Accumulated heat units and phenology relationships in wheat as influenced by sowing dates

A field experiment was conducted to study the influence of sowing dates on phenology and heat unit relationships of wheat. Seeds of BL 1183 and Kancha n were sown on four different dates from November to December (S1, S2, S3 a nd S4). The results indicated that the number of days required to attain di fferent phenological stages, decreased with delay in sowing. For all the ph enological stages, S1 needed higher heat units than that of the other sowin gs. The plants of S1 used heat more efficiently than S2, S3 and S4. At the earlier phenological stages, phenothermal index decreased with delay in sow ing, but increased at the later stages.