An enigma in the process of domestication of many of our common vegetables is what they looked like and the speed of the process at which they were transformed from the wild progenitors to the modern cultivars. Many vegetables were either domesticated in antiquity or introduced into Europe, often by trade with Africa, the Middle East, or the Americas. Based on genetic information, we often know or can deduce center of origin and the progenitor species of our common vegetables, but we do not have a record of their early history once introduced into Europe. One window to the process of domestication of vegetables is still life art from the Renaissance period. The emphasis of the art form “natura morta” emphasized realism, which allows us to, in some cases, identify species and market classes based on accurate morphological details.
Jesse Vorwald and James Nienhuis
Nuña beans are a type of common bean (Phaseolus vulgaris L.) from the Andean region of South America that possess the unique property of popping. To develop temperate-adapted nuña bean cultivars, knowledge is needed regarding the inheritance and relationships among popping characteristics and seed weight. Nuña bean landraces are often photoperiod-sensitive; thus, to obtain estimates of the genetic parameters associated with seed characteristics, populations adapted to the long days of northern temperate climates were developed. Four sets of 10 families, sampled from a temperate-adapted population, were crossed in a Design II mating design. The heritabilities of seed weight, popping percentage, and the coefficient of expansion were relatively high, 0.77 ± 0.04, 0.87 ± 0.07, and 0.74 ± 0.09, respectively. Large positive phenotypic (0.773) and additive genetic (0.539) correlations were observed between popping percentage and the coefficient of expansion. Correlations with seed weight were not significant. The results indicate that direct selection for either increased popping percentage or coefficient of expansion will simultaneously improve both traits with little or no change in seed weight.
Jesse Vorwald and James Nienhuis
Nuña beans are a type of common bean (Phaseolus vulgaris L.) native to the Andean region of South America that possess the unusual property of popping; however, little is known regarding postharvest environmental effects on popping. Seed of a photoperiod-insensitive, temperate-adapted nuña bean breeding line, ‘PB24’, was produced at the Arlington Agricultural Research Station, Arlington, WI, and evaluated in a hot air popper. The experimental design was a factorial with three levels of popping time (60, 90, and 120 s), five levels of chamber temperature (101, 146, 208, 244, and 268 °C), and eight levels of seed moisture (2.5%, 3.2%, 5.2%, 6.6%, 8.3%, 12.0%, 15.3%, and 20%). Percentage of popped seed, sufficiently expanded to shed the seedcoat, was calculated. A curvilinear decrease in popping percentage was observed with increasing seed moisture content. In contrast, a curvilinear increase in popping percentage was observed with increasing chamber temperature and popping time. Larger mean squares were observed for main effects and first-order interactions associated with seed moisture content and chamber temperature compared with popping time. A combination of seed moisture below 5%, popping chamber temperature of 244 °C, and popping time of 90 s resulted in popping percentages greater than 90%.
Gavin R. Sills and James Nienhuis
The interactive effects of genotypes, plant population densities, and harvest methods on snap bean (Phaseolus vulgaris L.) yield evaluation were investigated using a split-split plot factorial arrangement of treatments at two locations Six snap bean processing cultivars were grown at 5.5, 11, and 22 plants/m2 and harvested either by machine or by hand. Each' of three commercial seed companies provided two cultivars, one of which was described as “good” and the other as “poor” for machine harvesting. Genotype × harvest method interactions were not significant for pod count, but were significant when yield was evaluated as pod weight. This latter interaction was explained by a single-degree-of-freedom contrast of genotypes × (“good” vs. “poor” harvestability). Genotype × density and genotype × density × location interactions were significant for both pod count and weight. The density × harvest method interaction was nonsignificant for both yield variables. These results suggest that breeders can evaluate yield of genotypes using either hand or machine harvest but should use plant population densities appropriate to commercial production. Optimum plot size for snap bean yield evaluations at these locations under the various conditions imposed were estimated.
James Nienhuis*, Betsy Barnard and Michell Sass
We have developed a series of instructional materials integrating a proven teaching tool, Wisconsin Fast Plants, with hands-on molecular techniques. Many biotechnology techniques, including genomics, have developed to a point where appropriate modifications can result in classroom accessible instructional materials that will engage students and teachers. Three “kits” have been developed or are in the process of development. Kit 1-PCR and Fast Plants. This kit is designed to provide an introduction to PCR and a link to Wisconsin Fast Plants. This kit uses a specific robust primer, which can amplify a specific sequence in Brassica rapa (Fast Plants). This kit serves as a hands-on tool to familiarize students with DNA extraction, PCR, gel electrophoresis, and analysis of PCR products. Kit 2-Genetic Diversity—`Veggie interesting'. This kit is based on the development of a specific primer, which is polymorphic between B. rapa (Fast Plants) and B. oleracea (common vegetables). In this kit, we explore the use of molecular markers and PCR to determine the species classification of various Brassica subspecies. This kit can be used to teach students about plant diversity and the use of molecular biology techniques (such as PCR) to determine how plants are related to each other. Kit 3-Genomics. The primary biological component is a simplified DNA chip (microarray) specifically designed for visualization of differential gene expression. This chip contains Arabidopsis thaliana genes that have already been characterized in our laboratory that display differential expression in seedlings grown in light vs. dark. To simplify analysis, the chip contain approximately ten genes rather than the thousands that are typically spotted on research chip.
James Nienhuis, Steve Schroeder and Gretchen King
An accession of the wild species of tomato, L. pennellii (Cor.) D'Arcy, LA 1077 is much more water-use efficient (WUE) than the cultivated tomato. The F1 hybrid between L. esculentum cultivar UC82 and LA 1077 was backcrossed to UC8 2 and selfed. S1 families (BC1S1) were evaluated for fruit quality characteristics at the Heinz Research Farm, Stockton, CA. Broad sense heritabilities were estimated as follows: Fruit weight, 0.52 ± .28; Soluble solids 0.56 ± .27; viscosity 0.63 ± .27; pH 0.43 ±.29 Color L 0.59 ± .27 and Color A/B ratio 0.50 ± .28. The following phenotypic correlations were observed in the BC1S1 generation between expression of soluble solids and fruit quality characteristics: Fruit weight (g), 0.15; viscosity, -0.65; pH -0.52; Color L, -0.53 and Color A/B ratio 0.02.
James Nienhuis, Paul Skroch and Steve Beebe
Nuñas are a type of common bean (Phaseolus vulgaris) that possess the unusual characteristic of popping or expanding their cotyledonary tissue when heated. Numerous landraces of nuña beans were domesticated in the Andean region of South America (Peru, Bolivia, and Ecuador) and have been grown and consumed in this region since antiquity. The practical consideration in the domestication of nuñas in the high Andes was likely due to the greater energy efficiency in cooking toasted vs. boiled seeds.The Phaseolus germplasm bank at CIAT (Centro Internacional de Agricultura Tropical) has developed a core collection of Andean beans that includes numerous nuña landraces. Based on the wide range of phaseolin types observed among nuña landraces, it has been hypothesized that nuñas may represent a greater source of genetic diversity compared to other landraces and cultivars of common bean. Eighty nuña accessions and 120 nonpopping common bean accessions were randomly sampled from the CIAT Andean germplasm core collection. The 200 accessions were characterized for 140 mapped RAPD markers. The objectives of our research were to 1) understand the genetic structure of nuña bean accessions relative to other Andean common beans, and 2) to measure the genetic distance and genetic diversity between nuña and other Andean bean populations.
Federico L. Iniguez Luy and James Nienhuis
Wisconsin Fast Plants (WFP) are small, rapid-cycling Brassica rapa populations that were developed by Paul Williams in the Dept. of Plant Pathology at the Univ. of Wisconsin, to facilitate classroom demonstration of biological principals. WFP exist as heterogenous populations, which have been selected for expression of different mutant phenotypes. Because of self-incompatibility mechanisms, it has been difficult to develop inbred lines of WFP via self-feritilization. Our objective was to inbreed a WFP population through full-sib mating. Genetic diversity was calculated for eight individuals from each of eight different WFF population, using 69 polymorphic RAPD (molecular marker) bands. The eight different WPF populatons were randomly mated (via chain crossing) for two generations. Six cycles of full-sib mating were initiated on 130 random families. After six cycles of full-sib mating, 79 families remain. The loss of families, during the process of inbreeding, may have been due to selection or drift. However, the expectation is that genetic variance will increase. The 79 inbred families express an array of different WFP phenotypes, e.g., anthocyanin pigmentation, yellow cotyledon, plant height, and seed color at different combinations in different inbred lines.
Edison Miglioranza, Phillip Barak, Kenneth Kmiecik and James Nienhuis
Soils were fertilized with gypsum (CaSO4·2H2O) at rates up to 4 t·ha-1, and Ca2+ concentrations in pods of 12 snap bean (Phaseolus vulgaris L.) cultivars were determined, with the intention of improving snap beans as a source of Ca2+ for human nutrition. The addition of gypsum to the soil did not affect the Ca2+ concentration of pods, even though Ca2+ in the soil solution increased from 4 to 15 mmol·L-1. Calcium concentrations of pods of the various snap bean cultivars ranged from 4.1 to 5.7 mg·g-1 dry mass. `Top Crop', `Astrel', `Tenderlake', and `True Blue' had the highest Ca2+ concentration in the pods and `Labrador' and `Roma II' had the lowest. The results suggest that factors other than Ca2+ supply influenced the Ca2+ concentration of the snap bean pod. Therefore, increased Ca2+ concentration of pods may be better achieved through breeding and selection rather than Ca2+ fertilization when Ca2+ levels in soil are sufficient.
Jan G. Tivang, Neal DeVos, James Nienhuis and Paul Skroch
Individual heads (capitula) from five discrete artichoke, Cyara scolymus L., populations were evaluated using RAPD markers. One vegetatively-propagated cultivar; Green Globe; two seed-propagated cultivars, Imperial Star and Big Heart XR-1; and two breeding populations were examined. Twenty-seven RAPD primers were scored yielding 2 to 16 polymorphic bands resulting in a total of 178 bands. Our objective was to determine if RAPD markers could be used to distinguish between and within populations. The genetic relationships among populations as well as among individuals within each population were estimated using the ratio of discordant to total bands scored. Data reduction (MDS) provided a plot indicating five clusters corresponding to the five populations. Confirmation of the presence of five discrete clusters was obtained by analysis of variance of the marker frequencies. The genetic diversity index (GDI) was calculated for each populations as the pooled variance of band frequency for each population. The GDI values were highly correlated to the mean genetic distance within each population. The homogeneity of variance for the GDI values associated with each population were compared using the Siegel-Tukey test for homogeneity of spread.