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Partial Decomposition of the Genetic Correlation between Forage Yield and Fiber Using Semihybrids
Author(s) -
Casler Michael D.
Publication year - 2013
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/cropsci2013.01.0056
Subject(s) - bromus inermis , heterosis , biology , forage , neutral detergent fiber , agronomy , genetic divergence , genetic variation , genetic correlation , yield (engineering) , zoology , genetics , genetic diversity , population , hybrid , gene , materials science , demography , sociology , metallurgy
Voluntary intake potential of a forage crop is generally considered to be the most important feed characteristic regulating animal performance. Efforts to develop forage crops with increased intake potential have been associated with reduced plant fitness, prompting a need to modify breeding objectives and methods. The objective of this study was to determine if semihyrids could be used to restore all or a portion of the forage yield lost to drift during selection for low neutral detergent fiber (NDF) in smooth bromegrass ( Bromus inermis Leyss.). A total of 48 semihybrids were created by pair crossing within four base (original) populations, four high‐NDF populations, and four low‐NDF populations. Genetic variation declined progressively with increased NDF concentration. Midparent heterosis was positive and significant for four of six semihybrids at the low‐NDF level. Two of these semihybrids also had positive and significant heterosis for NDF, reflecting the typical positive genetic correlation between yield and NDF. However, two of these semihybrids had no heterotic effect for NDF, resulting in partial decay of the genetic correlation due to a combination of linkage and drift acting on alleles that independently control these two traits. Because about one‐third of this genetic correlation is malleable by manipulation of linkage and drift, there is potential to produce low‐NDF smooth bromegrass populations without sacrificing forage yield potential.