Study On Flowering Behavior And Crossbreeding Of 8 Alfalfa

The experiment was conduced to study on the flowering behaviors of six Medicago sativa. and two wild Medicago falcata. Then crosses were made between M.sativa and M.falcate. One of the experimental results indicated that there were obvious differences among floret structural characters of 8 alfalfa. Pollen grains collected from 8 alfalfa species were observed by scanning electron microscope. The results showed that there were no obvious differences among the pollen grains in terms of shape, size and surface structures. Pollen grains are long spheroidal, pantoporate. It was found that plants belonging the same family of alfalfa displayed similarities in shape, size and type of surface structures. So pollen morphological characters have little significance in section classification of alfalfa. The quantity characteristics of the inflorescence flowers and pod seeds of 8 alfalfa were studied. The numbers of both inflorescence flowers and pod seeds showed normal distribution patterns which can be represented by some models. A study of 8 Alfalfa species for their flowering habits and daily flowering dynamic changes showed that the flowers of Alfalfa bloomed only in daytime from 6: 00 to 20: 00, while the flowering peak of alfalfa fell on 9: 00- 15: 00. A study of 8 Alfalfa species for their yearly flowering and podding dynamic changes showed that several varities of sativa had obvious flowering peaks, while the others flowered erratically. The pod number of M.sativa kept stabilization when it reached maximum, while M. falcata pod number increased to a peak , keep stabilization for some time then fell rapidly . F1 hybrids from one cross combination of alfalfa, Medicago sativa×Medicago falcata. were studied. Most of F1 hybrids exhibited mid-parent heterosis.