and scientists in subtropical parts'of the US. Tropical hybrids

are now being imported back to the original source of knowledge.

The desirable characteristics of tropical corn are the moderate

yields that can be attained with relatively small amounts of

nitrogen fertilizer, reduced insect, disease, and weed problems,

and reduced grain storage problems in the field and granary. The

most dependable yielder that we've found in this group (recog-

nizing that we haven't extensively tested all tropical hyrids) is

Pioneer brand hybrid X-304C. Years, sowing date, harvest date,

grain yield, and some problems observed in tropical corn are

shown in Table 5.


Table 5. Tropical corn in relation year, sowing date, harvest
date, applied N, water use (water mgt., ppt/irr), grain yield,
and some problems in a low-energy-input system.


Year Sowing Harvest Applied Water ppt/ Grain Problems
 Date Date N Mgt. irr Yield'
 (Ib/A) (in.) (bu/A)


 1985 13 June 23 Oct 120 Dryland 16/0 64 Sidedressed
 late, lodging
 1986 16 June 21 Oct 120 Dryland 25/0 97
 1987 24 June 27 Oct 120 Dryland 15/0 96
 1988 15 June 27 Oct 120 Dryland 23/0 88

 1 Yields with same letter are not significantly different at the
 1 % level of probability.


 Planting sorghum in late May through late July results in

 lower yields, because sorghum is likely to be damaged by midge,

 webworm, and anthracnose during this period (Table 5). Although,

 late July sorghum plantings have been been grown successfully, it

 is best utilized in double-crop systems following temperate corn
 10