| The present study was conducted to determine forage yield combining ability and heterosis among the nine alfalfa germplasms, African, Chilean, Flemish, Indian, Ladak, M. falcata, M. varia, Peruvian, and Turkistan. Genetic relationships among the nine germplasms were also determined based on Amplified Fragment Length Polymorphism (AFLP) markers. Finally, the value of AFLP marker diversity, general combining ability (GCA), and parental performance per se was investigated for their usefulness in predicting heterosis and hybrid yield performance of tetraploid alfalfa. Combining ability and heterotic patterns for forage yield were determined among the nine germplasms and their 36 diallel hybrids during two years at Las Cruces, NM. Variation among crosses was attributed primarily to GCA effects; however, SCA effects were also significant. The highest yielding hybrids were African × Peruvian, Chilean × Peruvian, and Chilean × Flemish, which yielded similarly to the check cultivars and exhibited significant high-parent heterosis. Peruvian, Chilean and African also exhibited the highest GCA estimates, indicating that they would be useful parents in alfalfa yield improvement based in recurrent selection and hybridization.; Amplified fragment length polymorphism (AFLP) marker diversity was assessed among the nine alfalfa germplasms. Bulked DNA from thirty genotypes within each germplasm was amplified using 34 primer combinations. Analysis of genetic relationships between the germplasm sources for AFLPs produced two clusters, one resembling M. sativa ssp. sativa and the other M. sativa ssp. falcata. Germplasm groupings were also consistent with their respective geographic origins including Africa, Europe, India, Asia Minor, and the old Soviet Union.; Hybrid yield predictions were made using simple and multiple linear regression models including GD, GCA, and variety effect estimates as predictor variables. Regression analyses were conducted separately for M. falcata's hybrids and 28 hybrids involving the other eight M. sativa ssp. sativa germplasms. GCA alone and a multiple regression model including variety effects and GD were the best predictors of M. sativa ssp. sativa hybrid yield. GCA and GD demonstrated significant potential to predict forage yield of M. falcata hybrids. |
