|Author:||Ray, I. M. ; Segovia-Lerma, A. ; Murray, L. W.|
|Book Group Author:||NA|
Designing effective breeding strategies to integrate selection for carbon isotope discrimination (Δ), as a means to improve alfalfa (Medicago sativa L.) water-use efficiency (WUE), will depend upon the association between Δ and forage yield. The current study was conducted to determine responses in Δ affiliated with significant yield responses that were previously observed among 36 diallel hybrids of nine alfalfa germplasms (commonly referred to as African, Chilean, Flemish, Indian, Ladak, M. falcata, M. varia, Peruvian, and Turkistan). The influence of additive and nonadditive gene action on Δ, and the behavior of Δ across harvests was also determined. Forage yield and Δ of the germplasms and their half-diallel hybrids were evaluated near Las Cruces, NM, during May, June, and July in each of 2 yr in seeded plots that were flood irrigated every 14 d. Values for Δ of hybrids did not significantly exceed those of the most extreme parents in any harvest. Variation for Δ among crosses was attributed primarily to general combining ability (GCA) effects. The magnitude of parental per se and GCA effects, and their ability to predict hybrid Δ varied substantially between the first harvest and later harvests. Variety effects for Δ in Ladak, M. varia, and M. falcata became increasingly negative as the growing season progressed, while those for African, Chilean, Flemish, Indian, Peruvian, and Turkistan increased. Results suggest that fundamental differences in stomatal conductance exist between subspecies sativa and falcata.
|Pages:||1970 - 1975|
carbon, crop yield, diallel analysis, forage, generalcombining ability, genes, genetic variation, germplasm, hybrids,isotopes, leaf conductance, lucerne, plant water relations, selection,stomata, water use, water use efficiency, Medicago, Medicago falcata,Medicago sativa, Medicago varia, Papilionoideae, Fabaceae, Fabales,dicotyledons, angiosperms, Spermatophyta, plants, eukaryotes, Medicago,Medicago sativa, alfalfa, genetic variability, genotypic variability,genotypic variation, Medicago sativa subsp. falcata, Field Crops (FF005)(New March 2000), Plant Breeding and Genetics (FF020), Plant WaterRelations (FF062), Plant Production (FF100)