Why yield trait is complex in plant breeding ?

The yield trait in plants is complex in breeding due to its multifactorial nature, involving interactions among numerous genetic, environmental, and physiological factors. This complexity poses challenges for breeders aiming to improve crop productivity.

 

Genetic Variation: Yield is influenced by multiple genetic factors, including genes controlling traits such as flowering time, plant architecture, photosynthesis, nutrient uptake, and stress responses. The genetic basis of these traits is often polygenic, with many genes contributing to yield variation.

 

Genotype-Environment Interactions: Yield is highly sensitive to environmental conditions such as temperature, water availability, soil nutrients, and biotic stresses. Genotype-environment interactions further complicate breeding efforts, as the performance of a genotype can vary across different environments.

 

Trade-offs: Improving one aspect of yield (e.g., increasing grain size) may come at the expense of other traits (e.g., plant height or disease resistance). Balancing these trade-offs requires careful selection and breeding strategies.

 

Complex Traits: Yield is a complex trait influenced by the interaction of multiple underlying traits and pathways. For example, grain yield depends not only on the number of grains per plant but also on grain size, grain filling, and harvest index.

 

Quantitative Nature: Yield is a quantitative trait controlled by many genes with small to moderate effects rather than a few major genes. Identifying and manipulating these genes to improve yield requires sophisticated genomic and statistical approaches.

 

In conclusion, the yield trait in plants is complex in breeding due to the multifactorial nature of its regulation, including genetic variation, genotype-environment interactions, trade-offs, and the quantitative nature of the trait. Addressing these complexities requires interdisciplinary approaches combining genetics, genomics, physiology, and breeding strategies to develop high-yielding crop varieties capable of meeting the challenges of global food security.