Pea (Peas, scientific name: Pisum sativum) is a first and second year plant of the legume family. Widely cultivated and edible. Generally, also with peas. Another name (old name) is broad beans. Fruit peas / green peas (called when immature seeds are edible), peas (pods / silk pods, immature pods when edible), yosakumame (in some areas of the northeastern part of the country) How to call) etc. Cultivated species in Japan include Usui pea (light beans), Kinusaya pea, and Dutch pea.
The place of origin is said to be Ethiopia, Central Asia, etc., and it is said to be the oldest agricultural product in the world because it has records in ancient Egypt and ancient Greece. It is a bean cultivated with the origin of wheat farming in the ancient Orient region and the Mediterranean region. The name comes from the fact that it was named "Peas". The original species is presumed to be P. humile Boiss. Et Noö., Which is still wild in the Near East region today. Originally grown as a weed among wheat, this original wild plant is mixed with wheat by discovering its utility value such as edible seeds and seeds and effective soil fertilization by rhizobia. It is thought that the varieties have been gradually improved as cultivated plants since they have been planted and cultivated. At the beginning of farming in this area, common vetch began to be used in the same way as peas, but its cultivation and use was cut off after that, and it is now regarded as a weed. Examples of legumes originating from the same area include broad beans, lentils, and chickpeas. It spread to various parts of Eurasia such as India and China along with wheat cultivation, and was introduced to China in the 5th century and to Japan in the 8th century. It is also known that Mendel used it as an experimental material.
Depending on the hardness of the pods, there are hard pod species (P. sativum subsp. Arvense) (Poir.) And soft pod species (Nankyoshu) (P. sativum subsp. Hortense) (Asch.). As the name suggests, hard pods have hard pods and are mainly used by harvesting fully ripe and dried beans. The flowers are crimson (purple) or white. Soft pods have soft pods, and immature pods are used as peas, and raw beans that have finished growing and are not dried are used as green peas. Snap pea, a variety of peas, has soft pods even when beans grow large, and both beans and pods can be used as vegetables. Green peas are distributed in the market all year round as canned or frozen products, but the raw ones are in season in spring, and the aroma and sweetness are exceptionally good at this time.
Since the place of origin is the Near East region, which has a Mediterranean climate with a lot of rain in winter, the high temperature period in summer is not the optimum period for growth. In northern Tohoku and Hokkaido, where the cold of winter is severe, spring is sown and harvested in early summer. It is vulnerable to continuous cropping, making it difficult to cultivate for several years on land that has been cultivated once. It is also vulnerable to acidic soil, as can be imagined from the fact that the place of origin is a dry area with a large amount of calcium in the soil.
At the time of germination, instead of the hypocotyl extending and developing the cotyledon as a Futaba on the ground like soybeans of the same legume family, only the epicotyl expands and only the true leaf expands on the ground, and the cotyledon is in the ground. Remain in.
Hard pods have been used as dried seeds for a long time, and in Japan, Aoe.