Collection, characterization, evaluation, and utilization of Peruvian peanut landraces

More than 322 landraces of peanut (Arachis hypogaea, L., primarily hirsuta and peruviana varieties) were collected in 1994 and 1995 by a team composed of NCSU and INIA (Peruvian National Institute for Agricultural Research) scientists. Field observations and informal interviews were used to establish passport data on original source. That collection formed the basis for a research project.; Morphological and agronomic data were recorded for 41 variables on a subset of 111 landraces grown at three ecologically dissimilar Peruvian locations. Data were subjected to principal component and cluster analyses. The first three principal components accounted for 35.8% of the variation and 44.7% when the data set was reduced to the 30 most important traits. Other than yield-related traits, key variables in these components were seed width and length, weight of 100 seeds, seed coat color type, presence or absence of four-seeded pods, mainstem color and length, number of secondary branches, plant size, pod beak, and weight of 100 pods. The cluster analysis identified seven distinguishable groups by using the average linkage method. The identification of this set of highly discriminative characters will be important for subsequent experiments to evaluate cultivated peanut germplasm collected in this region. Reliable data to deliver peanut information throughout the world can be assembled more economically by applying this smaller number of select characters. Patterns of quantitative genetic variation within the Peruvian peanut germplasm have been identified, and recommendations for future explorations or sampling for a core collection can be based efficiently on this information.; Late leafspot caused by Cercosporidium personatum (Berk. et Curt.) Deighton is one of the most important foliar fungal diseases of peanuts throughout the world, capable of producing substantial yield losses. Several landraces collected in Peru were identified by ICRISAT (International Crops Research Center for the Semi-Arid Tropics) as having moderate to high resistance to this disease. An experiment was carried out on a sample of 14 landraces previously reported by ICRISAT to be resistant to multiple foliar diseases. Because some accessions are phenotypically heterogeneous, seeds were regrouped in accessions with homogeneous coat color. Detached leaf techniques were used to confirm the differences of the rearranged accessions. Based on measures of sporulating lesion size and number, genotypic responses to late leafspot ranged from susceptible to highly resistant. A subset of these landraces was crossed with N92020, a breeding line selected for high yield at NCSU. Half-sib families were produced to recombine resistance and adaptability genes from the Peruvian parent, with high quality genes from N92020. A group of 102 F{dollar}sb2{dollar}-derived families and their 20 parents were grown with other Peruvian landraces for two years in two ecologically distinct Amazonian regions of Peru. Yield-related traits and late leafspot resistance were analyzed using a statistical mixed genetic model. There was significant variation among parental genotypes and families. In greenhouse facilities and field experiments, resistance was evaluated on a different set of landraces. In both cases different levels of resistance were identified which should have future value in plant improvement programs for peanut.