Sowing date affects yield components of canarygrass seed

Canarygrass (Phalaris canariensis L.) crops are sown from June to mid-September in the southeastern area of the province of Buenos Aires, Argentina. Sowing dates in this range result in different growing temperatures and photoperiods that affect the duration of developmental stages biomass production, and seed yield and its components. For Argentina, there are no reported studies that address these effects. This study on the effects of sowing date was conducted during four growing seasons (1996-1999) at the Instituto Nacional de Tecnologia Agropecuaria (INTA) Experimental Station at Balcarce, Argentina, using a population provided by Dr. Jaime Lloveras, University of Leyda, Spain. Different seeding dates were chosen from June to mid-September. The experiment was a randomized complete block design with four blocks. When the sowing date was delayed, total dry matter (DM) decreased. For early sowing dates seed yield was constant, but after 10 August it was reduced by 1.5%. for each day of delay. Earlier sowing increased the duration of pre-anthesis development with greater uniformity in panicle size and the number of seeds. Seed yield was related linearly to the number of seeds and plant dry matter yield (DMY). The rate of progress from emergence to anthesis (1/days from emergence to anthesis) was proportional to the mean photoperiod. Under the environmental conditions in Balcarce, the accumulated required thermal units for anthesis was reduced when sowing was delayed from June to September. This reduction was related to the photoperiod and was estimated as -189.3 growing degree-days per hour of photoperiod increment.