七四占是番禺市农科所与华南农业大学农学系、省农科院植保所合作,用(青塘×小香糯)F_4与七加占复交,于1990年晚造选育而成的早籼迟熟新品种.在广东中部种植,早造全生育期约142天,比七桂早迟6天;晚造112-114天,比七桂早迟5-8天.(一)特征特性1992年7月中旬,广东省科委委托华南农业大学邀请有关专家、教授现场观摩评议,一致认为该品种具有如下6大优点.1.优质.据省粮油产品质量监督检查站检定,早造米质为特二级,晚造为特一级,无腹白及心白,煮饭软硬适中,食味较好.2.高产.1991年晚造在番禺市品比试验产量居9个参试优质品种之首,比对照种七桂早增产15.3%,增产极显著;大田示范平均亩产465.8公斤,比七桂 Qisi accounted for Panyu Agricultural Science Institute and South China Agricultural University Department of Agronomy, Provincial Academy of Agricultural Sciences Plant Protection Institute, with (Qingtang × small fragrant waxy) F_4 and seven plus accounted for compound, made in the evening of 1990 made of Early indica late mature varieties .In central Guangdong planting, as early as the whole growth period of about 142 days, seven days later than the six days; late make 112-114 days, seven days later than the 5-8 days. Characteristics In mid-July 1992, Guangdong Provincial Science and Technology Commission commissioned the South China Agricultural University to invite relevant experts and professors to observe and observe the scene and agreed that the variety has the following six major advantages. 1. Quality. According to the provincial grain and oil product quality supervision and inspection station accreditation, as early as the The quality of the second grade, late made as a special grade, no belly white and heart white, moderate cooking soft and hard, better taste .2 high yield .1991 made in Panyu city in the evening than the experimental output of nine parameters The first trial of high-quality varieties, compared with the early varieties of Qiguai 15.3% increase yield significantly; field demonstration average yield per mu 465.8 kg, compared with seven Gui