ECUADORIAN POTATO LANDRACES: TRADITIONAL NAMES AND GENETIC IDENTITY

Ecuadorian potato landraces (Solanum tuberosum L.) are an important genetic resource, but they have been poorly described. Simple Sequence Repeats (SSR) markers were applied to 152 landraces to assess the genetic diversity of potatoes collected in three areas of high diversity: the Carchi, Chimborazo and Loja provinces. These SSR markers were previously used in the genotyping of more than 800 European potato varieties. The number of alleles and Polymorphism Information Content (PIC) of the markers found in this study were similar to those in European cultivars; however, the overlap in alleles was small. Based on SSR data, the relationship between local names of landraces and genetic identity showed several landraces with different names but identical molecular profiles. It also showed that landraces with identical names but obvious differences in tuber morphology were almost always genetically different. There was no clear grouping of material collected according to the regions under study that suggests extensive movement of seed potatoes all over Ecuador.

Breeding for nutritional quality and pest resistance: potential of a set of non-commercial tetraploid potato cultivars with purple and red flesh

Potatoes are the most widely cultivated tubers and also a valuable source of nutrients and non-nutrient health-promoting compounds. Cultivars with pigmented skin and flesh are of especial interest due to the presence of high concentrations of carotenoids, anthocyanins, flavonoids and phenolic acids. Several investigations have focused on the characterization of native and wild potato accessions, particularly highly pigmented genotypes in order to broaden the overall genetic variation in terms of commercial and processing aptitude, pest resistance and nutritional quality. However, the incorporation of some of these traits into new breeding lines at the tetraploid level is hampered by the presence of detrimental traits as well as varying ploidy levels. Therefore, a set of ten highly-pigmented tetraploid cultivars (Solanum tuberosum L.) was selected and characterized on the basis of tuber morphology, pest resistance and nutritional related traits in order to select parental lines for breeding. Attractive colors and color patterns with potential for the potato snack industry have been identified. Varying degrees of resistance to Globodera spp. and Phythophora infestans, which are considered major threats for the crop, have been found among the collection of pigmented cultivars. Nutritional quality related parameters including significantly higher levels of phenolic compounds, anthocyanins, carotenoids, vitamin C and micronutrients (Zn and Fe) were found when compared with the commercial cultivars used as checks. These findings could assist in the selection of parents (progenitors) towards the introduction of interesting traits into new potato advanced clones at the tetraploid level, without the problems derived from ploidy levels and non-commercial characteristics.

Variation among Australian accessions of Vigna vexillata for traits of agronomic, adaptive, or taxonomic interest

Variation among 79 accessions of Vigna vexillata was evaluated for a range of traits of potential agronomic, taxonomic, or adaptive significance, using potted plants grown in the glasshouse over summer. There was significant variation among accessions for all of the traits evaluated except for tuber morphology. The nature and extent of variation are likely to be of agronomic interest in a plant improvement context. Variation among accessions for quantitatively inherited traits relating to phenology, biomass accumulation (vegetative growth, seeds, and tubers), and pod and seed traits was, in most instances, normally distributed, with no evidence of large discontinuities in response. There was evidence of photoperiodic adaptation among accessions from different latitudes and some interrelations between quantitative traits, for which there were usually plausible physiological explanations. Among the several qualitative traits evaluated, there was evidence of minor linkages between some alleles. There was no evidence of major discontinuities in the observed variation, and no evidence of aggregations of traits into distinctive or geographically discrete morphotypes. It is concluded that V. vexillata is relatively homogeneous across the wide geographical range over which it occurs within Australia.