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Phenotypic characterization of dryland rice (Oryza sativa L.) germplasm conserved in situ (on farm) in a crop-diversity microcenter in southern Brazil

Pinto, Tassiane Terezinha, Ogliari, Juliana Bernardi, Maghelly, Otavio Rechsteiner
Genetic resources and crop evolution 2019 v.66 no.2 pp. 415-427
Oryza sativa, algorithms, arid lands, arithmetics, cluster analysis, cultivars, farms, geographical distribution, germplasm, household consumption, landraces, phenotype, phenotypic variation, progeny testing, rice, rural communities, Brazil
In the far west of the state of Santa Catarina (FWSC) in southern Brazil, rice is produced from landraces grown in a dryland system, with production focused on household consumption. We characterized 60 local landraces of dryland rice and three improved cultivars from EMBRAPA—Arroz e Feijão for phenotypic diversity based on morphological characteristics. The landraces were collected in 27 rural communities of two municipalities in FWSC. Twenty-one morphological groups (MGs) were identified through the use of the Unweighted Pair Group Method with Arithmetic Mean clustering algorithm. Of these 21, 12 were represented by a single landrace. Grain morphology could be used both to distinguish among landraces and to identify different phenotypes within landraces. The geographical distribution of MGs seemed to be completely random. Of the 60 landraces, 35 presented a mixture of characteristics of the Indica and Japonica Groups; 24 presented only characteristics of the Group Indica; and four presented characteristics of Japonica. This finding is intriguing, since rice varieties adapted to dryland agriculture in Brazil generally have genic affinities to the Group Japonica. A clustering analysis based on both qualitative and quantitative characteristics identified four isolated populations and the formation of four groups (cophenetic correlation = 0.82). Some landraces from this study are being subjected to evaluation for their agronomic potential, to be followed by individual selection with progeny testing. This breeding approach is being proposed as a tool to support in situ/on farm conservation of rice landraces in FWSC.