Genetic variation and heritability of forage yield in Mediterranean tall fescue |
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Authors: | E Piano P Annicchiarico M Romani and L Pecetti |
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Institution: | C.R.A. - Istituto Sperimentale per le Colture Foraggere, viale Piacenza 29, I-26900 Lodi, Italy;;Corresponding author, E-mail: |
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Abstract: | The genetic control of tall fescue forage yield has been poorly investigated. Full‐sib families from diallel crosses of Mediterranean germplasm were evaluated for forage yield over 34 months in a Mediterranean environment with severe drought stress (diallel 1, with 20 parents) and over 16 months under irrigation in a heated greenhouse simulating the Mediterranean temperature pattern (diallel 2, with 15 parents). Genetic parameters were estimated for fresh biomass in diallel 1 and dry‐matter yield in diallel 2. Additive genetic variance was always larger than non‐additive (dominance) variance. Narrow‐sense heritability was fairly high (h2 = 0.61) in diallel 1 and moderate (h2 = 0.45) in diallel 2. Predicted yield gains from one selection cycle were larger in the former diallel (23.9%) than in the latter (10.5%), suggesting that gains can be enhanced by selection under severe drought stress and over a time span sufficient to allow the variation in persistence to fully emerge. General combining ability effects of eight parents that were common to both diallel crosses were highly correlated (r = 0.94) across the contrasting evaluation environments. The extent and consistency of additive genetic effects across environments suggest that rapid improvement of forage yield is possible. |
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Keywords: | Festuca arundinacea additive genetic variance drought stress forage yield germplasm evaluation non-additive genetic variance selection gain |
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