effectively designing field and laboratory studies (e.g. for heritability, inheritance of a trait, combining ability), and evaluating genotypes for cultivar release at the end of the breeding program. Familiarity with computers is important for record keeping and data manipulation. Statistics is indispensable to plant breeding programs. This is because the breeder often encounters situations in which predictions about outcomes, comparison of results, estimation of response to a treatment, and many more, need to be made. Genes are not expressed in a vacuum but in an environment with which they interact. Such interactions may cause certain outcomes to deviate from the expected. Statistics is needed to analyze the variance within a population to separate real genetic effects from environmental effects. Application of statistics in plant breeding can be as simple as finding the mean of a set of data, to complex estimates of variance and multivariate analysis.
BiochemistryIn this era of biotechnology, plant breeders need to be familiar with the molecular basis of heredity. They need to be familiar with the procedures of plant genetic manipulation at the molecular level, including the development and use of molecular markers and gene transfer techniques.
Table 1.2 An operational classification of technologies of plant breeding.
| Classical/traditional tools; e.g. | Common use of the technology/tool |
| Emasculation | Making a completer flower female; preparation for crossing |
| Hybridization | Crossing unidentical plants to transfer genes or achieve recombination |
| Wide crossing | Crossing of distantly related plants |
| Selection | The primary tool for discriminating among variability |
| Chromosome counting | Determination of ploidy characteristics |
| Chromosome doubling | Manipulating ploidy for fertility |
| Male sterility | To eliminate need for emasculation in hybridization |
| Triploidy | To achieve seedlessness |
| Linkage analysis | For determining association between genes |
| Statistical tools | For evaluation of germplasm |
| Relatively advanced tools | |
| Mutagenesis | To induce mutations to create new variability |
| Tissue culture | For manipulating plants at the cellular or tissue level |
| Haploidy | Used for creating extremely homozygous diploid |
| Isozyme markers | To facilitate the selection process |
| In situ hybridization | Detect successful interspecific crossing |
| More sophisticated tools | |
| DNA markers | |
| RFLP | More effective than protein markers (isozymes) |
| RAPD | PCR‐based molecular marker |
| Advanced technology | |
| Molecular markers | SSR, SNPs, ISSR, DART, etc. |
| Marker‐assisted selection | Facilitate the selection process |
| DNA sequencing, NGS | Ultimate physical map of an organism |
| Plant genomic analysis‐ | Studying the totality of the genes of an organism |
| Bioinformatics | Computer‐based technology for prediction of biological function from DNA sequence data |
| Microarray analysis | To understand gene expression and for sequence identification |
| Primer design | For molecular analysis of plant genome |
| Plant transformation | For recombinant DNA work |
| OMICS technologies | For studying various aspects of the entire genome |
| Genome editing | For more efficient manipulation of the genome |
| Genome mapping | For more efficient gene discovery |
Whereas the training of a modern plant breeder includes these courses and practical experiences in these and other disciplines, it is obvious that one cannot be an expert in all of them. Modern plant breeding is more of a team than a solo effort. A plant breeding team will usually have experts in all these key disciplines, each one contributing to the development and release of a successful cultivar. Increasingly important disciplines in plant breeding are computer science, for their role in bioinformatics, big data, and simulations.
1.8 Training of plant breeders
Training of plant breeders is a critical consideration in the strategies for addressing global food security. There is the need to train highly skilled professionals who will lead national agricultural research programs to address critical needs in developing local varieties for agricultural production. The traditional approach was offering scholarships to talented scholars from developing countries to pursue terminal degrees at overseas universities. Some of these scholars did not return to their home countries after training. More importantly, many of those who returned often worked on crops that were not native to their countries during their training. Significant efforts have been made to provide advanced training at the graduate level to scholars at their national universities or international institutes. In 2000, the African Center for Crop Improvement (ACCI) was created at the University of Kwazulu‐Natal, South Africa, in collaboration with Cornell University, for the purpose of training plant breeders for Africa. The initiative was so successful that a parallel program, West Africa Center for Crop Improvement (WACCI) was established at the University of Ghana, Legon, in 2009. The initiative was supported by the Bill and Melinda Gates Foundation, the Rockefeller Foundation, and later by the Alliance for a Green Revolution in Africa (AGRA). These scholars are able to work with African crops during their training, thereby making the transition to professional practice as plant breeders after training seamless (see Box 1.1) (Figure 1.1).
