45-50 Days to maturity. Brassica oleracea var. alboglabra 'Ryokuho'. Ryokuho Chinese Broccoli Hybrid Seeds. Annual Hybrid. Ryokuho is a cultivar of Chinese Broccoli desirable for its early maturity, vigorous growth, resistance to bolting, and strong heat tolerance. It offers superior performance in its large yields of dark green smooth leafed heads with less wax than other varieties. It also develops shorter petioles and thick stalks compared to similar types of Chines Broccoli. You can enjoy this leafy green in many Asian cuisines both raw or cooked. ~ 2,800 seeds per oz.