Whole tubers were planted manually. All plants emerged 30 days after planting from
both planting dates. Ammonium mono phosphate (300 kg ha1) and chlorpyrifos
(30 kg ha1) were applied before planting, and 300 kg ha1 of ammonium nitrate after
plant emergence. Standard crop management was applied, involving post-emergence
weeding with linuron and pest control when needed.