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Relationship of developmental morphology and canopy architecture in switchgrass tiller populations to dry matter yield and fiber quality
Abstract
The ability to genetically manipulate dry matter (DM) yield and in vitro DM disappearance (IVDMD) has been demonstrated with switchgrass (Panicum virgatum L.). The objectives of this research were to determine if phenotypic selection for increased DM yield and IVDMD in six switchgrass populations altered relationships of canopy architecture and developmental morphology with DM yield and fiber quality. The study was conducted on a Sharpsburg silty clay loam (fine, smectitic, mesic, Typic Argiudoll) near Mead, NE and on a Webster silty clay loam (fine-loamy, mixed, mesic, Typic Haplaquoll) near Ames, IA during 1993 in a randomized complete block design with four replications at each location. Tiller populations were harvested on 9 June, 19 July, and 27 August at Ames, IA and on 10 June, 27 July, and 26 August at Mead, NE. Tillers were separated into morphological components and combined by primary growth stage, with DM yield and fiber quality determined on the morphological components and on a derived whole-plant basis. Genotype x environment (G x E) interactions occurred for forage yield and tiller density. Additional collared leaves and stem internodes developed in some populations to explain yield increases when tiller densities were similar; however, dry weight contributions of morphological components and canopy traits were stable across environments. Selection for increased DM yield and IVDMD apparently altered morphological changes within the sward, but had no effect on whole-plant fiber quality. True digestibility (TD) was relatively stable across environments, although the leaf blades of the highest ranking population based on TD in a vegetative sward were not higher than the other populations in the reproductive swards. Thus, leaf to stem ratio may have no value for predicting TD at later sward maturities. Phenotypic selection for increased DM yield and IVDMD in selected switchgrass populations induced changes in canopy architecture which helped explain observed genotype and G x E interactions for DM yield and TD of individual morphological components.
Subject Area
Agriculture|Botany|Range management
Recommended Citation
Redfearn, Daren Dean, "Relationship of developmental morphology and canopy architecture in switchgrass tiller populations to dry matter yield and fiber quality" (1995). ETD collection for University of Nebraska-Lincoln. AAI9536623.
https://digitalcommons.unl.edu/dissertations/AAI9536623