Selection Of Parents Of Medicago Hybridization And Analysis Of Growth Superiority In F₁ Seedling Stage

Using heterosis in medicago breeding is an effective way to increase yield and improve quality.The key to heterosis utilization is how to match parents and how to screen hybrid combinations with strong superiority.In this study,45 medicago germplasm materials were used as test materials.The genetic distance between the materials was analyzed by SRAP molecular marker.Combining with the difference of ploidy and fertility,different medicago hybrids with different varieties and different ploidy were prepared.According to the combining ability of yield traits and heterosis of the progenies,the hybrid combinations with strong superiority were screened out,which laid a foundation for breeding new medicago germplasm with high yield and good quality.The main research results are as follows:(1)The parents of the cross combinations were the same in ploidy and the compatibility between tetraploid materials was greater than that between diploid materials;When the parental ploidy was different,the cross combination with diploid material as female parent had higher copulability than the cross combination with tetraploid material as female parent;The hybridization of male sterile female parent is more fertile than that of male fertile female parent.(2)The heterosis of diploid Medicago varia Martin.‘ Caoyuan No.1’ ×tetraploid 10 Medicago falcata L.was the highest;Diploid Medicago sativa L.‘ Xinjiang Daye’ × 7 Medicago falcata L.showed positive heterosis;When the female parent is diploid,the hybrid combination with tetraploid male parent is more heterosis than the hybrid combination with diploid male parent.(3)All the progeny of the hybrids were tetraploid.The hybridization combination tetraploid Medicago varia Martin.‘ Caoyuan No.1’ × 10 tetraploid Medicago falcata L.with far parental genetic distance had higher pod setting rate,seed number per pod and relative seed setting rate,The hybrid progeny of Medicago sativa L.‘ Xinjiang Daye’ × 11 Medicago sativa L.had the highest biomass per plant,The heterosis and general combining ability of the parents were high,Both combinations have the potential to breed high yield hybrid offspring.