"The seeds we carried through Shenzhou 13 manned spacecraft this time are alfalfa seeds." Wang Tao, a alfalfa breeding expert and professor of China Agricultural University, said in an interview with reporters on April 26. In the afternoon of that day, the Shenzhou 13 manned spacecraft's return capsule was opened in Beijing. The crop seeds carried by China Agricultural University and other units were successfully out of the cabin. "Relying on the aerospace breeding industry innovation alliance, this time, we carried 21 forage seeds such as alfalfa, oats, Thinopyrum intermedium and red clover, totaling 158 grams." Yang Hongshan, chief expert of the stress resistant forage breeding and utilization team of Lanzhou Institute of animal husbandry and veterinary medicine, Chinese Academy of Agricultural Sciences, said. The seeds "passengers" carrying Shenzhou 13 manned spacecraft this time include not only alfalfa and oats, but also rice, edible fungi, lettuce and other plant seeds. Each unit "Eight Immortals cross the sea and show their magic powers", and one after another provide "good seed at home". "The seeds and purposes carried by each unit are different. Some focus on basic research, while others focus more on variety cultivation." Yang Hongshan said. "After selecting forages such as alfalfa and oats, we will determine the varieties or new lines to be carried according to the breeding objectives, and carefully select each seed to make each seed full without damage, so as to ensure that it can germinate normally after returning to earth from space." Yang Hongshan said. In other words, these seeds are determined through layer upon layer screening and are truly "Heaven selected seeds". For space mutation breeding, carrying a spacecraft to heaven is only the first and key step, and more importantly, the breeding test of returning to the ground after the space trip. "The breeding years of different plants are different from carrying seeds back to planting on the ground to cultivating new varieties. According to the breeding procedure, it takes more than ten years to cultivate a new alfalfa variety. Oats are annual plants, and the time will be reduced by 2-3 years." Yang Hongshan said. It has been 35 years since China first carried out the return satellite space carrying of rice and other crop seeds in 1987. "Space breeding has three unique advantages that cannot be obtained by other means: providing original, safe and independent intellectual property rights of breeding materials and germplasm gene sources, obtaining rare breakthrough excellent new germplasm, and quickly cultivating new varieties with high quality, high yield and disease resistance." Wang Tao pointed out. In Yang Hongshan's view, space mutation has "three treasures", that is, high vacuum, microgravity and space ray. The combined action of three factors can change the genetic genes of seeds. Over the years, space mutation breeding has made important contributions to China's food security, ecological environment construction and many other fields. The cumulative planting and promotion area of new plant varieties such as crops, vegetables, forests and grasses and flowers has exceeded 2.4 million hectares. It is estimated that space mutation breeding has created a direct economic scale of more than 200 billion yuan. "For example, alfalfa has the characteristics of high protein, high yield and stress resistance, which is of great significance to the development of China's animal husbandry industry. At the same time, alfalfa production is also a short board of China's agricultural industry. At present, China imports 1.3-1.5 million tons of alfalfa hay from abroad every year. Carrying alfalfa seeds in cooperation with aerospace engineering is of great benefit to accelerating the process of Alfalfa Breeding in China." Wang Tao said that the aerospace breeding industry innovation alliance is working with breeders to screen out excellent materials needed for production and serve the improvement of the quality of "chips" in the seed industry. Through space breeding, Yang Hongshan's team has successively cultivated three national approved new varieties of "Zhongtian 1, 2 alfalfa" and "Zhongtian 3 miscellaneous alfalfa". So far, aerospace breeding has cultivated more than 200 new varieties of excellent germplasm approved at or above the provincial level, and has successively created a number of high-quality germplasm such as high-quality three-line rice and Dwarf Rice. (Xinhua News Agency)