The document discusses a study on the inheritance of turcicum leaf blight (TLB) in Ugandan sorghum, focusing on the genetic contributions to resistance against this disease. Using various population types and methods including regression analysis, results showed significant differences in severity ratings and estimates of genetic effects related to TLB. The study highlights challenges in sorghum breeding for TLB resistance, including the need for marker-assisted breeding due to the complexity of disease phenotyping.

1. Generation mean analysis for Turcicum Leaf
Blight in Ugandan Sorghum
Mayada M.Beshir, Abdelbagi M. Ali and P. Okori
3rd RUFORUM Biennial, Uganda
September, 2012

2. Introduction

3. Justification
Sorghum produces 70 million
metric tons of grain from 50
million ha of land, globally
(FAOSTAT, 2012).
Expansion of acreage in
Africa increased at about
3.6%/yr, although yields
declined at 1.0%/yr
(FAOSTAT, 2012).
State Of Food Insecurity in the World concludes that
the number of undernourished people in the world
remains high at close to one billion (FAOSTAT, 2012).

4. Sorghum is Africa's contribution to the world's top crop
www.greenstone.org
www.greenstone.org www.harvestchoice.org/production/bioti
c/mapping

5. Exserohilum turcicum
Turcicum leaf bligh t (TLB)

6. Objectives
• To determine the contribution of additive,
dominant and epistatic genetic effects.
• To understand the inheritance of turcicum leaf
blight in sorghum
Hypothesis
• Available sorghum genotypes display variable
resistance against turcicum leaf blight.

7. Materials & Methods

8. Study site
Field & Greanhouse of Makerere University
Agricultural Research Institute Kabanyolo
(MUARIK) in Uganda .
Data analysis
Regression analysis and ANOVA using GenStat
Discovery Edition 12 (Steel and Torrie, 1997).
Inoculum preparation
Fungal materials will be isolated from naturally
infected sorghum in Uganda & sorghum grains
(Martin et al., 2011).

9. Genetic materials
Derived from a cross of MUC007/009 and Epuripuri
and populations included:
1. Mid parent value of the two parents
2. BC1F1 (to Epuripuri)
3. F2
4. F2:3
5. F2:4
Experiment designs
 Field : CRD
 Greenhouse : α - lattice Resistant line to TLB diseases

10.  Genetic ratios were used to calculate the genetics on
the Turcicum leaf blight inheritance among the
developed populations (Bernardo, 2002).
Population type Mean Additive Dominance Epistasis
BC1F1 1 0.5 0.5 0.25
F1 1 0 1 0
F2 1 0 0.5 0
F2:3 1 0 0.25 0
F2:4 1 0 0.125 0
MUC007/009 (R) 1 -1 0 1
Epuripuri (S) 1 1 0 1

11. Results

12.  Generational means of AUDPC, initial and final
severity ratings under the greenhouse conditions.
Population Type No of Plants AUDPC Initial Severity Final Severity
BC1F1 34 2.7 0.1 5.3
F1 101 2.4 0.1 4.6
F2 81 2.2 0.1 4.2
F2:3 68 2.6 0.2 4.4
F2:4 62 2.5 0.2 4.7
MUC007/009 (R) 38 2.5 0.1 4.7
Epuripuri (S) 36 2.6 0.2 4.9
LSD≤ 0.05 0.64 0.41 0.98

13. Generational means of AUDPC, initial and final severity
ratings under field condition during the first rains of 2010.
Population Type AUDPC Initial Severity Final Severity
BC1F1 6.7 0.6 7.8
F1 6.7 0.6 6.2
F2 8.8 0.6 8.6
F2:3 7.2 0.4 7.5
F2:4 8.8 0.4 10.0
MUC007/009 (R) 4.3 0.3 5.3
Epuripuri (S) 9.8 0.4 9.9
LSD≤ 0.05 2.38 0.40 2.86

14.  Estimates of additive, dominance and epistatic effects
using generation mean analysis.
Relative AUDPC
Greenhouse Field
Mean 2.513*** 8.59***
Additive effects 0.043ns 4.14*
Dominance effects - 0.097ns - 2.32ns
Epistasis 0.060ns - 3.80*

15. Outputs

16. Elite lines with resistance to foliar disease
Line 3
MUK60
Line 1
Resistant line to TLB diseases

17. Remaining challenges to sorghum
breeding for TLB disease resistance
1. Resistance scattered within the genome,
therefore we need marker assisted
breeding
2. Phenotyping of the disease is very
complex due to varied symptoms caused
by TLB pathogens

18. Acknowledgement

19. Indeed, if
the 20th century has been the
century of wheat, rice, and maize,
the 21 st could become the century
of sorghum

20. THANK YOU
FOR YOUR
ATTENTION