Commit fe8df9d2 authored by jeremycherfas's avatar jeremycherfas
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New crops added

Banana, barley, beans
parent ce769702
# Apple
## Malus spp.
## *Malus* spp.
Like most fruit trees, selected apple varieties are generally maintained as trees in field collections. [Genesys lists almost 39,000 accessions of various kinds of apple](https://www.genesys-pgr.org/explore/overview?filter=%7B%22taxonomy.genus%22%3A%5B%22Malus%22%5D%7D), including wild relatives that breeders may find useful. About 5% of the accessions are in the form of seeds, but because apple seeds do not breed true, these are not as useful to plant breeders, although they may be of value as reservoirs of diversity. A few samples of apple tissue are cryopreserved in liquid nitrogen.
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Title: banana 01
Author: Jeremy Cherfas
Date: 21 September 2016
Format: snippet
#Banana
##*Musa* spp
Banana is one of the most ancient fruit crops. It originated in Southeast Asia and the Pacific region and is believed to have first been domesticated more than 7000 years ago. East and Central Africa are secondary centres of domestication and diversity.
Most cultivated bananas do not produce seeds, so that accessions have to be preserved as tissue cultures and in field genebanks. [Genesys lists 2,443 accessions][goo]. The vast majority are held at the International Transit Centre in Belgium, with smaller collections in Australia, Nigeria and USA.
Because bananas are multiplied vegetatively, all the individuals in a plantation may be genetically identical clones. This makes banana plantations highly susceptible to outbreaks of pests and diseases. The threat to internationally-traded varieties from new races of pathogen has created worldwide alarm and a drive to breed and engineer resistant varieties. However, the risk is even greater locally in the tropics, where bananas may be the most important staple.
Another target of banana breeding is to create varieties that offer better nutrition. This is especially important where bananas are a staple crop, often used to wean children onto solid food. Efforts are focused on [increasing levels of vitamin A precursors][promusa] to combat deficiency diseases.
Genebank accessions were instrumental in [sequencing the banana genome][cirad], completed in 2012. [Genomic information is available][southgreen] for use by researchers.
About 11% of the accessions listed in Genesys are wild relatives. While the fruit of most of these is inedible, they are very important in efforts to breed new varieties.
[cirad]: http://www.cirad.fr/en/news/all-news-items/press-releases/2012/sequencing-of-the-banana-genome
[goo]: https://goo.gl/bWhDVz
[promusa]: http://www.promusa.org/Vitamin+A+in+banana
[southgreen]: http://banana-genome-hub.southgreen.fr
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Title: barley 01
Author: Jeremy Cherfas
Date: 21 September 2016
Format: snippet
#Barley
##*Hordeum* spp
Barley was first domesticated in the area called the Fertile Crescent, where its wild progenitor *Hordeum vulgare* subsp. *spontaneum* still grows. Other centres of diversity of cultivated barley are found in Ethiopia and Morocco and parts of Asia. Wild relatives are distributed widely in Europe, Asia, Africa and the Americas.
The importance of barley as one of the original staple cereals is reflected in the number of accessions in Genesys: [more than 176,000](https://goo.gl/95A238). Most of the accessions in Genesys are advanced material, including released cultivars and research lines. About 22% are traditional varieties and landraces. Accessions are widely distributed, with the largest collection holding only a third of the listed accessions.
Barley is grown from arctic latitudes to tropical areas and from sea level to high altitudes. In Tibet, Nepal, Ethiopia and the Andes, farmers cultivate barley on the mountain slopes at elevations higher than any other cereals. Barley predominates in the dry lands of North Africa, the Middle East, Afghanistan, Pakistan, Eritrea and Yemen.
With such a widespread distribution, and with diverse uses that include human food, animal feed and as a raw material for alcoholic beverages, barley is the fourth most important cereal in the world.
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Title: beans 01
Author: Jeremy Cherfas
Date: 22 September 2016
Format: snippet
#Beans
##*Phaseolus* spp
Beans of the genus *Phaseolus*, like all pulses, are an important source of protein for many people around the world. In sub-Saharan Africa, more than 200 million people depend on beans as their most important staple. Beans are grown for their green leaves (often fed to livestock), and immature pods and seeds, but it is the dry seeds -- which are nutritious and store well -- that are the primary end product.
The most important crops globally are the common bean, *P. vulgaris*, and the runner or kidney bean, *P. coccinea* with *P. lunatus*, the lima bean, and *P. acutifolius*, the tepary bean, playing a locally important role in the Americas.
Genesys lists almost [109,000 accessions of Phaseolus][goo]: 86% *P. vulgaris*, 4% *P. coccinea*, 6% *P. lunatus* and 1% *P. acutifolius*. About 68% of the accessions are traditional cultivars or landraces, with 15% improved cultivars and 3% wild relatives.
Of the major food crops, beans, and especially common beans, are among the most variable. Growth habit, seed size, shape and colour, days to maturity and many other factors vary across varieties. There is hidden diversity too, not only in resistance to pests and diseases but also in the nutritional value of the seeds. CGIAR Centers, notably CIAT, have been instrumental in [breeding beans that are more productive and more nutritious][cgiar], benefitting millions of households.
{==NB Why are there 4 accessions for Vigna? And 1 of Macroptilium?==}
[goo]: https://goo.gl/hTMS5p
[cgiar]: https://ciat.cgiar.org/crops/bean
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