Search Results
Random amplified polymorphic DNA (RAPD) analysis was used to estimate genetic similarities between Portuguese Camelliasinensis (L.) O. Kuntze (tea plant) accessions and those obtained from the germplasm collections from the Tea Research Foundation of Kenya and from the National Research Institute of Vegetables, Ornamental Plants, and Tea of Japan. The accessions studied are taxonomically classified as C. sinensis, var. sinensis, var. assamica, or ssp. lasiocalyx. A set of 118 ten-base arbitrary primers was tested, of which 25 produced informative, reproducible, and polymorphic banding patterns. These primers were used to amplify DNA from 71 tea plant accessions and produced a total of 282 bands, of which 195 were polymorphic. The phenotypic frequencies were calculated using Shannon's Index and employed in estimating genetic diversity within tea plant populations. Our study demonstrates that tea plant populations, including the Portuguese tea plants, show considerable genetic variability. From the UPGMA cluster analysis based on a matrix using the Jaccard coefficient, it was possible to distinguish the Portuguese tea plants from the remaining accessions. The RAPD markers discriminated the three C. sinensis varieties. Moreover, within each variety cluster, subclusters formed according to geographic distribution. The RAPD analysis also separated the commercially cultivated tea plants from the Taiwanese wild tea plants. The present results show that RAPD analysis constitutes a good method to estimate genetic diversity within C. sinensis, and to differentiate C. sinensis accessions according to taxonomic variety and geographical distribution.
Potato seed production by conventional methods represents a sizeable investment that, when passed on to farmers, can decrease their profit margins. Potato minitubers produced by aeroponic systems are space- and cost-efficient, and they also provide healthy propagules to be used by farmers. We evaluated the effects of different misting nozzle types, with and without an antidrip feature, and spray direction on potato minituber yield using the Federal University of Viçosa (UFV) Aeroponic System. Potato plants (cv. Agata) propagated from sprouts were grown in a covered, high-density 100-L polyethylene bucket. The experiment was set up in a randomized complete block design with four replicates and eight treatments combining misting nozzle types (Fogger, MA-30, and CoolNet) with and without antidrip and comparing upward with downward spray directions. Plants were evaluated weekly from 33 to 68 days after transplant (DAT). The parameters used to evaluate treatments were number and mass of minitubers as a function of harvest times, dry mass of roots, stems, leaves, and total biomass. The number and fresh weight of minitubers, as well as root dry weight, stems, leaves, and total biomass were affected by misting nozzle types and spray direction. Treatments also affected biomass partitioning of roots, stem biomass, and the shoot:root ratio. There was also an effect of harvest time on the number and fresh weight of minitubers for various combinations of misting nozzle type and spray direction, except for minituber number with the CoolNet misting nozzle without antidrip and downward spray direction. On the basis of the assessed parameters, the best minituber production system was achieved with the Fogger spray combined with no antidrip, a rate of 12 L·h−1, and with the downward spray direction. The UFV Aeroponic System produced an average of 491 minitubers per plant. This system is simple to implement and may lead to a more affordable upscaling of potato seed minituber production.
The chilean strawberry displays high fruit quality and tolerance to abiotic and biotic factors. Additionally, this species has a rich cultural history going back for at least several thousand years in association with aboriginal people activities and continues at a reduced level today. After its introduction to Europe during the 18th century, it formed an interspecific hybrid to become the maternal species of the commercial strawberry, Fragaria ×ananassa Duch. The objectives of the current investigation were to determine the level and patterns of partitioning of intersimple sequence repeat (ISSR) diversity. ISSR markers were used to assess the genetic diversity in 216 accessions of F. chiloensis, which represented the two botanical forms present in Chile [F. chiloensis ssp. chiloensis f. chiloensis and F. chiloensis ssp. chiloensis f. patagonica (L.) Duch.]. Our results showed high genetic diversity at the species level [polymorphic ISSR loci (P) = 89.6%, gene diversity (h) = 0.24 ± 0.17, Shannon's index (S) = 0.37 ± 0.24] and a lower genetic diversity in f. chiloensis than f. patagonica. The analysis of molecular variance (AMOVA) showed a moderate genetic differentiation among accessions (φst = 14.9%). No geographic patterns for ISSR diversity were observed. AMOVA, structure, and discriminant analysis indicated that accessions tend to group by botanical form. The impact of domestication on the genetic structure of chilean strawberry and its application to breeding and conservation are discussed.