Which of the following is true about quantitative traits in crops?

Quantitative traits in crops are characterized by displaying a measurable range of phenotypic expressions, such as height, yield, or disease resistance, rather than falling into distinct categories. These traits are typically influenced by the additive effects of multiple genes, often referred to as polygenic inheritance, and are also affected by environmental factors. For example, a plant's height can vary gradually and is determined by the combined effects of many genes as well as environmental conditions like soil quality and water availability. This complexity makes quantitative traits crucial in breeding programs aimed at improving crop performance because they provide a continuous spectrum of potential outcomes that can be selected for.

Traits defined by specific categories would instead be classified as qualitative traits, which exhibit distinct phenotypes (e.g., flower color, seed shape) rather than a range. The inheritance of quantitative traits does not follow a simple all-or-nothing pattern; they are influenced by multiple genetic factors working together. While genetic manipulation has advanced significantly, quantitative traits are often more complex to manipulate than qualitative traits because they involve multiple genes and their interactions. Thus, the correct assertion about quantitative traits is that they show a measurable range and are influenced by many genes.