Influence of Vernalization and Photoperiod on the Duration of Stem Elongation and Spikelet Fertility in Wheat

Abstract

A longer stem elongation phase (from the terminal spikelet-TS to the anthesis-ANT phases) increases grain production due to an increase in spikelet fertility. However, the mechanism behind the greater number of fertile flowers that occur when the duration of stem elongation is modified by photoperiod and vernalization is not fully understood. The goal of this study was to investigate the effect of combinations of photoperiod and vernalization on the duration of stem elongation and spikelet fertility in wheat. Thus, a greenhouse experiment was performed by subjecting 13 wheat genotypes to two vernalization regimes (V0-non-vernalized plants and V40-plants with 40 vernalization days) and to two photoperiod regimes (NP-natural and NP + 6-photoperiod extended by six hours), during the stem elongation phase. The natural photoperiod increased the spikelet fertility of eight cultivars without a corresponding increased duration of the TS-ANT phase, suggesting the existence of a direct effect of photoperiod on increased spikelet fertility. Vernalization increased the duration of the TS-ANT phase, without influencing spikelet fertility. There was genetic variability in the responses to photoperiod and vernalization.

Cultivation of soybean varieties under cross-seeding system

“…Variety VMAX, which presents an upright set and indeterminate growth habit stood out in the accumulation of fresh and dry mass, with 9.26 and 8.92%, respectively, in the cross-seeding system in comparison to the conventional method. Rodrigues et al (2007) observed higher production of dry mass for denser spacings for the same population of plants. Balbinot Junior et al (2012) obtained contradictory results working with crossed soybean spacing system in Paraná; the largest accumulation of dry leaves, branches and pods per plant was in one with 375,000 seeds ha-1 compared to 562,500 seeds ha -1 , namely conventional and cross-seeding systems, respectively.…”