Gossypium

Lore & Background

The genus Gossypium originated around 5–10 million years ago and is distributed in arid to semiarid regions of the tropics and subtropics. Species are generally shrubs or shrub-like plants, with extraordinary diversity in morphology and adaptation, ranging from fire-adapted herbaceous perennials in Australia to trees in Mexico. Most wild cottons are diploid, but a group of five species from America and Pacific islands are tetraploid, apparently due to a single hybridization event around 1.5 to 2 million years ago. Cultivated cottons are perennial shrubs most often grown as annuals, with broad lobed leaves and seeds contained in a capsule called a boll, each seed surrounded by fibres of two types: longer staples for high-quality textiles and shorter linters for lower-quality textiles.

Reader's Guide

Gossypium has long attracted the attention of scientists due to its immense agricultural, industrial, and trade significance. Cotton is the primary natural fibre used by humans, amounting to about 80% of world natural fibre production, and is also a major oilseed crop and protein source for animal feed.

The genus has been the subject of selective breeding and hybridization to develop varieties with desirable traits such as resistance to insects and diseases and drought tolerance. A public genome sequencing effort began in 2007, focusing first on the D-genome relative G. raimondii due to its smaller size, then the A genome of G. arboreum, to eventually sequence the genomes of cultivated tetraploid cotton varieties. The genus also faces numerous pests and diseases, including the boll weevil, cotton aphid, and various fungal and bacterial diseases, which continue to challenge cultivation.

Did You Know?

• The name Gossypium is derived from the Latin word 'gossypium', which comes from the Arabic 'quṭn' (or 'qutun').
• Cotton fibres occur naturally in colours of white, brown, green, and some mixing of these.
• G. hirsutum accounts for about 90–95% of world cotton production.