Plant Regeneration from Supersweet Maize Protoplasts Derived from Gametophytic Cell Suspensions Callus Initiation,Maintenance and Plant Regeneration from Embryos of Sweet Maize A COMPREHENSIVE EVALUATION OF SOME NEW SWEET MAIZE VARIETIES WITH THE GREY RELATION DEGREE Carbon and nitrogen mineralization of incubated sweet maize Effects of potassium fertilization on yield, quality and sucrose metabolism of sweet maize