Agronomic performance and external and internal appearance of watermelon (Citrullus lanatus) fruit are important traits that should be taken into consideration during the development of a new cultivar, as well as being the principal identification elements used by the consumer, which are based on the external appearance and quality of the fruit. Externally, the fruit can be characterized in terms of the shape, the color of the lower rind, and the presence of grooves and stripes, the stripes can be classified as clearly defined or diffuse.
The olive tree is an iconic tree of the Mediterranean, and is used extensively to produce high-quality olive oil. Although the China olive industry has just begun to be valued, there were also existed mislabeling and synonyms in introduced cultivars. The aim of this study was to analyze genetic similarities among olive cultivars in China using SSR and ISSR techniques. Thirty-two samples were collected from Xichang. Five of these cultivars were issued from a Chinese breeding program.
The genetic diversity and relationship of 42 tomato varieties sourced from different geographic regions was examined with EST-SSR markers. The genetic diversity was between 0.18 and 0.77, with a mean of 0.49; the polymorphic information content ranged from 0.17 to 0.74, with a mean of 0.45. This indicates a fairly high degree of diversity among these tomato varieties.
Pinus massoniana (Masson’s pine) is a widespread tree species in central and southern China and northern Vietnam; it is valued for rosin and paper production. Despite the significant economic value of Masson's pine, little work has been done on its molecular genetics. We developed 318 SSR primers from genome sequences of P. massoniana, and we identified 10 polymorphic markers. The number of alleles in the population of P. massoniana that we examined ranged from two to four, and the Shannon diversity index ranged from 0.150 to 1.133.
Dioscorea cayenensis and Dioscorea rotundata are among the most important yam species for the humid and sub-humid tropics. We isolated nine polymorphic microsatellite markers using a microsatellite-enriched genomic library technique. The nine primer pairs were validated in 22 D. cayenensis accessions, and were tested for transferability in 26 D. rotundata accessions. The number of bands ranged from 2 to 4, with a mean of 3.11. D. cayenensis gave primer polymorphism information content values ranging from 0.37 to 0.62, while for D.
Six F1 populations derived from crosses among 4 orchardgrass (Dactylis glomerata L.) cultivars were studied by morphological and simple sequence repeat molecular markers to test for hybrid vigor and a correlation between genetic distance and heterosis. Heterosis was observed for days to length of culm, leaf traits, tiller numbers, etc. Significant differences between obverse and inverse crosses were found for eleven traits. A cytoplasmic effect existed for the agronomic traits considered in this study.
We examined the genetic diversity of 80 inbred waxy maize lines using 22 SSR molecular markers that could be used to achieve heterosis in waxy maize. Eighty inbred waxy maize lines with different phenotypes, 40 yellow, 25 white, 13 black, and two red lines were analyzed by SSR molecular marker fingerprint and cluster analysis. Using a standard genetic distance of 0.55, the 80 waxy maize inbred lines were clustered into nine groups.
Seventy-seven olive accessions corresponding to 25 cultivars from the Extremadura region of Spain were studied using four microsatellite or SSR markers in order to fingerprint them, and evaluate genetic similarity and relationships between local and introduced olive cultivars. The number of alleles per locus ranged from 4 to 8, with a mean of 6.25 alleles per primer pair (a total of 25 alleles). The observed heterozygosity ranged from 0.58 to 0.95, while the expected heterozygosity varied between 0.68 and 0.83. The polymorphism information content values ranged from 0.63 to 0.79.
Polymerase chain reaction (PCR) is the foundation of SSR molecular marker technology. We used sib rice varieties J518, XD1 and SD23 as experimental materials, selecting 30 pairs of SSR primers, including RM127, RM337 and RM5172, covering the rice genome, and performed single- and double-SSR primer combined analyses. We found that under the same PCR system and conditions, a single primer of the SSR primer pairs could amplify the same fragments as double primers do.
Nine microsatellite loci were isolated from the genome of Laodelphax striatellus (Homoptera: Delphacidae) by constructing (TC)6(AC)5 and (AG)6(AC)5 compound SSR-enriched libraries using suppression-PCR procedures. These loci were found to be highly polymorphic, with 13 to 30 alleles per locus in the three populations that we investigated (Jiangsu, Shandong and Zhejiang). The observed and expected heterozygosities ranged from 0.255 to 0.833 and 0.392 to 0.929, respectively.