sweet Corn

1. DIVISION OF GENETICS
ICAR-INDIAN AGRICULTURAL RESEARCH INSTITUTE
NEW DELHI, INDIA
Marker-Assisted Introgression of opaque2 and
crtRB1 for Enhancement of Amino Acids and
Provitamin-A in Sweet Corn
Speaker
Brijesh K. Mehta
Brijesh K. Mehta, Vignesh Muthusamy, Rashmi Chhabra, Aanchal Baveja,
Hema S. Chauhan, Rajkumar U. Zunjare and Firoz Hossain

2. ICAR-IndianAgriculturalResearchInstitute,NewDelhiICAR-IndianAgriculturalResearchInstitute,NewDelhi
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Production
Area
Productivity
Area(mha)&production(mt)
Productivity(Kg/ha)
Maize WORLD ASIA INDIA
Area (mha) 188 63.45 10.20
Production
(mt)
1060 324.08 26.26
References (faostat,
2017)
(faostat,
2017)
(www.indiastat.co
m)
Maize
Wider
adapta
bility
Food
Feed
Raw
material
Value
addition
Fuel
60%20%
14%
6%
Maize utilization pattern in India
Feed Food Starch Export & others

3. ICAR-IndianAgriculturalResearchInstitute,NewDelhi
 A type of corn with thin pericarp, high
sugar content and consumed at
immature stage of kernel development
at 20-24 DAP
 Among the several mutants that alters
starch composition, su1 and sh2
utilized the most in varietal
development
 Used as both fresh and processed
vegetables apart from component of
various snacks items
 After harvest of green cobs, green
plants serves as cattle fodder (extra
income to farmers)
Sweet corn Frozen Preserved Value (F+P)
(millions US $)
Global import 0.32 MT 0.72 MT 1457
Indian import 177 T 172 T 0.93
Source: FAOSTAT, 2017

4. ICAR-IndianAgriculturalResearchInstitute,NewDelhi
 Afflict more than two billion individuals worldwide, of which about 38% are
pregnant women and 43% are pre-school children (Garg et al., 2018)
 VAD Affects nearly 190 million preschool-
age children and nearly 20 million
pregnant women of which about one-
third are clinically night-blind (WHO,
2009)
 In India, about 40 million pre-school
children (Akhtar et al., 2013), and nearly
10 million pregnant women are vitamin-A
deficient (www.harvestplus.org)
VAD
Color
blindness
Growth
retardation
Xeropthalmia
Disease
susceptibility
Lys & Trp
deficiency
Fatigue
Growth
retardation
Loss of
appetite
Depression
and anxiety
 Protein energy malnutrition (PEM) affects
more than a billion people across the
world (Hossain et al., 2018; Sarika et al.,
2018)

5. ICAR-IndianAgriculturalResearchInstitute,NewDelhi
 Biofortification is the
process of breeding staple
food crops that are high
yielding and dense in
minerals and vitamins
Biofortification
 Provides a sustainable
solution to the problem
 Cost effective

6. ICAR-IndianAgriculturalResearchInstitute,NewDelhi
S. No. Recipient Donor
1. SWT016 HKI193-2
2. SWT017 HKI161
3. SWT018 HKI161
S. No. Hybrids Parents
1. ASKH-1 SWT016 x SWT017
2. ASKH-2 SWT016 x SWT018
Table: Recipient and donor inbreds used in the programme
Dehusked cob
yield:
ASKH-1: 10.8 t/ha
ASKH-2: 9.8 t/ha
Sweetness in
Kernel:
20-22% brix
ASKH-1
Sweet corn
Composites:
Priya, Madhuri,
punjab sweet corn-1
& Win Orange
Sweet corn hybrids:
HSC-1
ASKH-4
VL Sweet Corn-1
ASKH-2

7. ICAR-IndianAgriculturalResearchInstitute,NewDelhi
 The backcross- and selfed- progenies were advanced at two places: Experimental
Farm, ICAR-IARI, New Delhi and WNC, ICAR-IIMR, Hyderabad
K- 2015
R- 2016-17
K- 2016
K- 2017
R- 2017-18
R- 2015-16
x x
F1 F1

8. ICAR-IndianAgriculturalResearchInstitute,NewDelhi

9. ICAR-IndianAgriculturalResearchInstitute,NewDelhi
LG No. of markers screened RNP Pol. (%)
1. 22 8-11 36.36-50.00
2. 19 7-10 36.84-52.63
3. 33 14-22 42.42-66.66
4. 23 7-14 30.43-60.86
5. 24 8-13 33.33-54.16
6. 20 9-12 45.00-60.00
7. 20 9-16 45.00-80.00
8. 18 7-9 38.88-50.00
9. 18 6-9 33.33-50.00
10. 24 7-14 29.16-58.33
Total 221 102-113 46.15-51.13
Table- Chromosome wise SSRs screened and percentage polymorphism observed across crosses
LG: Linkage group; RNP: Range of no. of observed polymorphic markers across crosses; Pol. (%): Range of polymorphism percentage across crosses

10. ICAR-IndianAgriculturalResearchInstitute,NewDelhi
S. No. Generation N C+C+ C+C CC χ2 P-value o2o2 O2o2 O2O2 χ2 P-value
1. BC1F1 256 - 83 173 31.64 <0.0001** - 124 132 0.25 0.6170ns
2. BC2F1 318 - 145 173 2.46 0.1167ns - 160 158 0.01 0.9203ns
3. BC2F2 642 117 307 218 33 <0.0001** 114 330 198 22.48 <0.0001**
Table- Segregation pattern of crtRB1, and opaque2 in different backcross- and self- generations across three crosses
**Significant at P = 0.01; ns: Non significant; N: No. of plants genotyped; df: degrees of freedom; C+: favourable allele of
crtRB1; C: unfavourable allele of crtRB1; o2: favourable allele of opaque2; O2: unfavourable allele of opaque2
Fig.- Segregation of o2 and crtRB1 in BC2F2 generation (SWT-016-based). Star indicates segregants with donor
allele in homozygous conditions

11. ICAR-IndianAgriculturalResearchInstitute,NewDelhi
S. No. Generation Range of RPG (%) across crosses Average RPG (%) across crosses
1. BC1F1 70.48 ̶ 82.30 77.49
2. BC2F1 83.19 ̶ 92.86 87.20
3. BC2F2 88.24 ̶ 96.19 92.31
Table- Recurrent parent genome recovery (RPG) (%) of introgressed lines across crossess
umc1076 umc1446
D R BC2F2
D R BC2F2

12. ICAR-IndianAgriculturalResearchInstitute,NewDelhi
S. No. Component Normal Improved
1. ProA ~3-4 ppm ~17.5-23.5 ppm
2. Lysine ~2-2.5 % ~4-5 %
3. Tryptophan ~0.4-0.6 % ~0.8-1.2%

13. ICAR-IndianAgriculturalResearchInstitute,NewDelhi
 BC1F1, BC2F1 and BC2F2 populations were successfully genotyped using markers
associated with o2 and crtRB1
 Heterozygotes in backcross generations and homozygotes in selfed generations
were identified
 Background selection led to the high recovery of RPG
 The selected progenies with sh2, o2 and crtRB1 possessed similar plant, ear and
grain characteristics of recurrent parent

14. ICAR-IndianAgriculturalResearchInstitute,NewDelhi
• Dean and Director, IARI, New
Delhi
• ICAR - for funding
• CSIR – Junior Research Fellowship
• Director, IIMR, Ludhiana
• Maize Genetics Unit, IARI
Maize Genetics Unit, IARI