Identification of Resistant Germplasm to the Bean Common Mosaic Virus - BCMV.

Seventy-two bean cultivars were tested to determine the presence of the dominant «I» gene for systemic necrosis, which determines death of plants affected by necrotic strain of BCMV (Bean Common Mosaic Virus), before systemic chronic infection begins. Plants that show this hypersensitivity reaction neither show mosaic symptoms nor allow the transmission of the virus to the seed. In order to discriminate the bearer materials of the gene "I" the primary leaves of bean plants were inoculated eight days after sowing with a mix of virus strains NL3 and NL4. The reactions evaluated seven days after the inoculation indicated that 65 of these genotypes have the dominant gene of systemic necrosis that confers the dominant type resistance.Made available in DSpace on 2011-04-09T12:16:35Z (GMT). No. of bitstreams: 1 pab11jul92.pdf: 324004 bytes, checksum: c8fcbe4da10293e3e0503fd7a960339d (MD5) Previous issue date: 2001-09-03199

Maize Diversity In Southern Brazil: Indication Of A Microcenter Of Zea Mays L.

‘Microcenters of diversity’ are restricted geographical areas within which a significant diversity of genetic resources is accumulated. Maize genetic variability, one of the largest among cultivated species, particularly in far western Santa Catarina, southern Brazil, has shown a rich store of landraces, conserved on farm by small-scale farmers. Thus, this study aimed to characterize the diversity of Zea mays L. landraces in two municipalities of this micro-region in Santa Catarina, as well as its geographic distribution, developing the census of diversity as a methodological proposal. Diagnosis was made according to the farmers’ knowledge. The field survey was conducted in 70 rural communities involving 2049 farms. The methodology allowed identifying 136 populations of wild relatives, of which some belong to the species Zea luxurians (Durieu and Ascherson) Bird, and 1513 populations of maize landraces, comprising 1078 of popcorn, 337 of common maize, 61 of sweet maize and 37 of flour maize. The identification of 59 morphological groups, the high use, adaptive and agronomic values, and the Shannon index (H′), estimated according to the grain shape (0.79), endosperm type (0.73), size (0.87), color (1.40), and morphological group (3.16), showed at set a considerable diversity distribution conserved on farm in this micro-region. Landrace richness and the presence of wild relative species, associated with the local human activity and sociocultural aspects, allowed to characterize the far western Santa Catarina as a ‘microcenter of diversity’ of Zea mays L. © 2016, Springer Science+Business Media Dordrecht.64468170