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In pea (Pisum sativum L.) the af gene replaces leaflets with tendrils, and the tac gene restores small leaflets to the terminal portion of the tendrils of afaf plants. Normal (AfAf-TacTac), afila (afaf-TacTac), and afila-tendrilled acacia (afaf-tactac) near-isogenic lines in three genetic backgrounds were evaluated for 2 years in two locations to determine allocation of foliage area and weight of foliage components throughout the growing season. The percentage of total leaf area and weight due to stipule, tendril, leaflet, and tac leaflet were measured three times during the growing season in each environment. Highly significant foliage-type effects were detected for the percentage of leaf area and weight due to stipule and tendril at each sampling date. The pea leaf canopy exhibits large fluctuations in area and weight component allocation throughout the growing season. At 28 days after planting, stipules comprised 34%, 76%, and 53% of the total leaf area, and tendrils comprised 6%, 24%, and 13% of the total leaf area in normal, afila, and afila-tendrilled acacia types, respectively. At harvest, stipules composed 43%, 60%, and 53% of the total leaf area and tendrils composed 15%, 40%, and 22% of the total leaf area in normal, afila, and afila-tendrilled acacia types, respectively. Results from this study demonstrate that significant seasonal variation in allocations of foliage area and weight components exists among these three foliage types.
In the past 20 years, betalain pigments found in red beet (Beta vulgaris L.) have been adopted for use as natural red food coloring. In an effort to develop red beet populations with elevated levels of betalain pigment, recurrent half-sib family selection for high pigment and both high and low solids was practiced for seven cycles, resulting in the development of a high pigment–high solids (HPHS) and a high pigment–low solids (HPLS) population. Thirty-one randomly selected decamer primers were chosen to assess RAPD marker frequencies on genomic DNA samples isolated from 47 randomly chosen individual plants in each of cycles 1, 3, and 6 in both HPHS and HPLS. A total of 161 RAPD markers were evaluated. Chi-square and regression analyses were performed to determine presence/absence of linear trends in marker frequencies during the selection scheme. Comparisons were made for individual cycles between HPHS and HPLS and among cycles within HPHS and HPLS. Significant linear trends were detected in both cases for key RAPD primers. Chi-square tests revealed a subset of the markers which exhibited significant frequency changes across cycles were associated with selection as opposed to genetic drift. These data demonstrate changes in RAPD marker frequencies with recurrent selection and suggest linkage of RAPD markers to genes controlling pigment and solids in red beet.
Raw onion extract contains organosulfur compounds that prevent aggregation of platelets in human blood plasma and influence onion pungency. Organosulfur compounds are volatile and may change concentration during storage. A study was conducted to determine 1) whether antiplatelet activity of filtered onion extract decreases during time in cold (4C) storage; and 2) correlations among antiplatelet activity, pyruvic acid content, and percent solids during time in cold storage. Two low-pungency genotypes (8155 and Exhibition) and two high-pungency (W420 and W434) genotypes were grown in replicated plots in two Wisconsin and two Oregon locations in 1994. Bulbs were evaluated for antiplatelet activity, percent solids, and pyruvic acid content at 40-day intervals after onion harvest. Significant differences were found for pyruvic acid content, solids, and antiplatelet activity among dates of sampling, genotypes, and locations. Mean pyruvic acid concentrations ranged from 6.4 μm·ml–1 of extract for Exhibition, to 8.0 μm·ml–1 of extract for W420. Mean solids concentrations ranged from 5.8 g/100 g for Exhibition to 11.4 g/100 g for W434. Antiplatelet activity averaged over all genotypes increased over 120 days and was positively correlated with percent solids and pyruvic acid content.
Red beet contains betalain pigments recently adopted for use as natural food colorings. In an effort to develop beet populations with higher levels of betalain pigment, recurrent half-sib family selection for high pigment and both high and low solids was practiced in two populations for 7 cycles. PCR-based RAPD marker frequencies were assessed on genomic DNA samples isolated from 47 randomly-chosen individual plants from cycles 1, 3, and 6 in both populations. Number of PCR products per RAPD primer varied, with some yielding up to 5 scorable products. Chi-square and regression analyses were performed to determine presence/absence of linear trends in marker frequencies associated with selection. Significant linear trends in RAPD market frequencies were detected for certain primers both between populations and among cycles. These data demonstrate changes in RAPD marker frequencies with selection and suggest linkage of RAPD markers to genes controlling pigment and solids in red beet.
In the past twenty years, the presence of blood anticoagulants in plants has been confirmed by a range of clinical and in vitro investigations. The presence of anti-clotting factors in plants presents a unique opportunity for dietary enhancement of circularion and fibrinolysis. Experiments were conducted to assess variability in anticoagulant activity of a range of Allium wild species and cultivated accessions. Anticoagulant activity was determined via a platelet aggregation assay with human plasma. Extracts were prepared from 19 Allium species accessions and 24 cultivated accessions of Allium cepa, including standard inbred lines and open-pollinated popularions. Relative inhibition of platelet aggregation was measured for each accession and inhibition constants (IC50) were calculated. Data from this investigation dcmonstrate large IC50 variability among accessions. Larger IC50 differences (up to 45-fold) were measured among A. cepa accessions than among Allium species accessions (up to 16-fold). Yellow storagc-type A. cepa accessions exhibited the strongest inhibitory activity. Implications of these findings to onion breeding and platelet function will be presented.
Changes in endosperm type used for commercial sweet corn (Zea mays L.) production may affect corn protein levels. The two most widely used endosperm types are sugary-1 (su1) and shrunken-2 (sh2). To determine the effects of endosperm type on protein concentration, we calculated kernel N concentrations of dry mature kernels of seven inbreds near-isogenic for su1 and sh2 and of four samples of commercially canned su1 and sh2 sweet corn. Nitrogen values were converted to protein values using a standard conversion factor for maize. For the dry kernels and the canned samples, significant differences were detected between endosperm types for kernel protein concentration when measured on a weight basis. Averaged overall inbreds, the sh2 dry kernels had 30% more protein than su1 kernels. On a weight basis, the sh2 canned samples averaged 22% more protein than the su1 samples. When compared on a kernel basis, protein concentration of the two endosperm types did not differ. Thus, sh2 sweet corn marketed as a frozen or canned product may be identified as a higher protein product when the serving size is based on weight or calories.
Two mild and two pungent onion (Allium cepa L.) selections (hereafter referred to as cultitypes), W420B, W424B, MSU8155B, and Exhibition, were grown at two locations in two states (Wisconsin and Oregon) during 1994 and 1995. Onion bulbs were harvested, stored at 4 °C and sampled for antiplatelet activity, pungency, and soluble solids 10 days after harvest and every 40 days during a 210-day postharvest storage period. Significant cultitype × state and cultitype × year interactions were detected. However, these were primarily due to the change in rank of cultitypes within the mild or pungent group. Averaged over all environments, antiplatelet activity was significantly greater in 1994 compared to 1995 for all cultitypes. Significantly greater antiplatelet activity was measured for three out of four cultitypes grown in Oregon compared to Wisconsin. During postharvest storage, antiplatelet activity increased 61% and 56% across all cultitypes and across both states during 1994, and across all cultitypes in Wisconsin during 1995, respectively. Although pungency determination can be a good indicator for relative rankings of different cultitypes for antiplatelet activity, changes in pungency were not correlated with changes in antiplatelet activity during postharvest storage. Results demonstrate cultitype, environment, duration of postharvest storage and genotype × environment interactions influence pungency, soluble solids, and antiplatelet activity, which should be considered when assessing onion-induced antiplatelet activity.
Since the 1930s, more than 130 inbred lines and 60 hybrid cultivars of onion have been released in the public sector in the United States. Other than breeder's reports from the period 1946-1965 and anecdotal information kept by onion workers, no systematic treatment of the pedigree of public onion germplasm releases has been developed. The objective of this research was to collect, characterize, and display the genetic relationships among more than 200 public onion germplasm sources used in the United States since 1931. Pedigree information revealed that most modern onion cultivars in the United States descend from a few open-pollinated populations brought to this country by immigrants. For example, selection in the open-pollinated populations Common Yellow and Silverskin by onion farmers in the eastern U.S. resulted in the formation of Yellow Globe Danvers, which was a precursor to virtually all Eastern storage onion germplasm in the U.S. Open-pollinated populations such Yellow Globe Danvers, Valencia, Sweet Spanish, Bermuda, and Grano formed the foundation germplasm for the first public U.S. onion breeding programs. Findings from this study suggest a relatively narrow germplasm base of public onion germplasm in the United States; however, this narrow pool coexists alongside significant gains through scientific breeding efforts, particularly during the past 75 years.
Solid content is an important characteristic related to onion flavor, texture, and storability and has practical importance for the dehydration industry. Among the salutary effects of Allium vegetables on the cardiovascular system is the inhibition of platelet activity. Platelets play a key role in thrombosis and acute coronary syndromes because they facilitate blood coagulation. Pungency is also an important commercial trait. A 138-point genetic map is being used to identify and estimate the magnitude of quantitative trait loci controlling solid content, pungency, and health-enhancing attributes of onion. QTL controlling pungency, total solids, soluble solids, and antiplatelet activity were estimated using 54 F3 families, derived from the cross between Brigham `Yellow Globe 15-23' (BYG15-23) and `Ailsa Craig' (AC43). The families, the two parents, and controls were evaluated in four environments, at Palmyra or Randolph, Wis., during 1997 and 1998, on muck soils. For the analyzed traits there is evidence of trangressive segregation, the distributions are, in general, skewed towards the BYG 15-23 parent. Our results confirmed the existence of strong phenotypic correlations among the traits under study. QTL data available also suggest the existence of significant correlations between markers and the traits under study. Most of the markers that are significant for pungency and antiplatelet activity are also significant for solids, suggesting that these characteristics may be controlled by the same chromosome regions.
Aster yellows, an insect-vectored disease caused by a mycoplasmalike organism, limits vegetable crop production in the Midwestern U.S.A breeding effort was initiated in 1982 to develop aster yellows resistance in carrot. A synthetic population (AYSYN) composed of 5 open-pollinated varieties and 4 inbreds was assembled in 1982. Inbred lines and hybrids were extracted from AYSYN using a variety of methods. Selection in artificially-infected field sites was carried out from 1982 until 1989. Twenty-three inbreds and 3 hybrids were developed from AYSYN during the selection process. Replicated field experiments were conducted in 1990, 1991, and 1993 to determine the relative aster yellows resistance of these lines and hybrids in comparison with 6 check cultivars. Averaged over years, significant differences were detected for percent aster yellows infection among genotypes. Lines selected for resistance had a mean of 12% infected plant per plot as compared to 24% infection for standard cultivars. Results demonstrate the effectiveness of inbreeding and field selection for aster yellows resistance. This breeding effort represents the first report of aster yellows-resistant carrot germplasm.