The North American Pawpaw [Asimina triloba (L.) Dunal] shows great potential as a new fruit crop. Kentucky State University in Frankfort, Ky. is the site for the USDA National Clonal Germplasm Repository (NCGR) for Asimina species. Both the fruit and the trees themselves are of high value to growers and nursery producers. Pawpaw cultivars are currently propagated by grafting or budding onto seedling rootstock; no method currently exists to clonally propagate pawpaw on its own roots. Three methods of layering were attempted in this study to clonally propagate pawpaw: trench layering, pot layering, and mound layering. Both trench layering and pot layering experiments showed the importance of both juvenility and auxin application in adventitious rooting of pawpaw. Although rooting of more mature pawpaw shoots in these experiments did not exceed 30%, these propagation methods were more successful then previous attempts at rooting more mature pawpaw stems. Mound layering was less successful, but an easierto-root genotype of pawpaw in the KSU-USDA NCGR for Asimina spp. was discovered that may show promise for future propagation studies. Diversity in reproductive characteristics of pawpaw was also assessed in this study. Accessions in the KSU-USDA repository orchard collected from six different geographic regions were selected and trunk cross sectional area, total number of flowers, length of flowering, flowering peak, fruit set, total number of clusters, total number of fruit, number of fruit per cluster, average fruit weight, yield by weight, yield efficiency, length of harvest, harvest peak, and growing degree days required for ripening were evaluated. Significant differences were found among the regions in most of the characteristics evaluated. Correlations were also found between several vegetative and reproductive characteristics. This indicates that a significant level of reproductive diversity exists within KSUs repository collection, and between pawpaws collected from different regions of the native range.

No description available.

Genetic consistency within varieties is essential to quality assurance for any agricultural product. While the Australian coffee industry targets high quality coffee, there is observed morphological variation within coffee varieties in New South Wales plantations. This variability may result from environmental, genetic and/or management factors. Genetic factors can be tested by molecular markers which can also shed light on the questions concerning crop quality management. A review of the literature showed low genetic variation in C. arabica. Hence four different molecular marker systems were used in this study to detect possible genetic variation within and between varieties of local coffee grown in Northern New South Wales (NNSW), Australia. Genetic variation in eighty-four seed propagated coffee (C. arabica) accessions, mainly from two commercial varieties (K7 and CRB) in NNSW, were tested using various PCR-based marker systems (RAPDs, ISSRs, SSRs and AFLPs). Eleven accessions from Central Highland, Vietnam, were used as reference material. While RAPD and ISSR did not distinguish intra-varietal molecular variation, SSR and AFLP data revealed the degree of genetic variability and the relationship among individuals within and between coffee varieties. Despite observed morphological variation within supposedly single variety plantations in NNSW, the genetic variation, measured by genetic distance, revealed in this study was very low (K7: 0.193; CRB: 0.205). There exists genetic variation between different farms sharing the same cultivar (K7) which suggests differences in the management of plantation establishment and sourcing of trees. The genetic variability is not aligned with off-type individuals observed in K7, but is with off-type CRB plants which is probably due to inter-varietal hybrids from unintentional outcrossing. The mean level of genetic identity between cultivars derived from the two distinct types of C. arabica is moderate (0.641). Although genetic variation within and among arabica cultivars is low, sufficient DNA polymorphism was found among some C. arabica accessions to allow differentiation. The results in this study suggested that even the elite cultivars, which have been exposed to intensive selection, still show a certain degree of genetic variation amongst individuals within each cultivar even though C. arabica is a predominantly selfing species and has a narrow genetic foundation. The congruence between AFLP and SSR data sets suggests that either method individually, or a combination, is applicable to genetic studies of coffee. SSR alone clearly distinguished and revealed inter-varietal heterogeneity but were more powerful when combined with AFLP.

The agronomical evaluation and the comparative work of six multiannual forage species was conducted in the facilities of the Benson Institute, in the community of Contorno de Letanias, Ingavi province, La Paz. The objectives were to evaluate the agronomic behavior, as well as to evaluate the dry matter (DM) yield of six multiannual forage species (grasses) under local conditions, and to determine the partial cost of production of the studied species. The annual mean temperature was 9.14°C, and 517.6 mm of precipitation. The test was conducted under the random block design test, with six different forage species, and three repetitions. The evaluated species were: Hybrid grass (Agropyrum crisantum x A. desertorum), Bromus grass(Bromus inermis), Phleum grass (Phleum pratense), Pubescent grass (Agropyron trichophorum), Orchard grass (Dactylis glomerata), and Weeping lovegrass (Eragrostis curvula). The evaluated response variables were: Plant density (%), plant height (cm), base area (m²), tip area (m²), leaf/stem relationship, dry matter yield (kg/ha), and plant vigor. The forage species (grass) that presented a better behavior in relationship to plant density were the weeping lovegrass, Phleum, Orchard, Bromus, and Pubescent grass with: 92.17, 84.44, 75.95, 70.77, and 68.6%. The hybrid grass presented the least density with a 55.50% respectively. According to plant height at two different cut times, the Orchard, Pubescent, Weeping lovegrass, Bromus, Phleum, and Hybrid grass species presented a mean height of 23.0, 26.24, 15.31, 12.27, and 15.5 cm respectively, a tip area of.037, 0.26,.032, 0.32, 0.28, and 0.25 m², and a base area of 0.14, 0.09, 0.10, 0.16, and 0.10 m². The dry matter yield (The total sum of two cuts) was of 3936.0 kg/ha for Pubescent grass, 3459.0 kg/ha of Bromus grass, 2780.7 kg/ha of Weeping lovegrass, 2358.0 kg/ha of Hybrid grass, and 2089.0 kg/ha of Pleum grass. The relationship leaf/stem relationship resented an average of 1.13, 3.38, 3.71, 2.84, 2.49, and 2.93 respectively. The species: Orchard and pubescent grass presented a variable cost of 1384.9 and 1604.9 Bs/Ha in relationship to the other studied species. Also, both grasses (bromus and pubescent) presented a marginal return of 138%; therefore, Orchard grass (Dactylis glomerata) is recommended as an alternative species.

Failure of viable seed to germinate results in poor stands and often in lower yields. Some of the more important factors that affect germination of seed are temperature, moisture, aeration, and alkalinity.

Part 1. Formation and control of chlorophyll, solanine alkaloids, and sprouts of potato (Solanum tuberosum L.) tubers Incorporation of radioactive carbon from acetic acid-2-14C (sodium salt), β-hydroxy-β-methylglutaric acid (HMG)-3-14C, L-leucine-U-14C, L-alanine-U14C, and D-glucose-U-14C into the predominant glycosidic steroidal alkaloids, &alpha-chaconine of potato sprouts was 4.88, 9.0, 15, 24, and 20 times less than that of mevalonic acid (MVA=2-14C (DBED salt), respectively. The efficiency ratio revealed that β-hydroxy-β-methylglutaric acid (HMG)-3-14 was incorporated via acetate or acetoacetate. The distribution of radioactivity originated from D-glucose-U-14C was nearly nine times higher in the glycoside moiety than that in the aglycone part of the glycoalkaloids. Apparently, Alar( succinic acid 2,2-dimethylhydrazide), Ethrel or Ethephon (2-chloroethylphosphonic acid), and Telone (1 ,3-dichloropropene and related chlorinated hydrocarbons) significantly reduced the rate of incorporation of β-hydroxy-β-methylglutaric acid (HMG)-3-14C into the alkaloids. A catalytic conversion of solanidine and UDP-glucose-U-14C to β-glucoside by the enzymatic system in a suspension of potato slices and the enzyme preparation from sprouts demonstrated the presence of β-glucosyltransferase in Solanum tuberosum L. Stepwise synthesis of α-solanine and α-chaconine from solanidine in potato tubers or sprouts seems possible. Formation of solanine alkaloids in peeled potato slices was stimulated when stored at 15 and 24 C in dark or light (200 foot-candles). The slices held under light developed nearly three to four times more alkaloids than those held in the dark. Significantly higher concentrations of solanine alkaloids were formed in the late stage (after 24 hours) than in the early stage of the storage period . Hence, it can be concluded that when potatoes are sliced for chips or French fries, they should be processed immediately, before the glycoalkaloids are synthesized in higher concentrations. Post-harvest application of chemicals, such as Phosfon (tributyl 2,4-dichlorobenzylphosphonium chloride), Phosfon-S (tributyl 2,4-dichlorobenzylammonium chloride), Amchem 72-A42 [2-(p-chlorophenylthio)- triethylamine], Amchem 70-334 or CPTA [2-(p-chlorophenylthio)-triethylamine hydrochloride], Nemagon (1,2-dibromo-3-chloropropane), and Telone (1,3-dichloropropene and related chlorinated hydrocarbons) at the concentrations of 250, 500, and 100 parts per million (ppm) in water; glycerin (10, 20, and 30 percent weight by volume [w/v] in water); and mineral oil (1.25, 2. 5, 5, 10, 15, 20, and 100 percent [w/v] in ether or petroleum ether) significantly inhibited the formation of chlorophyll and solanine alkaloids in the peripheral (periderm and outer parenchyma) zone of potato tubers exposed to a fluorescent light (200 foot-candles) for 6 or 7 days at 16 C and 60 percent relative humidity. The rates of inhibition increased with concentration of chemicals studied. A 10 percent solution of mineral oil was the minimum required concentration for effective control of chlorophyll and solanine alkaloids. The tubers dipped in 10 percent mineral did not develop chlorophyll on exposure to light (200 foot-candles) for 4 weeks, while the overall rate of inhibition of alkaloids was significantly high. In general, oil treatments were the most effective in controlling the formation of chlorophyll, solanine alkaloids, and sprout growth. Part II . Formation and control of carbonyl compounds of tomato (Lycopersicon esculentum Mill.) fruits Incubation of unsaturated fatty acids such as linoleic and linolenic acids with the crude soluble extract from tomato fruits produced carbonyl compounds. The enzyme preparations did not catalyze the conversion of saturated or monounsaturated fatty acids to carbonyls. Inability of potassium cyanide to inactivate the crude soluble extract proved that degradation of these fatty acids was mediated by lipoxidase and nonenzymatic oxidation by heme compounds was eliminated. These findings were supported by the fact that hydrogen peroxide, an inhibitor of lipoxidase enzyme, had inhibitory effects on the degradation of linoleic and linolenic acids by the tomato extract. Hexanal was found to be one of the products of the enzyme reaction. The identity of hexanal was confirmed by comparing the physical properties such as retention time, infra-red and ultra-violet absorption bands, and Rf value with those of an authentic sample . Biogenesis of hexanal from linoleic or linolenic acid was further substantiated by the use of uniformly labeled 14C isotopes of these fatty acids with the crude soluble extract, filtered homogenate, and tissue slices. Maximum activities (as evidenced by the production of carbonyls) were observed in the extract prepared with and incubated in a buffer medium of pH 7.5 (0.l M, Tris-HCl). The degradation of linoleic and linolenic acids was maximum at 30 C when incubated for 4 hours with 1 ml of the crude soluble extract. The enzymatic activity was enhanced by metal ions and compounds containing free -SH groups. Increase in the production of carbonyls by addition of citric and L-ascorbic acid may result from their metabolism. In general, ripe fruits contained greater enzymatic activities but smaller amounts of linoleic and linolenic acids than green fruits . The activity of the crude extract was increased by dialysis and the ammonium sulfate fractionation between 30 and 70 percent saturation. The rates of degradation of linoleic and linolenic acids catalyzed by the insoluble fractions of tomato extracts were more than those by the corresponding soluble fractions. Tomato fruits (green-wrap or large green) stored under hypobaric or sub-atmospheric pressures were analyzed for their volatiles after ripening. The concentrations of selected carbonyls (acetaldehyde, 2-methyl propanal, butanal, 3-methyl butanal, and hexanal) and some other volatiles decreased substantially with decrease in storage pressure.

Trichloroethylene (TCE) was widely used as an industrial solvent and degreasing agent for most of the twentieth century. It is now a widespread groundwater contaminant. Phytoremediation may be a cost-effective cleanup method for TCEii contaminated soils and groundwater. Studies of environmental TCE fate are complicated by its volatility. The literature repons both significant and insignificant plant uptake of TCE. Conflicting findings may be due to differences in exposure level, conditions, and duration of the studies, or to experimental artifacts from laboratory systems. This research quantified plant uptake and volatilization of TCE using a unique laboratory system. Hybrid poplar trees were exposed to 1 or 10 ppm TCE over a 43-d period. [14C]TCE was added to four high-flow, aerated, hydroponic plant growth chamber systems designed to provide high mass recoveries, an optimal plant environment and complete separation between foliar and root uptake. Transpiration stream concentration factors (TSCFs) for TCE, calculated from total [14C]TCE in shoot tissues plus phytovolatilized 14C, were 0.11 for two 1 ppm treatments and 0.15 for a 10 ppm treatment with roughly 25% attributed to phytovolatilization. Though extending study duration from 26 to 43 d resulted in accumulation of more mass of 14C in plant tissues, it had no effect on TSCF. These TSCF values are much lower than other published experimental values and values predicted by a theoretical relationship between TSCF and octanol-water partition coefficient. The TCE metabolites trichloroethanol (TCEt), trichloroacetic acid (TCAA), and dichloroacetic acid (DCAA)were identified in plant tissues of the 10-mg/L treatment. Hybrid poplar uptake ofTCAA and TCEt was quantified using a simpler aerated hydroponic system. TSCF values were calculated based on extractable parent compound in shoot tiss ues. TSCF for TCEt was < 0.01. Presence of TCAA in hydroponic solution and in leaf and root tissues indicated transformation of TCEt to TCAA. TSCF for TCAA was < 0.03 and decreased with increasing exposure concentration. TSCF also decreased under oxygen-limited root-zone conditions. Presence of DCAA in leaf and root tissues indicated transformation ofTCAA to DCAA. Transformation of parent compound, coupled with low extractability, may contribute to low TSCFs.

Dodder (Cuscuta spp.) is a parasitic weed which attacks alfalfa, clovers, lespedeza and many other species of plants. This pest is especially troublesome when these crops are grown to produce seed.

Although the parent of the present sugar beet was probably known and used before the building of the pyramid of Cheops (22), it was as recent as 210 years ago that Marggraf obtained the first crystalized sucrose from the root. It was 40 years later before Achard claimed its potentialities as an efficient industry. The product rapidly passed from the status of a luxury to a vital necessity, until today sugar beet production receives some protection or preference in every country where sugar beets are grown. Throughout its 174-year history it has probably been beset with a greater variety of problem and more failures than any other industry before or since. One of the greatest problems has been the actual means of sucrose extraction and determination. The determination of sucrose in sugar beets is the most important function in a beet sugar factory laboratory (3). This value is necessary as the basis for calculations of sugar yields and losses, for fixing the value of beets in factories where these are bought on the basis of their sugar content and for other purposes. Sugar content determinations are also for vital importance to the plant breeder, soil scientist, plant physiologist, and other researchers concerned with sugar beet analysis. Values of such importance should be determined by methods of corresponding accuracy. However, in 1927 Stanek and Vondrak (3) stated that there is no routine method as yet which permits the determination of the sugar in the beet to within an accuracy of 0.1 per cent. It is doubtful that the fundamental accuracy of the saccharimetry methods has improved much since this time. Numerous methods of sucrose analysis are used and are being recommended for use both in sugar beet factory and research laboratories. Although most methods now used are based on the principle of aqueous digestion and single polarimetry, there are wide variations in actual procedures. The available literature is deficient in adequate comparative studies into this problem. It would be of considerable value to researchers in sugar beet production and analysis to know the relative accuracy and precision of these methods and the effects of the several variables now prevalent.

Since the early Eighteenth Century the significance of nectar secretion has been debated. Some have reasoned that it is reabsorbed into the plant and used as energy for the developing embryo while others believe it is a waste product which attracts pollinating insects. It has been suggested (Brink and Cooper, 1947) that the nutrient supply to developing ovules is a major factor in the development of seed. Also, alfalfa fields pollinated by pollen-collecting bees produce greater seed yields than those pollinated by nectar collectors (Bohart, Nye, and Levin, 1955). It is a well-known fact that more flowers are tripped by the pollen collectors, but it is debatable whether the nectar not taken by the pollinators has any influence on the quality or amount of seed set. It is then necessary to find whether the nectar not taken by bees is used by the plant before studies can be made to show its effect on seed and forage yields. The object of this study was to treat flowers of several families with C14 labeled sucrose and determine by the use of autoradiograms if sugars can be absorbed by nectaries, where the sugars are translocated, and when absorption takes place.