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Forage quality variation among maize inbreds: Relationships of cell‐wall composition and in‐vitro degradability for stem internodes
Author(s) -
Jung HansJoachim G,
Buxtono Dwayne R
Publication year - 1994
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740660308
Subject(s) - lignin , cell wall , polysaccharide , plant stem , biology , composition (language) , uronic acid , rumen , chemistry , population , genetic variation , botany , zoology , food science , biochemistry , fermentation , linguistics , philosophy , demography , sociology , gene
Forty‐five inbred maize ( Zea mays L) lines were evaluated for genetic variation in stem cell‐wall concentration, composition and degradability, and for relationships among cell‐wall components and polysaccharide degradability. Cell‐wall neutral sugars, uronic acids, Klason lignin, and ester‐ and ether‐linked phenolic acids were measured on lower stem internode samples collected at the time of silking in 2 years. Twenty‐four and 96 h in‐vitro ruminal fermentations were used to determine the rapidly and potentially degradable cell‐wall polysaccharide fractions, respectively. Genetic variation ( P < 0.05) was found for all measures of cell‐wall composition and many estimates of rapidly and potentially degradable cell‐wall polysaccharide components. Inbred line means varied by 50–300% for most traits. Three brown midrib mutant inbred lines included in the study were not the lowest in lignin content nor did they exhibit the greatest cell‐wall degradabilities in this population of inbred maize. Year of growth (environment) influenced ( P < 0.05) cell‐wall traits even though reproductive physiological maturity at sampling was similar in both years. Degradability of the cell‐wall polysaccharide components were intercorrelated ( P < 0.05) within the rapidly and potentially degradable fractions, but rate and extent of degradation of the cell‐wall components were not correlated ( P > 0.05), except for uronic acids. A multiple regression model of principal components (R 2 = 0.41, P < 0.05) indicated that cell‐wall lignification and substitution of wall polymers with phenolic and uronic acids were negatively associated, and pectic substances were positively related with rapid polysaccharide degradation. Very little of the variation (R 2 = 0.15, P < 0.05) in potential cell‐wall polysaccharide degradation could be explained by this multiple regression analysis. There is a large degree of genetic variation among current inbred maize lines for stem cell‐wall quality traits, which should allow improvement of maize as a forage crop. Because of the complex matrix interactions in cell‐wall organization, however, no single cell‐wall component, or simple combination, can accurately predict degradability of maize cell walls.