This document provides an update on CIMMYT's maize products that are tolerant to maize lethal necrosis (MLN). It discusses MLN tolerant germplasm that has been distributed to various countries in East and Southern Africa. Some MLN tolerant hybrids have entered national performance trials in Kenya, Tanzania, and Uganda and have shown moderate tolerance to MLN. Five hybrids have been recommended for release or already released in Kenya, Uganda, and Tanzania. Challenges remain in developing parents that are all resistant to MLN and in finding MLN-free areas for seed production. Overall, progress is being made in developing and distributing MLN tolerant maize varieties and hybrids to countries affected by the disease

1. New CIMMYT-derived products with
MLN tolerance
Naivasha
March 2015

2. Outline
● CIMMYT MLN tolerant products
● MLN tolerant germplasm seed request, dispatch and source
● MLN tolerant NPT hybrids
● MLN tolerant hybrid releases
● Other related activities
● Challenges

3. CIMMYT MLN tolerant products
● UPDATE: Promising CIMMYT maize inbreds and pre-commercial hybrids-June 2013
● Update: CIMMYT maize inbred lines and pre- commercial hybrids with potential
resistance to maize lethal necrosis (MLN)-May 2014

4. MLN tolerant germplasm seed request, source and dispatch in ESA:
2013/14
Country No of
NARS/Cen
ters
Seed
companies
No of
inbred
lines
No of
hybrids
Source/
CIMMYT
South
Africa
- 1 2 - Zimbabwe
Ethiopia 1 - 2 - Zimbabwe
Kenya 3 4 4-18 4-17 Kenya
Uganda 1 2 4-18 4-17 Kenya
Tanzania 1 4 7-16 4-17 Kenya
Total 6 11
17 partners in 5 countries received germplasm

5. MLN tolerant germplasm seed request, source and dispatch in ESA:
2014/15
Country No of
NARS/
Centers
Seed
companies
No of
inbred
lines
No of
hybrids
Source/
CIMMYT
South Africa 1 4 Zimbabwe
Ethiopia 1 CMLs Gene bank
Zimbabwe 1 2 35 Zimbabwe
Zambia 1 5 Zimbabwe
Malawi 1 5 Zimbabwe
Mozambique 1 13 Zimbabwe
Kenya 5 6 11-30 1-3 Kenya
Uganda 2 1 30 2 Kenya
Tanzania 1 4 30 1-4 Kenya
Rwanda 1 - 20 6 Kenya
Total 13 15
28 partners in 10 countries received germplasm
Seed produced under supervision of KEPHIS

6. Some MLN tolerant hybrids were advanced to NPT in KE, TAN and UG
Also, some MLN tolerant hybrids were already in NPT in 2013
Country No of MLN tolerant hybrids in NPT
in 2014
Kenya 4
Tanzania 4
Uganda 3

7. Hybrid
NPT in
Country
MLN Severity Score (1-5 Scale) at
Naivasha (2014)
UH5558 Uganda 2.8
CHMLND0086 Tanzania 2.8
CKH12602 Kenya 3.0
CKH12603 Uganda 2.8
MERU HB607 Tanzania 3.0
CKH12613 Tanzania 3.0
H12M1 Kenya 3.2
UH5354 Uganda 3.2
Commercial Check 3.7
MLN scores (on a 1-5 scale basis; 1 being highly resistant to 5 being highly susceptible)
Some CIMMYT-derived MLN tolerant hybrids under NPTs in 2013/14 and MLN score

8. Some NPT hybrids, Naivasha 2014
No complete resistance,
but there is difference in
degree of tolerance

9. Hybrid Yield, t/ha
UH5354* 9.5
Company hybrid 1 9.4
Company hybrid 2 9.4
Company hybrid 3 9.2
Company hybrid 4 9.0
Company hybrid 5 8.9
Company hybrid 6 8.9
Company hybrid 7 8.9
Company hybrid 8 8.9
* MLN tolerant hybrid
In addition to MLN tolerance, MLN tolerant hybrids must be
competitive in other traits

10. In addition to MLN tolerance, MLN tolerant hybrids
must be accepted by farmers for other traits
SATEC- Grain yields Farmers assessments
0
1
2
3
4
5
6
7
8
3.8
6.2 6.6
7.5 7.6
Mean maize grain yield t/ha
Source: THERESIA L.GREGORY –SOCIO ECONOMIST

11. Country Variety Status
Tanzania CKH12613 Farmers assessment/NPT
Tanzania CHMLND0086 NPT and DUS
Kenya CKH12602 NPT2
Uganda CKH12603 Farmers assessment
Kenya CKHMLN146281 NPT1
Kenya CKHMLN146030 NPT1
Kenya CKHMLN146036 NPT1
Kenya CKHMLN146106 NPT1
Kenya CKHMLN146038 NPT1
Kenya CKHMLN146092 NPT1
Kenya CKHMLN146407 NPT1
Kenya CKH13601 NPT1
Kenya CKH13606 NPT1
New hybrids entered NPT in 2015

12. Five hybrids recommended for release/released in KE, UG and TAN
Country Variety Status
Uganda UH5354 Released in 2013/14, already
commercialized
UH5558 Recommended for release in
2014/15
Kenya H12M1 Released in 2013/14, in
commercialization process
H13M2 Recommended for release in
2014/15
Tanzania HB607 Recommended for release in
2014/15

13. CIMMYT supported the release
●Descriptors for NPT hybrids and their
parents
●Parental trials (SC and inbred parents) to
generate information for seed production
●Increase NPT, DUS, breeder/initial and
demo seeds and supply to partners
●Financial support through small grant

14. Seed companies use the information in their seed production
activities

15. Challenges
● Not all the parents of MLN tolerant hybrids are
tolerant/resistant; need MLN free area for seed production
● Need long term breeding to come-up with all parents
resistant to MLN; already on-going
Good to combine tolerant variety + agronomy

16. Thanks!!