HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Casler, M. D. Articles by Diaby, M. Search for Related Content PubMed Articles by Casler, M. D. Articles by Diaby, M. Agricola Articles by Casler, M. D. Articles by Diaby, M. Related Collections Germplasm Enhancement Crop Genetics

CROP BREEDING & GENETICS

Positive Genetic Correlation between Forage Yield and Fiber of Smooth Bromegrass

^a USDA-ARS, U.S. Dairy Forage Research Center, 1925 Linden Dr., Madison, WI 53706-1108
^b USDA-ARS, 1575 Linden Dr., Madison, WI 53706-1597

^* Corresponding author (michael.casler{at}ars.usda.gov).

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 reduced bulk volume, measured by neutral detergent fiber (NDF) concentration, have been associated with reduced plant fitness. The objective of this study was to evaluate a second cycle of divergent selection for NDF in four smooth bromegrass (Bromus inermis Leyss.) pedigrees and to determine if concomitant selection for spaced-plant vigor could counteract the loss in forage yield associated with selection for low NDF. In both high and low directions of Cycle-2, populations were created with and without concomitant selection for plant vigor. Selection responses for NDF and forage yield were linear through both cycles of selection in both directions. Although responses were not uniform across the four pedigrees, changes in NDF were reflected in changes in forage yield on all levels evaluated: selection direction (high vs. low NDF), individual cycles, and vigor selections. Although combined selection for low NDF and high vigor improved forage yield in the low-NDF direction for one of four pedigrees, it did not alter the strong positive relationship between NDF and forage yield across all populations and cycles. The genetic correlation between NDF and forage yield appears to be physiological in origin, caused largely by overlapping genic specificities (i.e., pleiotropy).

Abbreviations: C0, Cycle 0 (original populations) • C-1, Cycle 1 low NDF • C-2, Cycle 2 low NDF • C-2V, Cycle 2 low NDF and high vigor • C+1, Cycle 1 high NDF • C+2, Cycle 2 high NDF • C+2V, Cycle 2 high NDF and high vigor • CL, Cycles linear • CQ, Cycles quadratic • CR, Cycles residual • NDF, neutral detergent fiber • P, pedigrees • V, vigor