Assessing and overcoming genetic trade-offs in breeding grazing-tolerant lucerne
L. Pecetti A B and P. Annicchiarico AA Council for Agricultural Research and Economics – Research Centre for Fodder Crops and Dairy Productions (CREA-FLC), Lodi, Italy.
B Corresponding author. Email: luciano.pecetti@crea.gov.it
Crop and Pasture Science 68(11) 952-957 https://doi.org/10.1071/CP16422
Submitted: 9 November 2016 Accepted: 27 March 2017 Published: 15 May 2017
Abstract
Selection of grazing-tolerant lucerne (Medicago sativa L.) for mild-winter environments is challenged by marked cold-season dormancy and prostrate habit often observed in tolerant material. This study aimed to assess the amount of genetic variation and genetically based trade-offs for key traits in four biparental populations, and their implications for selection. Some 432 cloned F1 progenies from four crosses between contrasting genotypes (erect, not very dormant, non-grazing tolerant v. prostrate, dormant, tolerant) were evaluated for dry matter (DM) yield and final plant persistence under continuous, intense sheep grazing for 3 years, along with a set of morpho-physiological traits. Both DM yield and persistence displayed negative genetic correlation with erect plant habit (rg –0.31 to –0.87, depending on the cross), with persistence inversely related also to cold-season growth (rg –0.33 to –0.73). Correlations of performance traits with DM yield before grazing management, plant diameter and leaflet area were inconsistent or nil. DM yield during grazing management and persistence exhibited large genetic variation (CVg 33.3–57.8%), and within-cross variance largely exceeded between-cross variance. Morpho-physiological traits had lower genetic variation and even greater relative within-cross variance than yield and persistence. Selection for grazing-tolerant germplasm could exploit large genetic variation, but it requires extensive within-cross genotype evaluation to produce material with little dormancy and relatively erect growth habit.
Additional keywords: alfalfa, continuous stocking, forage, plant morphology.
References
Annicchiarico P, Pecetti L (2010) Forage and seed yield response of lucerne cultivars to chemically-weeded and non-weeded managements and implications for germplasm choice in organic farming. European Journal of Agronomy 33, 74–80.| Forage and seed yield response of lucerne cultivars to chemically-weeded and non-weeded managements and implications for germplasm choice in organic farming.Crossref | GoogleScholarGoogle Scholar |
Annicchiarico P, Scotti C, Carelli M, Pecetti L (2010) Questions and avenues for lucerne improvement. Czech Journal of Genetics and Plant Breeding 46, 1–13.
Annicchiarico P, Pecetti L, Bouzerzour H, Kallida R, Khedim A, Porqueddu C, Simões NM, Volaire F, Lelièvre F (2011) Adaptation of contrasting cocksfoot plant types to agricultural environments across the Mediterranean basin. Environmental and Experimental Botany 74, 82–89.
| Adaptation of contrasting cocksfoot plant types to agricultural environments across the Mediterranean basin.Crossref | GoogleScholarGoogle Scholar |
Annicchiarico P, Pecetti L, Tava A (2013) Physiological and morphological traits associated with adaptation of lucerne (Medicago sativa) to severely drought-stressed and to irrigated environments. Annals of Applied Biology 162, 27–40.
| Physiological and morphological traits associated with adaptation of lucerne (Medicago sativa) to severely drought-stressed and to irrigated environments.Crossref | GoogleScholarGoogle Scholar |
Bouton JH, Smith SR, Jr (1996) Standard test to characterize alfalfa cultivar tolerance to intensive grazing with continuous stocking. In ‘Standard tests to characterize alfalfa cultivars’. (Ed. CC Fox) p. A-8. (North American Alfalfa Improvement Conference: Beltsville, MD, USA)
Bouton JH, Gates RN, Utley PR (1998) Persistence and yield among nondormant alfalfas selected for grazing tolerance. Journal of Production Agriculture 11, 314–318.
| Persistence and yield among nondormant alfalfas selected for grazing tolerance.Crossref | GoogleScholarGoogle Scholar |
Counce PA, Bouton JH, Brown RH (1984) Screening and characterizing alfalfa for persistence under mowing and continuous grazing. Crop Science 24, 282–285.
| Screening and characterizing alfalfa for persistence under mowing and continuous grazing.Crossref | GoogleScholarGoogle Scholar |
Harvey BM, Widdup KH, Barrett BA (2014) An evaluation of lucerne for persistence under grazing in New Zealand. Proceedings of the New Zealand Grassland Association 76, 111–116.
Humphries AW, Kobelt ET, Bellotti WD, Auricht GC (2006) Tolerance of Australian lucerne (Medicago sativa) germplasm to grazing by sheep. Australian Journal of Experimental Agriculture 46, 1263–1270.
| Tolerance of Australian lucerne (Medicago sativa) germplasm to grazing by sheep.Crossref | GoogleScholarGoogle Scholar |
Lesins KA, Lesins I (1979) ‘Genus Medicago (Leguminosae). A taxogenetic study.’ (Dr W Junk Publishers: The Hague, The Netherlands)
Maureira IJ, Ortega F, Campos H, Osborn TC (2004) Population structure and combining ability of diverse Medicago sativa germplasms. Theoretical and Applied Genetics 109, 775–782.
| Population structure and combining ability of diverse Medicago sativa germplasms.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BD2cvjsV2rtg%3D%3D&md5=2d98770208b549e1f205efb450c1409dCAS |
Pecetti L, Piano E (2005) Heritability of morphophysiological traits and inbreeding effects in grazing-type lucerne. Plant Breeding 124, 176–179.
| Heritability of morphophysiological traits and inbreeding effects in grazing-type lucerne.Crossref | GoogleScholarGoogle Scholar |
Pecetti L, Romani M, Piano E (2006) Persistence of morphologically diverse lucerne under continuous stocking and intensive grazing. Australian Journal of Agricultural Research 57, 999–1007.
| Persistence of morphologically diverse lucerne under continuous stocking and intensive grazing.Crossref | GoogleScholarGoogle Scholar |
Pecetti L, Romani M, De Rosa L, Piano E (2008) Selection of grazing-tolerant lucerne cultivars. Grass and Forage Science 63, 360–368.
| Selection of grazing-tolerant lucerne cultivars.Crossref | GoogleScholarGoogle Scholar |
Piepho H-P, Möhring J (2011) On estimation of genotypic correlations and their standard errors by multivariate REML using the MIXED procedure of the SAS system. Crop Science 51, 2449–2454.
| On estimation of genotypic correlations and their standard errors by multivariate REML using the MIXED procedure of the SAS system.Crossref | GoogleScholarGoogle Scholar |
Popp JD, McCaughey WP, Cohen RDH, McAllister TA, Majak W (2000) Enhancing pasture productivity with alfalfa: a review. Canadian Journal of Plant Science 80, 513–519.
| Enhancing pasture productivity with alfalfa: a review.Crossref | GoogleScholarGoogle Scholar |
Riday H, Brummer EC (2002) Heterosis of agronomic traits in alfalfa. Crop Science 42, 1081–1087.
| Heterosis of agronomic traits in alfalfa.Crossref | GoogleScholarGoogle Scholar |
Rieseberg LH, Archer MA, Wayne RK (1999) Transgressive segregation, adaptation and speciation. Heredity 83, 363–372.
| Transgressive segregation, adaptation and speciation.Crossref | GoogleScholarGoogle Scholar |
Rieseberg LH, Widmer A, Arntz AM, Burke JM (2002) Directional selection is the primary cause of phenotypic diversification. Proceedings of the National Academy of Sciences of the United States of America 99, 12242–12245.
| Directional selection is the primary cause of phenotypic diversification.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD38XntlCks7w%3D&md5=765082659170e0f4e338841e2c8eb446CAS |
Sledge MK, Bouton JH, Kochert G (2003) Shifts in pest resistance, fall dormancy, and yield in 12-, 24-, and 120-parent grazing tolerant synthetics derived from CUF 101 alfalfa. Crop Science 43, 1736–1740.
| Shifts in pest resistance, fall dormancy, and yield in 12-, 24-, and 120-parent grazing tolerant synthetics derived from CUF 101 alfalfa.Crossref | GoogleScholarGoogle Scholar |
Smith SR, Bouton JH, Singh A, McCaughey WP (2000) Development and evaluation of grazing-tolerant alfalfa cultivars: a review. Canadian Journal of Plant Science 80, 503–512.
| Development and evaluation of grazing-tolerant alfalfa cultivars: a review.Crossref | GoogleScholarGoogle Scholar |
