'Florida XP-7': a yellow shrunken 2 sweet corn hybrid and the male inbred parent 'UFISH 8008'.

摘要

The purpose of this breeding programme was to develop a yellow sweetcorn hybrid adapted to late winter production. Florida XP-7 is a shrunken2 (sh2) hybrid from the cross FAHT32b/FAHT32c and the male parent UFISH 8008. FAHT32b and FAHT32c are selected versions of the inbred Florida 32 with Ht1 conditioned resistance to races 0, 23 and 23N of northern corn leaf blight (Setosphaeria turcica). The male parent is derived from the cross of FA56a and CRSH2-8a. Florida XP-7 is a mid-season hybrid averaging 76 days from emergence to prime maturity, and 55 days to mid-silk. It matures 1 day later than the standard yellow hybrid SS7210. Florida XP-7 has a mean height of 192 cm, some 15 cm taller than SS7210. The ear and husk morphology of Florida XP-7 is similar to that of SS7210 and the standard bicolour hybrids SS8102 and SS8202. However, Florida XP-7 is superior to SS7210, SS8102 and SS8202 in the percentage of ears with incompletely filled tips and for a shorter cob tip length with unfilled kernels. Italso has a significantly wider ear and shorter shank than the two bicolour standards. In replicated trials at two sites in Florida, Florida XP-7 gave mean yields of 561 crates/ha [crate size unspecified], greater than SS8102 but similar but lower to those of SS7210 or SS8201. In screening for disease resistance, SS8202 and Florida XP-7 had a similar response to southern corn leaf blight (Cochliobolus heterostrophus) while only SS8202 was more susceptible to S. turcica. Resistance to common rust (Puccinia sorghi) was significantly lower in Florida XP-7 than in the 3 standards.