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Genetic Variability in Acid Detergent Fiber, Crude Protein, and Their Association with Some Morphological Characters in Smooth Bromegrass 1
Author(s) -
Tan WaiKoon,
Tan GeokYong,
Walton P. D.
Publication year - 1978
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1978.0011183x001800010031x
Subject(s) - biology , bromus inermis , diallel cross , forage , neutral detergent fiber , heritability , genetic variation , genetic correlation , zoology , botany , agronomy , horticulture , gene , genetics , hybrid
A seven × seven half diallel of smooth bromegrass Bromus inermis Leyss., including parental clones, was evaluated for acid detergent fiber (ADF) and crude protein (CP) of whole forage at two harvests and of leafblade, leaf‐sheath, and stem sampled before the first harvest. The objectives were to assess the genetic variability for the quality components, and to examine the associations between the two quality components and some morphological characters. The relative magnitude of the variances due to general and specific combining ability indicated that most of the genetic variance appeared to be nonadditive. Neither ADF nor CP showed significant combining ability at the second harvest. The narrow‐sense heritability estimates were quite high for ADF of the leaf‐blade (46%) but were very low for ADF and CP of whole forages at both harvests (3 to 8%) and for ADF of other plant fractions (0 to 19%). The nature of the genetic variances for ADF and CP suggested that more complicated breeding methods would be necessary for quality improvement. Acid detergent fiber of the leaf‐sheath and stem was closely associated with whole forage ADF (r = 0.70 and 0.84). High correlations were obtained between harvests for both ADF and CP (r = 0.71 and 0.61). ADF increased while CP decreased with increasing plant height and forage yield. Vein frequency was positively correlated with ADF of whole forage (r = 0.41) and leaf‐sheath (r = 0.51). Most phenotypic characters showed little correlation with either ADF or CP at the first harvest.