Phenotypic variation and correlations between monoploids and doubled monoploids of Solanum phureja

Summary Ten anther-derived monoploids, twelve doubled monoploids and the heterozygous anther donor clone of Solanum phureja were compared for six vegetative, eight reproductive and three yield characters in the greenhouse. Significant high correlations were observed between the monoploids and their doubled monoploids for 14 of 17 characters. Therefore, doubled monoploids presumably express the same alleles as monoploids and the phenotypic expression of a monoploid can be used to predict accurately the phenotype of the derived doubled monoploid. Doubled monoploids flowered earlier and had significantly higher values than the monoploids for 15 of 17 characters, indicating a positive effect of increasing gene dosage from monoploid to diploid. Morphological traits can be used to distinguish plants of the two ploidy levels. Significant differences among clones were observed for all parameters within each ploidy level. The anther donor was not significantly different from the mean of doubled monoploids for 10 of 17 characters. For each of 14 characters, some doubled monoploids exceeded the anther donor. Therefore, doubled monoploids which do not express homozygote depression can be obtained.     

Application of random amplified polymorphic DNA to study genetic diversity in Paspalum scrobiculatum L. (Kodo millet, Poaceae)

Summary Genetic diversity and patterns of geographic variation among collections of Paspalum scrobiculatum (kodo millet) and P. polystachyum were studied using molecular markers generated through the random amplified polymorphic DNA (RAPD) method. A high level of polymorphism in RAPD markers was observed among the individual accessions, demonstrating the high genetic diversity of the crop. The markers obtained from the RAPD method were analyzed with the cluster analysis, principal coordinates and minimum spanning tree methods. Three major groups were resolved, one representing the African accessions, and two for the Indian accessions. The accessions of the north African kodo millet and P. polystachyum (considered conspecific with P. scrobiculatum) were quite distinct. The Australian kodo millet showed higher affinity to the African types. The study demonstrated that the RAPD technique can be applied to resolving degrees and patterns of genetic variation at the population and species levels, identifying cultivars, and defining gene pools of this crop.     

Fertility of doubled monoploids ofSolanum phureja

Thirteen anther-derived doubled monoploids and their heterozygous diploid anther donor were evaluated in the greenhouse for flowering, fruit set, seed set and pollen fertility. Doubled monoploids varied for number of days to flower, duration of flowering, abundance of flowers and general flower quality. Fruit set on the doubled monoploids in controlled crosses with diploid male-fertile clones varied from 0 to 73% with a mean of 33% compared to the anther donor with 58%. Seed set varied from 9 to 210 seeds per fruit and was significantly lower than the anther donor (377 seeds/fruit). Five doubled monoploids that shed low quantities of pollen exhibited significantly less pollen stainability (10-30%) than the anther donor (88%). However, pollen of doubled monoploids did not germinatein vitro. 2n pollen frequencies of 20–55% were observed for the doubled monoploids compared with 22% for the anther donor. It was concluded that doubled monoploids had lower female fertility compared to the anther donor but that they produced sufficient seed to facilitate utilization in a breeding program as female parents. However, they were considered to be male-sterile for practical purposes.     

Using a role-playing game to inform the development of land-use models for the study of a complex socio-ecological system

We present an integrated methodology composed of a role-playing game on land adjudication from which we extract narrative and spatially explicit drivers of land-use decisions. We show how geographic information systems (GIS), qualitative decision-matrix analyses, a simple rule-based model using multi-criteria evaluations (MCE), and a machine learning-based land-transformation model (LTM) can be used harmoniously to study complex socio-ecological systems. We evaluate how each technique performs in the study of complex socio-ecological systems using a multi-tier framework detailing how each method analyzes the resource system, resource units, governance system, users and interactions and outcomes in the system. We show that each approach enhances our understanding of the land-use decision making process. Each method provides various information on the drivers of land-use decision, some focusing more on spatial components of socio-ecological systems (resource system and resource unit) and other having a strong emphasis on social mechanisms (governance system, users, interactions and outcomes). Furthermore, we shed light into the existence of a flow of information between the various methods enhancing our understanding of land-use drivers. We end with a discussion on methodological tradeoffs between models and the value of our more holistic approach to modeling land-use drivers and decisions.