It is highly single centered with good ring processing characteristics. This hybrid matures at about the same time or a few days earlier than Vaquero. Foliage is heat tolerant and vigorous, and bulbs cure down well with refined and well-finished necks. Granero has outstanding handling and storage quality for a high yielding Spanish type variety. A northern storage type hybrid onion that produces very high yields of uniform, globe-shaped bulbs with bright yellowish brown outer scales that are of medium thickness and very well retained.
Bulbs have firm pungent flesh and are well suited to mechanical handling and long-term bulk storage.
The foliage is very strong and upright with relatively large diameter leaves that tolerate stress very well. SXO 1422 has consistently yielded highest in its class in Sunseeds trials in Michigan, New York, Ontario and Quebec. It also shows promise as a long-storing export type onion for production in Colorado and Washington. It has dark-colored scales that are quite well retained. Madero is primarily adapted for late December through January plantings in California's central valley, and late winter sowings in New Mexico.