Identification and Analysis on True or False Hybrids from Hybridization Populations of Litchi (Litchi chinensis Sonn.) Using EST-SSR Markers.

In order to better distinguish true hybrids in litchi crossbreeding, Fi generations of two litchi hybridized combinations namely that 'Xuehuaizi' x 'Guiwei' and 'Xuehuaizi' x 'Jiaohesanyuehong' were used as materials to identify true hybrids, to construct mapping populations and to study the genetic diversities of the two populations with EST-SSR markers. The results showed that F1 generations of the two hybrid populations could be identified with an identification rate of 100% by the combination of four pair primers, respectively, and the 159 individual plants of the two populations were true hybrids. In addition, variations were exited in leaf morphology of the progenies of the two populations and bands of parents absented were occurred on genotype. The clustering analysis showed that 113 F1 plants from the hybridized combination of 'Xuehuaizi' x 'Guiwei' were clustered into six categories (similarity coefficient was 0.68), and 63. 72% (72 plants) of which clustered into one group with male parent. The genetic distances between 32 plants (28. 3%) and their parents were far which indicated that larger variation or recombinant appeared in these plants. Forty six hybrid progenies of the combination of 'Xuehuaizi' x 'Jiaohesanyuehong' were divided into two categories when the similarity coefficient was 0. 642 and most individual plants (60. 87%) showed closer genetic relationship with female parent and partial maternal genetic tendency. It is concluded that EST-SSR markers are suitable to identify true hybrids of litchi. The construction of the two F1 mapping populations has established basis for further genetic linkage mapping, meanwhile, has accumulated materials for cultivar improvement of litchi. [ABSTRACT FROM AUTHOR]