Leaf production and growth in Begonia × hiemalis under long and short days

Abstract

Plants of Begonia × hiemalis cultivar ‘Rieger's Schwabenland Red’ were grown in summer and winter under both long and short days, and the rates of leaf appearance and leaf growth were measured at regular intervals. Leaves appearing during short days showed a progressive decrease in size at maturity, but leaves growing actively at the time of transfer from long to short days were almost unaffected by the change in environment. The rate of leaf appearance in long days was similar in winter and summer, but decreased rapidly after transfer to short days. The response to short days was greater in winter than in summer. The implications of these growth responses for the commercial grower are discussed.