Developmental Rates of Wild Oats (Avena fatua) and Wheat (Triticum aestivum)

Abstract

Prediction of the developmental stages of wheat and wild oats would be useful in order to: 1) correctly time the application of herbicides, and 2) accurately schedule research and cultural operations. The Haun developmental scale which numbers leaf development and describes floral development on the main stem of grasses was found to be suitable for describing the development of semidwarf wheat and wild oats in California. Haun developmental rates of wheat and wild oats were similar. Interference by wheat or wild oats in mixed cultures did not change the developmental rate of either species when grown with added nutrients and water. Degree days gave better correlations with development than calendar days when different planting dates, years, and locations were compared. A degree day model with a 5 C base temperature and a second-order polynomial expression gave accurate predictions of developmental stage, which correlated well with field data.

Compensatory Mechanisms Associated with the Effect of Spring Wheat Seed Size on Wild Oat Competition

“…3 and 4). Previous research investigating the competitive interactions between cereals and wild oat has shown strong negative reciprocal effects associated with inflorescence area −1 (Peters, 1985; Morishita and Thill, 1988; Cudney et al, 1989). Our results also demonstrated that the first‐formed yield component was largely responsible for interference effects.…”

“…These components develop sequentially (i.e., in an ontogenic manner) with late‐developing components controlled by early‐developing ones (Adams, 1967; Garcia del Moral et al, 1991; Dofing and Knight, 1992; Garcia del Moral et al, 2003). The reproductive ability of wild oat can also be defined on the basis of the yield component concept since the developmental rates between wheat and this weed have been found to be similar (Cudney et al, 1989).…”

Influence of Time of Emergence on the Growth and Development of Wild Oat (Avena fatua)

“…Analogous to the GDD model for wheat, the daily T max was restricted to 21 C from emergence to the two-leaf stage and to 27 C from the three-leaf stage to flag leaf emergence (Bauer et al 1984). When T min for the day was less than 5 C, it was considered 5 C (Cudney et al 1989). The Tb was set to 0 C (Bauer et al 1984).…”

“…Effective control of wild oat primarily depends on correct timing of chemical applications which, in turn, relies on accurate predictions of wild oat morphological development (Cudney et al 1989). Wild oat biology has previously been studied.…”

“…Miller et al (1982) and Morrow and Gealy (1983) reported means and ranges for wild oat plant height, tillers per plant, seeds per panicle, and days to panicle emergence. Research on wild oat phenology and growth rate has been very limited, and the range for the wild oat phyllochron was vastly different among studies (Ball et al 1995;Cudney et al 1989). None of these studies, however, have investigated the influence of emergence timing on wild oat biology and morphological development.…”