Pollen Viability and Seed Formation of Autotetraploid Broccoli

Diploid and autotetraploid broccoli plants’ pollen viabilities were studied by using TTC staining,in vitro as well as in situ germination,and their seed formation abilities by orthogonal experimentation.The results showed that: 1) the pollen TTC staining rates of the tetraploid and the diploid were 48.6% and 60.8%,respectively,which were significantly different;2) the in vitro pollen germination rate of the autotetraploid reached a maximum of 66.45% in 4h and leveled off afterward,while that of the diploid peaked at 69.4% in 5h and then leveled off;3) abnormalities were found on the size and germination of the autotetraploid pollen,while those were uniform for the diploid pollen;4) the germination rate of the autotetraploid was lower than that of the diploid broccoli,the pollen tubes of the autotetraploid grew slower with more irregularities than did the diploid broccoli,the in situ germinations of the hybrid and self-bred autotetraploid,as well as,the self-bred diploid were similar,but significantly lower than the diploid hybrids;and 5) the seed formation indices of the hybrid and self-bred diploid were significantly higher than that of the autotetraploid.Through selection process,the seed formation of self-bred autotetraploid was improved by 62.1% in 2009 from 2008.