Conventional Plant Breeding, mutagenesis, Maize

1. SUCCESSES AND LIMITATIONS OF
CONVENTIONAL PLANT BREEDING
APPROACHES IN MAIZE
BENJAMIN NARH-MADEY
Graduate Research Fellow, Department of Crop Science
University of Ghana
bnarh-madey@st.ug.edu.gh

2. Introduction
• The goal of conventional plant breeding is to produce
crops with improved productivity by altering their genetic
constitution.
• Genetic improvement is driven by natural selection to
favor plants that can compete with other plants and weeds
for nutrient, light, water etc. (Darwin, 1987).
• Plant breeders aid the process of natural selection to
generate high yielding and more nutritious modern crop
varieties.

3. Conventional breeding approaches
Goredema-Matongera et al., 2021

4. Need for conventional maize breeding(CMB)
https://doi.org/10.1016/j.molp.2020.12.00
6
https://www.quora.com/Why-shouldnt-scientists-intervene-
with-natural-selection

5. Conventional Maize Breeding
• Earlier maize breeders improved productivity through
phenotypic selection.
Ahmad et al., 2020

6. Typical conventional
breeding pipeline
Success demands greater
understanding of the
complex biology of
quantitative traits and a
thorough evaluation of
the broader genetic base
of maize.
•DOI: 10.1007/978-3-319-22521-0_5

7. Successes of maize breeding; exploiting wild
germplasms
• Future improvements will require effective utilization of
genetic resources including direct selection upon genotype.
Chen et al., (2020)

8. Successes of CMB; developing hybrid varieties.
Jankowicz-Cieslak et al., 2017

9. Successes of CMB; developing drought tolerant
varieties.
Liu & Qin, (2021).

10. Limitations of Conventional Maize Breeding
Due to;
• Increasing population
• Decline in agricultural resources like land and water
• Decreasing yield curve of staple crops
• Climate change exceeding 1.5°- 2° by end of 21st
century (IPCC, 2021).

11. Limitations of CMB; key demerits
• Limited to exchange between closely related species.
• No surety of any specific gene combinations among
crosses generated.
• Transfer of both desirable and undesirable traits to
progeny
• Time and cost constraints.

12. Limitations of CPB; rice in perspective.
http://b4fa.org/bioscience-in-brief/plantbreeding/how-do-you-develop-a-
new-crop-variety-by-conventional-breeding-ii/

13. Future prospects; Mixed methods i.e., conventional and
molecular breeding methods?
Ahmad et al., 2020

14. What do you think?