Two Measures of Grain Filling in Spring Wheat

Abstract

Grain weight is a component of grain yield and duration of grain filling is a component of maturity. Both are important traits in applied plant breeding and both depend upon the grain filling process. Grain filling has been described by multi-point and two-point curves. Multipoint curves, based on repeated measurements of grain weight during the grain filling period, are much more demanding of labor and laboratory resources than curves based on records of anthesis, maturity, and final grain weight. To evaluate these two methods of measuring grain filling characteristics, we grew II spring wheat cultivars in irrigated and dryland field trials at Saskatoon, SK, Canada in 1989 and 1990. Final grain weight, time to 50% filled, and relative grain growth rate were estimated from logistic curves fitted to grain weights measured twice weekly from anthesis to maturity. Duration of grain filling and average filling rate (harvest grain weight/duration) were estimated from records of anthesis and maturity. Relative grain growth rate was not related to average filling rate (r =-0.01), and was less closely related than average filling rate to harvest grain weight (r 0.08 compared with r = 0.93, P = 0.01). Estimated time to 50% filled was moderately correlated with observed duration (r-0.66, P 0.05) and, compared with observed duration, differences among cultivars were more consistent and less sensistive to environmental influence. Compared with two-point curves, logistic curves provided better estimates of inherent differences in rate and duration of grain filling. However, this advantage does not justify routine use of multi-point curves in plant breeding except where late season stress masks inherent differences in maturity.

Analysis of effects in wheat of high temperature on grain filling attributes estimated from mathematical models of grain filling

“…As they are analogous, values estimated for the three-parameter model of Darroch & Baker (1995) and the ordinary logistic model of France & Thornley (1984) were identical. The simpler two-parameter model of Darroch & Baker (1995) did not fit the data as well as the other four models, possibly because either an inappropriate value was assumed for W o , or because days after anthesis were used instead of growing degree days. No estimates calculated for either of the Darroch & Baker (1995) models are reported here.…”

“…The Gompertz equation involves three parameters but the inflection point does not occur at the halfway point in the growth curve, as occurs with logistic curves (France & Thornley 1984). Two logistic models outlined in Darroch & Baker (1995) were also included in the analysis.…”

Characterization of the rate and duration of grain filling in wheat in southwestern China

“…Generally, stability is defined as one genotype/trait having an unchanged performance regardless of any variation in the environmental conditions. GW has been shown to be a relatively unstable trait, likely due to complex interactions between wheat genotypes and the environment, with both the rate and GFD varying significantly (Cossani et al, 2011;Darroch & Baker, 1995;Dias & Lidon, 2009;Wu et al, 2014). Changes in the relative performances of genotypes grown in different environments indicate that G × E interactions can be major challenges for crop-breeding programs (Mohammadi et al, 2007;Mohammadi & Amri, 2011;Mohammadi & Mahmoodi, 2008;Zobel & Talbert, 1984).…”

The parameters of grain filling and yield components in common wheat (Triticum aestivum L.) and durum wheat (Triticum turgidum L. var. durum)

“…Each 1 o C increase in the main daily temperature above optimum (12)(13)(14)(15) o C) for grain filling, resulted in the decrease of approximately 2.8 mg and 3.1 days in grain weight and grain filling duration [12]. However, genotypic differences among wheat genotypes exist for both the grain filling duration and its rate [13,14] and can be exploited for the purpose of creating high-yielding cultivars. By comparing the variation in different species, a valuable tool in identifying traits has been proven to be useful in plant breeding [15].…”