Evaluation on Genetic Diversity of Hybrid Parents Developed in Brassic napus

Genetic diversity of 50 Brassic napus varieties including 21 sterile lines, 16 restorer lines and 13 check cultivars was estimated by SSR and ISSR. The UPGMA results showed that 50 Brassica napus varieties were divided into 4 groups. The restorer lines tested were classified into groupsⅠⅢ respectively. The sterile lines tested were classified into groupⅣ. In addition, the sterile lines could be further divided into two subgroups: except 1471AB, all genic male sterile lines were in subgroupⅠ, 1471AB and all cytoplasmic male sterile lines were in the subgroupⅡ. The UPGMA results also indicated that the restorer lines had more genetic diversity than the sterile lines.

Free amino acid (FAA) analysis of phloem sap in hybrid rice Shanyou 63 and its parents

Hyhrid rice has greatly contributed to rice production inChina. But concurrently a dramatic upsurge of rice plant-hopper occurred, particularly for the whitebacked plant-hopper (WBPH), Sogatella furcifera. It has become animportant economic insect pest of hybrid rice, although ithad only been a minor herbivore of rice before nation-wideexploitation of hybrid rice.

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,F1generations of two litchi hybridized combinations namely that‘Xuehuaizi’בGuiwei’and‘Xuehuaizi’בJiaohesanyuehong’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 F1generations of the two hybrid populations could be identified with an identification rate of100%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 F1plants from the hybridized combination of‘Xuehuaizi’בGuiwei’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’בJiaohesanyuehong’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 F1mapping populations has established basis for further genetic linkage mapping,meanwhile,has accumulated materials for cultivar improvement of litchi.

Phenotypic and molecular diversity-based prediction of heterosis in pearl millet(Pennisetum glaucum L.(R.)Br.)

Genetic distances between hybrid parents based on phenotypic traits and molecular markers were investigated to assess their relationship with heterosis for grain and stover yield and other traits in pearl millet(Pennisetum glaucum [L.] R. Br.). Fifty-one hybrids developed using 101 hybrid parents(B and R lines) and showing a wide range of genetic distance between their parents based on eight phenotypic traits and 28–38 SSRs were evaluated in two sets for two seasons. The correlation between Euclidean distance(phenotypic distance, ED) and simple matching distance(molecular distance, SM) for parents of both sets was low but positive and significant(r = 0.2, P < 0.001).The correlation of ED in parents with better-parent heterosis for grain yield was similar in both sets(r =0.38, P < 0.05). SM was not correlated with heterosis for grain yield in either set of hybrids.The results showed that phenotypic distance could be a better predictor of heterosis than molecular distance. The correlation between phenotypic distance and heterosis was not strong enough to permit the use of phenotypic diversity among parents as a major selection criterion for selection of parental lines displaying high levels of heterosis for grain and stover yield in pearl millet.

RAPD-based genetic analysis of offsprings from the sexual cross using allotetraploid citrus somatic hybrid as pollen parent

Thirty-one polymorphic decamer primers were selected to genotype 92 progenies from the cross be- tween Yiben No.4, a monoembryonic diploid F1 hybrid of Citrus reticulata Blanco cv Huanongbendizao tangerine and C. ichangensis Swingle, and [Hamlin sweet orange + Rough lemon], an allotetraploid somatic hybrid of Citrus sinensis Osbeck cv. Hamlin and C. jambhiri Lush cv. Rough Lemon. χ2 (Chi-square) analysis of RAPD markers in the progenies indicated they were randomly transmitted from the four donor parents, without significant difference between the diploids and triploids. However, these progenies were clustered into three major groups using dendrogram constructed by UPGMA, skewed to three parents in certain degrees, 15 (13 triploids and 2 diploids) to Hamlin, 16 (9 and 7) to Yiben No. 4, and 61 (57 and 4) to [Hamlin sweet orange + Rough Lemon] from which genomic contribu- tion was predominant in progenies, respectively.