Variations in rate of leaf emergence, initiation of ear primordium, stem elongation and heading time as affected by vernalization duration of barley with differing growth habits

Abstract

Seven barley varieties were tested in order to observe the effects of vernalization duration (0, 3 or 6 weeks at 4°C) and growth habit on the rates of leaf emergence, shoot apex development, stem elongation and heading time. The rate of leaf appearance was fitted by linear regression, and was constant throughout the period of measurement for the varieties. With increasing duration of vernalization, leaf emergence was more rapid even within the same variety and growth habit. When plants were completely vernalized (6 weeks cold temperature), the development of ear primordia was the same until the initiation of spikelet primordia for all varieties, but thereafter they responded differently. In the case of incomplete vernalization (3 weeks), varieties showed different stages of ear primordium development from 14 days after transplanting. In the non-vernalized plants, spring and facultative or winter types showed two quite different patterns of ear primordium development. The growth rate of stem was constant for any given variety, and ranged from 0.121 to 0.033 mm day −1 . After complete vernalization, the stem grew rapidly and there was no difference between winter and spring types. The start of rapid stem elongation was later for incompletely vernalized plants. Within the same vernalization duration, it was later in winter than in spring types. Within the same growth habit, the onset of stem elongation of early varieties was earlier than that of late varieties. The rates of leaf appearance, ear primordium development and stem elongation were strongly correlated with growth habit.