Development rate and growth duration of rice (Oryza sativa) in response todelayed transplanting

An experiment was conducted during 1994-95 at Cuttack on the effect of dela yed transplanting on the rate of development and duration of growth in rice (Oryza saliva L.) over 2 sets of seedlings differing in their age at the t ime of transplanting on alluvial soil (haplaquept). Number of days and of g rowing degree-days to reach active tillering, panicle initiation, flowering , milky white grain and 80% panicle ripe were computed. Yield, panicle weig ht and test weight were measured, and straw yield and vegetative growth ind ex were calculated. Correlations were calculated for these values with numb er of days and with number of growing degree-days at each stage of developm ent. In delayed transplanting, significant correlations occurred between yi eld factors and growing degree-days, rate of development and duration of gr owth. Number of days to reach each stage of development was significantly r educed by delayed transplanting, whereas there was no reduction in number o f growing degree-days. On entry mean basis, neither number of accumulated g rowing degree-days nor number of days was correlated with grain yield, stra w yield or test weight. Both the parameters could be useful for predicting rate of development and duration of growth; however, since number of growin g degree-days is less variable throughout the season, its use is beneficial .