Responses of Spring Wheats to Vernalization and Photoperiod¹

Abstract

Spring wheat (Triticum aestivum L. em. Thell.) cultivars from various sources and different maturity classes were analyzed for responses to vernalization and photoperiod. Response measurements were days to heading, number of leaves on the main culm, and number of tillers at time of heading. Seven of 13 spring cultivars responded to vernalization as measured by reduced leaf number at heading, although differences were small. All 13 spring cultivars, plus a semi‐winter and a winter cultivar, headed sooner if vernalized, although the reductions (2 or 3 days) in some of them can probably attributed to slow development during vernalization. Tiller number at heading was reduced in cultivars responding to vernalization. Response to vernalization of spring types appeared unrelated to earliness of maturity under field conditions. All cultivars tested headed earlier with increasing photoperiods in a series of treatments from 9 to 17 hours. Early maturing cultivars responded least to lengthened photoperiods, and late‐maturing cultivars responded most. A highly significant interaction was obtained between the vernalization and photoperiod responses in one cultivar showing small responses to these individual treatments. However, photoperiod alone rather than vernalization appeared to be the primary factor controlling maturity in spring wheats.

Estimation of Genetic Parameters for Maturity and Grain Yield in Diallel Crosses of Five Wheat Cultivars Using Two Different Models

“…Photoperiod responsive genes play a key role in heading time under field conditions in the cultivars that have already been vernalized (Snape et al, 2001). Photoperiod has higher role in flowering of vernalization insensitive spring wheat than that of winter counterparts which respond to photoperiod when their vernalization requirement was fulfilled (Levy & Peterson, 1972;Davidson et al, 1985).…”

The influence of photoperiod on the dry matter production of grasses and cereals

“…Some require a critical minimum (long) photoperiod for the initiation of flowering (e.g. Heide, 1987), whereas others, including the major cereal species, are quantitative long-day plants without a pronounced critical photoperiod (Levy & Peterson, 1972;Rahman, 1980;Davidson et aL, 1985). In the latter group, the initiation of the collar and the spikelet primordia of the future ear are progressively advanced, in terms of the number of leaves initiated as well as time, as photoperiod is increased (Levy & Peterson, 1972).…”

“…Heide, 1987), whereas others, including the major cereal species, are quantitative long-day plants without a pronounced critical photoperiod (Levy & Peterson, 1972;Rahman, 1980;Davidson et aL, 1985). In the latter group, the initiation of the collar and the spikelet primordia of the future ear are progressively advanced, in terms of the number of leaves initiated as well as time, as photoperiod is increased (Levy & Peterson, 1972). There can also be considerable variation amongst the populations, ecotypes or varieties of a single widely distributed species in their responses to photoperiod, indicating the adaptive value of these responses in relation to successful flowering and seed production.…”

Bulk populations in wheat breeding: comparison of single-seed descent and random bulk methods

“…All parents have a spring-growth habit and are photoperiod-insensitive although Pitic 62 has a cold requirement for floral induction (LEVY & PETERSON, 1972;KLAIMI & QUALSET, 1974 From the F2 through Fs generations, rapid generation advance was used to develop populations by single-seed descent (SSD) and by random bulk composites (BP) in the greenhouse. The SSD populations were advanced by taking a single seed from each plant in each generation; the seeds were cornposited and used to produce the next generation.…”