Genetic variability of Brazilian rice landraces determined by SSR markers

Abstract

-The objective of this study was to evaluate the genetic variability of rice (Oryza sativa) landraces collected in Brazilian small farms. Twelve simple sequence repeat (SSR) markers characterized 417 landraces collected in 1986, 1987 and 2003, in the state of Goiás, Brazil. The number of landraces with long and thin grain type increased in the evaluated period, probably due to market demand. Based on the molecular data, the genetic variability increased during this period and, as per to the factorial correspondence analysis, most of the accessions were grouped according to the year of collection. The incorporation of modern rice cultivars in landrace cultivation areas and the selection carried out by small farmers are the most probable factors responsible for increasing landrace genetic variability, during the evaluated period. Genotype exchange between farmers, selection practice and local environmental adaptation are able to generate novel adapted allele combinations, which can be used by breeding programs, to reinitiate the process.Index terms: Oryza sativa, genotyping, microsatellites, participatory breeding, rice breeding. Variabilidade genética de variedades locais de arroz determinada por marcadores SSR

Choice of microsatellite markers for isolation of fertility restorers of wild abortive (WA) type cytoplasmic male sterility in rice

“…The range of similarity coefficients (0.0 to 0.5) for pair-wise combinations of the entries indicated a considerably greater extent of variation among the entries and provided greater confidence for the classification of entries and assessment of genetic relationships. Similar inference has been derived in the studies conducted on the molecular markers based differentiation and divergence analysis in rice by earlier researchers (Neeraja et al 2005;Lapitan et al 2007;Herrera et al 2008;Borba et al 2009;Sivaranjani et al 2010;Rani et al 2010;Pervaiz et al 2010;Singh et al 2011;Rathi and Sarma 2012).…”

“…The markers utilized in the present study appeared to be sufficient for discrimination of eighteen entries of rice comprising effective fertility restorers, partial fertility restorers, complete sterility maintainers and weak sterility maintainers. Since the markers were chosen from ten amongst the twelve chromosomes of rice, the levels of diversity exhibited by them seemed to be unbiased and not due to chance (Bajracharya et al 2006;Jaymani et al 2007;Herrera et al 2008;Borba et al 2009;Vanaja et al 2010;Rabbani et al 2010;Singh et al 2011;Rathi and Sarma 2012). So, these markers can be effectively and efficiently utilized for discrimination and unambiguous identification of entries and assessment of genetic diversity in rice.…”

Bayesian analysis of the genetic structure of a Brazilian popcorn germplasm using data from simple sequence repeats (SSR)

“…The presence of private alleles indicates a unique genetic variability at certain loci, and this information is useful for identifying accessions with exclusive genetic variability, the selection of which can increase the allelic richness of gene banks (Borba et al, 2009). The measure Ne is equal to the actual number of alleles if and only if all alleles have the same frequency; if they do not, Ne is smaller (Reif, 2004).…”

Kekerabatan Beberapa Aksesi Padi Lokal Tahan Hama Penyakit Berdasarkan Analisis Polimorfisme Marka SSR

“…Teknologi ini memberikan hasil yang cepat, efektif, akurat, dan telah banyak diaplikasikan pada komoditas padi, di antaranya keragaman 330 varietas tradisional Indonesia (Thomson et al, 2007), keragaman genetik padi lokal (landrace) Brasil berdasarkan marka SSR putatif (Borba et al, 2009), keragaman 96 aksesi plasma nutfah padi terkait umur genjah (Utami et al, 2011), kekerabatan 26 varietas unggul baru asal Indonesia (Susanto et al, 2014), dan keragaman genetik beras berwarna berdasarkan marka terkait sifat warna beras (Kristamtini et al, 2014;Patel et al, 2014;Suzuki et al, 2004;Utami et al, 2009), serta keragaman daun padi liar (Dechkrong et al, 2015). Penelitian ini bertujuan mengetahui kekerabatan dan jarak genetik beberapa plasma nutfah padi lokal yang telah teridentifikasi secara fenotipik tahan terhadap beberapa jenis HPT berdasarkan analisis polimorfisme beberapa marka SSR.…”