diversity.html

Crop Diversity

Many of the major crops on which humans depend for food are constituted primarily of cultivars or landraces selected before "modern" agricultural science began. These landraces are usually genetically diverse and in balance with the environment and endemic pathogens. They are dependable and stable in that, although not necessarily high-yielding, they yield something under all but the worst conditions. The conservation and possible utilization of these landraces should be considered a priority in disease management schemes.

The range of diversity in maize

In 1980 I travelled to Mexico with a group of students. On one visit we went to the farm of a traditional farmer near Puebla, Mexico. As the students were talking to him, I noticed a pot containing beans and separated out 17 different types from the pot . Later we found out that they included common beans (Phaseolus vulgaris), lima beans (P. lunatus), and scarlet runner beans (P. coccineus). The farmer said he grew all of them on his 1.5 ha farm. When asked why he grew so many varieties, he noted that some years it was wet, and some years it was dry. Some varieties did better in wet years, and some did better in dry years. Certain years, when insects attacked, some varieties survived while others did poorly. His wife preferred certain varieties for specific cooking purposes. The diversity of his many varieties doubtless gave him some protection against the vagaries of climate and biological sources of stresses. This picutre shows the diversity of the Puebla farmer's beans.

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More traditional agricultural methods :

| Mulching |

| Slash/Mulch | Frijol Tapado / Web Blight |

| Manipulating Shade | Burning | Flooding |

| Multiple Cropping | Using Organic Amendments |

| Rotations | Fallow | Raised Beds |

| Crop Diversity | Storage Practices |

| Multistory Systems |

Comments and suggestions welcomed ...

	Many of the major crops on which humans depend for food are constituted primarily of cultivars or landraces selected before "modern" agricultural science began. These landraces are usually genetically diverse and in balance with the environment and endemic pathogens. They are dependable and stable in that, although not necessarily high-yielding, they yield something under all but the worst conditions. The conservation and possible utilization of these landraces should be considered a priority in disease management schemes.
The range of diversity in maize
In 1980 I travelled to Mexico with a group of students. On one visit we went to the farm of a traditional farmer near Puebla, Mexico. As the students were talking to him, I noticed a pot containing beans and separated out 17 different types from the pot . Later we found out that they included common beans (Phaseolus vulgaris), lima beans (P. lunatus), and scarlet runner beans (P. coccineus). The farmer said he grew all of them on his 1.5 ha farm. When asked why he grew so many varieties, he noted that some years it was wet, and some years it was dry. Some varieties did better in wet years, and some did better in dry years. Certain years, when insects attacked, some varieties survived while others did poorly. His wife preferred certain varieties for specific cooking purposes. The diversity of his many varieties doubtless gave him some protection against the vagaries of climate and biological sources of stresses. This picutre shows the diversity of the Puebla farmer's beans.