Effect of dates of closing cut on seed yield and seed quality of Stylosanthes guianensis CIAT 184

The aim of this field research was to investigate the effect of dates of closing cut on seed yield and seed quality of Stylosanthes guianensis CIAT 184 at Khon Kaen Animal Nutrition Research and Development Center, during May 2003 to February 2004. A randomized complete block design with four replications was used. Experimental treatments consisted of five dates of closing cut spaced at about 14-day intervals (27 August, 10 September, 24 September, 8 October 2003 and uncut).The results showed that date of closing cut had a significant effect on seed yields and pure germinable seed yields (PGSY) of S. guianensis CIAT 184. Plots closed on 10 September produced the highest seed yield and PGSY (P<0.05) of 564 and 553 kg/ha, followed by plots closed on 24 September and 27 August (422 and 406; 405 and 391 kg/ha). Uncut plots produced low yield and plots closed on 8 October produced the lowest seed yield and PGSY (401 and 388; 365 and 356 kg/ha). There were no significant differences in seed purity percentage, germination percentage and 1000-seed weight among treatments. Among the dates of closing cut studied, forage DM yield and CP yield were subsequently increased as date of closing cut was delayed. Based on this research, it was concluded that early-September was the optimum date of closing cut for S. guianensis CIAT 184 cultivation for seed production in Northeast Thailand