Relationships among Biomass Yield Components within and between Subspecies of Alfalfa
2004
Riday, H. | Brummer, E.C.
Crosses between Medicago sativa subsp. sativa and subsp. falcata show a heterotic pattern for total biomass yield, with inter-subspecific crosses outperforming intra-subspecific crosses. Little is known about relationships among agronomic traits in sativa-falcata hybrids. The objective of this study was to examine correlations among twenty traits including total biomass yield, total biomass yield heterosis, agronomic traits and forage nutritive value, and genetic distance and test the hypothesis that they differ in intra versus inter-specific crosses. We crossed nine sativa and five falcata genotypes in a diallel mating design. Progeny means of the 91 crosses were calculated based on field data collected in 1998 and 1999 at two locations in Iowa. Most correlations were the same in inter and intra-subspecific crosses, and generally support previous research. Several correlations, however, differed between inter-subspecific and intra-subspecific groupings. Cases where intra-subspecific correlations radically differ from one another may suggest independent suites of alleles in each subspecies controlling traits of interest, especially if no inter-subspecific correlation is present.
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