NOVELTY - High-yield corn seed breeding includes soaking ordinary corn seed in 778 diluting liquid, naturally drying, sowing, applying bottom fertilizer comprising nitrogen, sulfur, yellow humic acid, potassium fulvate, trace element and organic material, before sowing, when the seedlings grow 8-10 leaves, applying fertilizer comprising nitrogen, sulfur, amino acid, yellow humic acid, ammonium fulvate, trace element and organic material, when 1-2 ears appear, wrapping each ear with transparent plastic bag for self pollination, harvesting and soaking harvested corn seeds in colchicine diluting liquid.    USE - High-yield corn seed breeding (claimed).    ADVANTAGE - The method increases the yield by 30% and average yield per mu of 250-350 kg.    DETAILED DESCRIPTION - High-yield corn seed breeding comprises soaking ordinary corn seed in 778 diluting liquid for 10-12 hours at constant temperature, naturally drying, applying 40-80 kg/mu bottom fertilizer comprising 16 wt.% nitrogen, 12 wt.% sulfur, 8 wt.% yellow humic acid, 8 wt.% potassium fulvate, 8 wt.% trace element and 12 wt.% organic material, sowing at 2500-3500 seeds/mu, when the seedlings grow 8-10 leaves, applying fertilizer comprising 64% nitrogen, 18% sulfur, 12% amino acid, 8% yellow humic acid, 8% ammonium fulvate, 10% trace element and 8% organic material, when 1-2 ears appear, wrapping each ear with transparent plastic bag for self pollination, harvesting mature 2-4 ears of corn, soaking the harvested corn seeds in colchicine diluting liquid for 6-12 hours at constant temperature, naturally drying, obtaining first generation double-ear corn variety, sowing the first generation double-ear corn seeds, conducting self pollination, harvesting to obtain second generation double-ear corn, sowing the second generation double-ear corn seeds, conducting self pollination, harvesting to obtain third generation double-ear corn, sowing the third generation double-ear corn at an interval of 600 cmx 30 cm, where before sowing, fertilization is conducted using 40-80 kg/mu bottom fertilizer comprising 16 wt.% nitrogen, 12 wt.% sulfur, 8 wt.% yellow humic acid, 8 wt.% potassium fulvate, 8 wt.% trace element and 12 wt.% organic material, when seedling grows 8-10 leaves, applying fertilizer comprising 64% nitrogen, 18% sulfur, 12% amino acid, 8% yellow humic acid, 8% ammonium fulvate, 10% trace element and 8% organic material, when 1-2 ears appear, wrapping each ear with transparent plastic bag, conducting self pollination, harvesting fourth generation double-ear corn, sowing the fourth generation double-ear corn seeds to harvest fifth generation double-ear corn, sowing fifth generation double-ear corn seeds to harvest sixth generation double-ear corn, sowing the sixth generation double-ear corn seeds to harvest seventh generation double-ear corn, and sowing the seventh generation double-ear corn seeds to harvest eighth generation double-ear corn male parent or female parent. The 778 diluting liquid is prepared by adding raw material with 10 times of 100 degrees C water, after 12-24 hours, naturally cooling to normal temperature, adding 5-10 times of 20-30 degrees C warm water and obtaining 778 diluting liquid. The colchicine diluting liquid is prepared by diluting colchicine raw liquid for 500 times at normal temperature.