DURATION OF THE REPRODUCTIVE STAGE AND THE GRAIN YIELD OF WHEAT

Abstract

This work evaluated the effect of temperature and photoperiod on reproductive period duration and their relationship with yield, and
yield components, in eight wheat genotypes (Triticum spp.). Three planting dates at 30 d intervals of were established, from the 16 November 16 2001 to January 15 2002. The length in days from floral initiation to terminal spikelet initiation (early reproductive stage), and
from initiation of the terminal spikelet to anthesis (late reproductive stage), and the effect of the duration of these stages on yield and its
components were evaluated. The last planting date (January 15), reported the smallest duration in the biological cycle until physiologic
maturity, while the first date produce the biggest duration. The third planting date gave the smallest grain yield per ha, mainly duct the
smallest grain size, lesser spikelets per spike and less amount of grains in distals flowers. In general, the genotypes with the shortest
duration of the early reproductive stage presented the highest yields. The most important correlations (r ≥ 0.70) between duration of reproductive stages and yield occurred at the late reproductive stage (r = 0.73), because the number of distal grains increased as the stage
duration increased (r = 0.70). In turn this led to an increasing number of grains per spike (r = 0.79).