Initiation and development patterns of floral primordia in determinate flowering lines of pigeonpea [Cajanus cajan (L.) Millsp.]

Abstract

The patterns of initiation and development of floral primordia in the determinate flowering pigeonpea lines QPL-2, QPL-3, Bulk, Prabhat and 3D8103, were studied using light and electron-microscopy. The fives lines, sown at Redland Bay, Queensland, (27°37'S) on 26 October, 6 December, 16 January and 1 March, were exposed to natural daylengths of 11.7-14.8 h, an incandescent extended daylength of 16 h and daily air temperatures ranging ll-33°C. Variation in time of floral initiation ranged 23-32 days from emergence in QPL-2 to 26-54 days in 3D8103. Flowering occurred 17-35 days after initiation. In all lines, initiation occurred first at the apices, that of the main stem preceding branch apices, and then basipetally at axillary nodes down the stems. Changes in vegetative morphology and in phenology did not alter the pattern of initiation and development of floral primordia within the plant.