Brassica is a genus in the Brassicaceae family. Plants in this genus include a variety of important agricultural and horticultural crops, including common vegetables such as cabbage and mustard. Species of this genus are native to Western Europe, the Mediterranean region, and temperate regions of Asia. Mainly distributed in the Mediterranean region; China has 13 cultivated species, 11 varieties, and 1 variant, and is cultivated in all parts of the north and south. Basic introduction Chinese name: Brassica Latin scientific name: Brassica Kingdom: Plantaphylum Phylum: Magnoliophyta Class: Dicotyledons Class Magnoliopsida Subclass: Pentaphylla Subclass: Brassicaceae Family: Brassicaceae Family: Brassicaceae Brassica genus: Brassica Distribution area: Native to the temperate regions of Western Europe, the Mediterranean region and Asia. Brief introduction to the current situation, origin, morphological characteristics, geographical distribution, economic value, distribution area, evolutionary trends of main morphological traits, and subordinate classifications , Introduction to current situation Brassica (Brassica) is a cruciferous plant, including many important vegetables, oil crops and feed crops. There are 14 cultivated species of Brassica plants in China, 11 varieties and 1 variant. Later, a wild species was discovered in Xinjiang, named B. xinjian-gensis. Currently, there are 15 species of Brassica plants in China. 11 variants and 1 variant. Origin Species of this genus are believed to have originated in the Mediterranean and the Middle East. my country is the secondary origin and evolution center of cabbage and mustard. However, species of this genus are currently spread all over the world, and many of them have been domesticated and utilized by humans. They are the most economical in the world. A species of value. Morphological characteristics: One-year, two-year or perennial vegetation, hairless or single hairy; roots thin or lumpy. The basal leaves are often rosette-shaped, and the stems are stalked or clasped. The racemes are corymbose-shaped, extending during fruiting; the flowers are medium-large, yellow, with a few white; the sepals are nearly equal, and the base of the inner whorl is sac-shaped; the lateral nectaries are columnar, and the middle nectaries are nearly spherical, oblong or filamentous. Ovary has 5-45 ovules. Siliques are linear or oblong, cylindrical, rarely nearly flattened, often slightly twisted, the beak is mostly cone-shaped, with 1-3 seeds or no seeds in the beak; the fruit petals are hairless, with 1 obvious midrib. Stigma capitate, nearly 2-lobed; septum complete, transparent. Seeds 1 row per cell, spherical or a few ovate, brown, mesh-like: cotyledons folded in half. Geographical distribution Species of this genus are native to temperate regions of Western Europe, the Mediterranean region and Asia. Mainly distributed in the Mediterranean region; China has 13 cultivated species, 11 varieties, and 1 variant, and is cultivated in all parts of the north and south. Economic value: Some species of this genus are used as vegetables. Chinese specialties include mustard, mustard, kohlrabi, and mustard; some species are oil plants, such as rapeseed. Distribution area There are about 40 species of Brassica L plants in the world, including 15 species in China.

Here, the origin, evolution and spread of Brassica plants in China are studied. The results show: (1) The origin of Brassica plants. By comparing the morphological characteristics of Brassica and its outgroup Capparaceae, the Brassica plants in China are divided into three groups: Sect Pekinensis, Sect Juncea, and Sect Oleracea. Among them, the Cabbage group is the most primitive, the Mustard group is more evolved, and the Brassica group is the most evolved; (2) Brassica plants are widespread Distributed in the Yangtze River, Yellow River basins and western mountainous areas of China; (3) There are four distribution pathways for Brassica plants in China. The first one is from the southern Tibetan valley and the northern part of the Hengduan Mountains to the west along the Qilian Mountains in eastern Qinghai and Gansu. The Hexi Corridor, in the Tianshan Mountains of Xinjiang, reaches the mountains on both sides of the Tarim Basin. The second corridor extends from the southern Tibetan valley and the Hengduan Mountains to the northeast, passing through eastern Gansu, Ningxia, northern Shaanxi, Shanxi, northern Hebei, Inner Mongolia and Northeast China. The Greater and Lesser Khingan Mountains are distributed along the Yellow River Basin and the Three Rivers Basin in Northeast China. The third one extends from the southern Tibetan Valley and the Hengduan Mountains to the southeast, passing through Sichuan, Yunnan, Chongqing, and along the Yangtze River Basin, and extends to Guangdong and Taiwan. , the fourth one is along the southern Tibetan valley and the Hengduan Mountains southward to the dry valleys on the north and south sides of the Himalayas. The evolution trend of the main morphological characters of Brassica (1) The entire basal leaves → notched or with small basal leaves Lobe → large-headed pinnae; (2) Petals without obvious claws → with long claws; (3) Petals obovate → obovate or nearly round → broadly oval or oblong; (4) Seeds brown → brown; (5) Pollen The type of pores and grooves is three grooves → three or four grooves; (6) The pattern of the pollen wall changes from reticulate → encephaloid-reticular → cave-reticular; (7) The pollen shape changes from long globular → long globular or oblate globular → nearly globular Or spherical; (8) Annual herb → biennial herb; (9) Chromosome number n= 8, 9, 10 → n = 17, 18, 19; (10) The top of the inflorescence forms a corymb shape → no corymb shape; ( 11 ) The leaves of the plant are pubescent → pubescent; (12) Stem leaves are stalked → stalkless → semi-clasping or fully clasping the stem; (13) Seeds are spherical → convex spherical or ovate; (14) Siliques are not Shrink into a rosary shape → shrink into a rosary; (15) The seeds have obvious holes near the hilum → no obvious holes. Subordinate classification Brassica alboglabra L. H. Bailey Brassica campestris L. Brassica caulorapa Pasq. Brassica chinensis L. Brassica integrifolia (West.) O. E. Schulz Brassica juncea (L.) Czern. et Coss. Brassica napiformis L. H. Bailey Brassica napobrassica (L.) Mill. Brassica napus L. Brassica narinosa L. H. Bailey Brassica oleracea L. Brassica parachinensis L. H. Bailey Brassica pekinensis (Lour.) Rupr. Brassica rapa L.