Effect of the Duration of the Vegetative Phase on Shoot Growth, Development and Yield in Pearl Millet (Pennisetum americanum (L.) Leeke) uri icon

abstract

  • Craufurd, P. Q. and Bidinger, F. R. 1988. Effect of the duration of the vegetative phase on shoot growth, development and yield in pearl millet (Pennisetum americanum (L.) Leeke).?J. exp. Bot. 38: 124?139The duration of the vegetative phase (DVP) in millet, which is the major cause of variation in the crop duration, has marked effects on the number of productive tillers per plant and on mainshoot (MS) and tiller grain yield. Daylength extensions were used to vary the DVP and the effect on factors affecting panicle (tiller) number per plant and panicle yield examined in millet hybrid 841A × J104, grown in the field at Hyderabad, India. Tiller appearance, shoot leaf appearance and leaf area, and stem and panicle growth, in both MS and primary tillers (PTs), were monitored at frequent intervals over the season. At maturity grain yield per shoot was measuredThe concept of thermal time was used to describe shoot development. The rates of tiller appearance and shoot leaf appearance were linearly related to thermal time and were not affected by DVP treatments. The duration of the growth phase from panicle initiation to flowering (GS2) and from flowering to maturity (GS3) was 320 and 390 degree days (°Cd), respectively. There was no difference in rates of leaf or tiller appearance or development between MS and PTs. Tiller appearance, tiller leaf appearance and tiller apical development all ceased at the same time in the later initiated PTs, approximately 550 °Cd from sowing, shortly after rapid stem growth had begun. Tillers that did not survive were all vegetative or in the early stages of reproductive development at this timeThe rate of accumulation of dry matter per plant was similar in all DVP treatments, but in the longer DVP treatments a greater proportion of the dry matter was partitioned to the MS. Mainshoot stem and panicle growth rates were increased by a longer DVP, as was grain yield on the MS, and these were related to increased MS leaf area. Concurrently, growth rates and yields in later initiated tillers were reduced in relation to their leaf areas. Stem growth rate was proportionately increased more than panicle growth rate in the longer DVP treatments and this, combined with a longer duration of stem growth, resulted in greater stem dry matter at maturity and, therefore, in reduced harvest index

publication date

  • 1988
  • 1988