Identification and Promotion of Heat Stress Resilient Maize Hybrids for Terai Region of Nepal. Keshab Babu Koirala

1. Keshab Babu Koirala
Coordinator
National Maize Research Program, Nepal
Identification and Promotion of Heat Stress Resilient
Maize Hybrids for Terai Region of Nepal

2. Contribution of Maize
Maize contributes about 3.15% in national
gross domestic products (GDP) and 9.5% in
AGDP
Occupies 26.97% area of the total food crops
(rice, maize, wheat, millet, barley and
buckwheat).

3.  Contribution of maize to total edible production
(5355232 tons) is 26.82% and to the total requirement
(5426631 ton) is 26.47% (MoAD, 2017)
 Mountain and hilly regions are food deficit and only
Terai has surplus edible production
 Total edible balance is 71399 tons in negative direction
in the country
Contribution of Maize contd...

4. Heat Stress
•Spring and early summer maize are mainly affected
by heat stress resulting yield losses up to 75 percent in
Nepal because of leaf firing, silk damage and tassel
blast
•Heat and drought stress during pollination and
fertilization can cause more yield loss than almost any
other period in the maize crop's development
•When temperature rises above 380C, silks do not
emerge at all and pollen grains burst causing very poor
pollination or no pollination at all producing barren
ears. It happens because of poor pollen viability and
poor pollen shed

5. Heat Stress
• Temperature increment was 0.040C in Terai and
0.080C in the Himalayas (Patricia, 2012) of Nepal
• It is estimated that average temperature in Nepal
increased at an annual rate of 0.060C from 1977 to 2000
•Therefore, a five-year HTMA project was initiated in
2013 with aim to identify and deploy heat stress
resilient maize hybrids in Nepal

6. Area & Productivity of Cereals in Nepal, MoAD, 2017
Crop
Area
(ha)
Area
(%)
Productivity
(kg/ha)
Paddy 1362908 41.22 3154
Maize 891583 26.97 2503
Wheat 745823 22.56 2329
Millet 266799 8.07 1133
Barley 28361 0.86 1157
Buckwheat 10842 0.33 1074

7. District Wise Edible Production in Nepal, 2015/016
(Out of 77 districts 36 districts have insufficient
edible balance)

8. Edible Requirement & Production, MoAD 2017
3000
3500
4000
4500
5000
5500
6000
6500 Total Production ('000 Mt) Total Requirement ('000 Mt)

9. Maize Production Environments in Nepal
Mountain
8.76%
Midhills
72.29%
Terai,
19.95%

10. 55
20
15
5 5
Maize Utilization pattern in Nepal (%)
Human
consumption
Poultry
Livestock
Industrial
Others

11. Makai Ek Prayog Anek

12. Trend of Maize Area, Production & Productivity in
Nepal (1990/091-2015/016)
0
500
1000
1500
2000
2500
3000
Area ('000 ha.) Production ('000 ton) Yield (kg/ha)

13. Maize Area (ha), Production (ton) & Productivity
(kg/ha) by Seed Type, MoAD, 2015/016
Ecological Belt Seed Type
Improved % Area Local % Area Total
MOUNTAIN
Area 71857 92 6248 8 78105 (8.76%)
Production 151617 10418 162035 (7.26%)
Yield 2110 1667 2075
Yld. Incr.t over Locl (%) 26.57
HILLS
Area 605812 94 38669 6 644481 (72.29%)
Production 1520588 65497 1586085 (71.08%)
Yield 2510 1694 2461
Yld. Incr.t over Locl (%) 48.18
TERAI
Area 163927 97 5070 3 168997 (18.95%)
Production 471618 11779 483397 (21.66%)
Yield 2791 2323 2725
Yld. Incr.t over Locl (%) 20.15
NEPAL
Area 841596 92 49987 8 891583
Production 2143824 87693 2231517
Yield 2547 1754 2503
Yld. Incr.t over Locl (%) 45.21

14. Seed replacement rate of maize is quite low (13%)
Area Covered by Maize Type (%) & Yield Gap ton/ha)
90%
5%5%
Improved OPVs
Hybrids
Landraces
6.7 t/ha
2.5 t/ha
5.7 t/ha
0
1
2
3
4
5
6
7
8
1
4.2
3.2
Maize Yield Gap (ton/ha) in Nepal

15. •Seven NMRP developed single cross hybrids
have been released/registered so far
Heat resilient Maize Hybrids Identified and
Rregistered by National System in 2017
Hybrid Source Yield, ton/ha Recommended Domain
Rampur Hybrid-10 CIMMYT,
Hyderabad
8.79 Terai and Inner Terai up to
700 Metre during WinterRampur Hybrid-8 9.18

16. Development of
Resilient Maize Varieties
Drought
for Hills
GLS for
Hills
Cold
Stress for
Terai
Heat
Stress
for Terai
Addressing Climate Change Issues
Low N

17. Leaf Firing
Results
Leaf Firing & Tassel Blast
Heat Stress Resilient Hybrids

18. Heat Stress Resilient Hybrids contd...
57 experiments consisting of 7764 genotypes
received from CIMMYT Hyderabad were
experimented at NMRP, Rampur; Regional
Agricultural Research Station (RARS),
Nepalgunj and Agricultural Research Station
(ARS), Surkhet during spring of 2013 - 2015

19. NMRP Rampur RARS Nepalgunj
ARS Surkhet
HTMA Sites in Nepal
ARS Surkhet

20. Heat Stress Resilient Hybrids contd...
At RARS Nepalgunj and ARS Surkhet
planting was managed in such a way that
anthesis and silking coincided with
temperatures above 380C
Total 24 hybrids were identified promising
 The selected 24 hybrids along with four
NMRP developed hybrids and two
multinational company hybrids (Pioneer
and Monsanto) were demonstrated

21. Dumarwana, Bara

22. Nijgadh, Bara

23. Keurini, Nawalparashi

24. NMRP Rampur

25. Selection of Hybrids
by Farmers,
Researchers,
Extension workers
and Seed
entrepreneurs

26. Table 1. Combined grain yield and other traits of HTMA hybrids
demonstrated over the locations (Dumarwana, Nijgadh, Keureni and Rampur)
2014/15 winter
Genotype
Grain yield
(t/ha)
Plant height
(cm)
Ear height
(cm)
E. turcicum
(1-5)
RML-95/RML-96 9.7 168 84 1.8
CAH151 9.2 168 71 1.5
RML-86/RML-96 8.9 170 84 1.9
CAH153 8.9 171 74 1.5
900M Gold 8.4 183 88 1.6
30V92 8.3 169 75 1.3

27. Table 2. Combined grain yield and other traits HTMA hybrids
demonstrated over the locations (Dumarwana, Nijgadh, Keureni
and Rampur) 2015/16 winter
Genotype Grain
yield
(t/ha)
Plant
height
(cm)
Ear
height
(cm)
E.
turcicum
(1-5)
CAH153 8.53 179 71 1.9
CAH1511 8.33 178 73 2.3
CAH1515 7.7 164 69 1.6
CAH151 7.23 186 85 1.6
RML-95/RML-96 6.45 171 93 2.1
RML-86/RML-96 6.38 161 92 1.9

28. Table 3. Combined grain yield and other traits of HTMA hybrids demonstrated
over the locations (Dumarwana, Nijgadh, Keureni and Rampur) and years
Genotype Grain yield
(t/ha)
Plant height
(cm)
Ear
height
(cm)
E. turcicum
(1-5)
CAH153 8.73 175 72 1.7
CAH1511 8.44 176 67 1.9
900M Gold* 8.4 183 88 1.6
30V92* 8.3 169 75 1.3
CAH151 8.19 177 78 1.6
RML-95/RML-96 8.06 169 88 1.9
RML-86/RML-96 7.66 165 88 1.9

29. Two hybrids, CAH151 and CAH153
performed better and preferred by
stakeholders across the experimental
and demonstration sites, and are
registered as Rampur Hybrid-8 and
Rampur Hybrid-10 for commercial
cultivation.
Heat Stress Resilient Hybrids contd...

30. Rampur Hybrid-8
Rampur Hybrid-10

31. Rampur Hybrid-8
Kernel is yellow/orange & flint type,
stay green, erect leaves, semi open
tassel, long ears and regular row
arrangement in the ear.
ZL126632: Seed/Female parent
CML-451: Pollen/Male parent

32. Rampur Hybrid-10
Orange-yellow kernel, flint, stay
green, erect leaves, semi open
tassel, light green stem color &
regular row arrangement in the
ear.
VL109126: Seed/Female
parent
CML-451: Pollen/Male parent