Abstract

Studies predict that wheat production is insufficient for the next generation, and increase yield is an alternative to mitigate. Understand the physiological that determine grain number and especially meanly are required to design new strategies for growing and scientific study. For example, studies postulate that grain weight is controlled and limited by the growth. The objective of this study is to advise a plastic growth in the first stages in starch accumulation, followed by an elastic growth to physiological maturity. Two spring wheat cultivars (Bacanora and Kambara), were sown to field in EEAA (Universidad Austral de Chile), Valdivia, Chile, 2012-2013, under two plant densities (control 370 pl m-2 and low seed rate 44 pl m-2) and distributed in set split split plot design, with three replications. From anthesis on, 4 grains from the four closest positions to the rachis (G1 to G4) of the central spikelets of 4 spikes were collected every 3-4 days in each plot. Grains were measured in length, height, width and calculated volume. In harvest, the method was repeated to 20 grains, collected from 10 spikes. Furthermore, was registering the weight after drying at 60°C during 48 hours. The dynamics were analyzed by 1, 2 and 4 linear regressions with turning points, through the program (Table curve 2D). Curve components were (rates, maximum and times) were recorded and analyzed by ANOVA and Tukey’s test (p < 0.05) was performed. Plastic growth rates of height, width, fresh weight and volume are statistically higher rates of growth plastic, i. e. the width G2 Bacanora plastic growth has a rate of 6.64 um / °Cd and rate plastic growth of 2.52 um / °Cd. Other results and performance are affected and conditioned by genotype and grain position. Acknowledgments to project FONDEF D09I / 1125 and CONICYT scholarship.