Discuss the concept of centre of origin of crops and its role in plant breeding. Describe the role of N. I. Vavilov in identifying centre of origin of various crops with appropriate examples.

Understanding the Concept of Centre of Origin

A centre of origin is a geographical area where a plant species has evolved naturally and where it was first domesticated by humans. These regions possess a high degree of genetic diversity within the species, representing a reservoir of potentially valuable traits for crop improvement. The concept is distinct from a centre of diversity, which refers to a region with a high overall number of plant species, irrespective of their origin.

Role of Centre of Origin in Plant Breeding

The knowledge of crop origins is crucial for plant breeders for several reasons:

• Genetic Resources Acquisition: Centres of origin are prime locations for collecting wild relatives and landraces (traditional varieties) that possess unique genetic traits like disease resistance, drought tolerance, and improved nutritional content.
• Crop Improvement: Wild relatives often contain genes that can be introduced into cultivated varieties through breeding programs to enhance desirable traits.
• Conservation of Biodiversity: Recognizing and protecting centres of origin is essential for conserving the genetic diversity of crop plants, safeguarding them from extinction.
• Understanding Evolutionary History: Studying the genetic makeup of plants from their centres of origin provides insights into their evolutionary history and adaptation mechanisms.

Nikolai Vavilov and His Contributions

Nikolai Vavilov (1887-1940) was a Russian botanist who dedicated his life to studying the origins of cultivated plants. He proposed that cultivated plants originated in eight primary centres of origin, based on geographical distribution, morphological similarities, and archaeological evidence. His work, conducted primarily in the 1920s and 1930s, was tragically cut short by his persecution under Stalin's regime.

Vavilov's Eight Centres of Origin

Centre of Origin	Geographic Location	Major Crops Associated	Significance
1. Near East/Fertile Crescent	Eastern Mediterranean, including Iraq, Syria, Lebanon, Israel, Palestine	Wheat, Barley, Pea, Lentil, Chickpea, Almond	Considered the cradle of agriculture; provided the foundation for many staple crops.
2. Indo-Burma	India, Myanmar, Thailand, Vietnam, Malaysia	Rice, Sugarcane, Mango, Citrus	Rich source of tropical crops; significant for global food security.
3. China/East Asia	China, Korea, Japan	Soybean, Peach, Plum, Pear, Tea	Important for temperate crops and unique agricultural practices.
4. Mediterranean	Southern Europe, North Africa, Western Asia	Olive, Fig, Grape, Pomegranate	Contributed to the development of viticulture and olive oil production.
5. Africa/Ethiopian Highlands	Ethiopia, Sudan, Somalia, Kenya, Tanzania	Coffee, Teff, Sorghum, Millet	Source of many important food crops adapted to arid and semi-arid environments.
6. Mesoamerica	Mexico, Guatemala, Honduras, El Salvador	Maize, Beans, Squash, Avocado, Tomato	Foundation of the Mayan and Aztec civilizations; critical for American agriculture.
7. Andes	Peru, Bolivia, Ecuador, Colombia	Potato, Tomato, Quinoa, Cocoa	High-altitude crops with unique nutritional and adaptive characteristics.
8. Australasia	Australia, New Zealand, Papua New Guinea	Banana, Breadfruit, Taro, Coconut	Important for tropical and subtropical crops; source of unique root crops.

Modern Understanding and Developments

While Vavilov's classification remains a cornerstone, modern molecular genetics and phylogeography have refined our understanding. Genetic analysis has revealed complex patterns of gene flow and introgression (transfer of genetic material between species), blurring the lines between some centres. Furthermore, the concept of secondary gene centres has emerged, where crops have been introduced and subsequently diversified in new regions.

Contemporary Relevance and Conservation Efforts

The ongoing climate crisis highlights the importance of conserving genetic diversity from centres of origin. Climate-resilient varieties often possess traits found in wild relatives. The Svalbard Global Seed Vault in Norway serves as a backup facility for seed banks worldwide, safeguarding crop genetic resources, including those from Vavilov’s identified centres. India’s National Bureau of Plant Genetic Resources (NBPGR), New Delhi, plays a crucial role in collecting, conserving, and distributing plant genetic resources. The National Mission on Sustainable Agriculture (NMSA) includes components for promoting conservation and sustainable use of plant genetic resources.

Case Study: Potato Diversity in the Andes

The Andes region, Vavilov’s seventh centre, remains a hotspot for potato (Solanum tuberosum) diversity. Local farmers have cultivated thousands of potato varieties, each adapted to specific microclimates and possessing unique traits like disease resistance and flavor profiles. The International Potato Center (CIP) in Peru works with local communities to conserve these varieties and utilize them for breeding improved potato cultivars. This exemplifies the ongoing importance of centres of origin for maintaining global food security.