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- Author or Editor: Dyremple Marsh x
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A wide range of methodologies, ranging from Leonard jar to growth pouch have been used to investigate the nitrogen fixation process in leguminous crops. The effectiveness of most of these research methods have been questioned. Problems encountered vary from difficulty in root separation to water log conditions. This study was undertaken to determine the effect of different growing media on nodule development and harvestability. Black and Red seed coat kidney bean were surface sterilized and inoculated with the Rhizobium phaseoli strain UMR 1899. Seeds were planted in 8.5 cm diameter sterile clay pots containing the respective growing medium. These growing media were sand, Promix GM, Promix BX, and fritted clay. The black seed coat kidney bean had higher germination rate under all media for all dates recorded. Black kidney bean grown in sand and fritted clay had plant heights significantly greater than ones grown in the other media on the third harvest date. Nodule activities as measured by shoot dry weight and nodule number were significantly higher in both beans grown in fritted clay than in other media. Promix GM plants with dry weight of .45g for the black bean and .32g for the red beans were the lowest. Nodule separation from the growing media was easiest when plants were grown in sand, however, this was not significantly different from that of plants grown in fritted clay.
Abstract
The number of people of Caribbean, African, and Asian descent living in the United States is quite high. Most of these people live in diverse ethnic centers, such as New York, San Francisco, Chicago, Miami, and Atlanta. It might be profitable to provide traditional foods (2, 3) for these groups. Many of these foods already are imported into the United States. However, importation sometimes is not possible because of (a) inadequate storage facilities, (b) low cost effectiveness, and (c) small amounts that need to be imported (J.R. Suah, CARDI, personal communication). Three of these crops that may be grown in Missouri are hot pepper, ‘Scotch Bonnet,’ a low moisture pumpkin, ‘Calabash,’ and yam. ‘Scotch Bonnet,’ pepper grown under tropical conditions is semiperennial with peak production occurring in the first year. ‘Calabash’ pumpkin, requires a growing season of at least 7 months. Yam requires a 6- to 10-month growing period under tropical conditions. The potential production of these vegetables in the United States has not been adequately investigated. We, therefore, investigated their performance under mid-Missouri growing conditions.
Pigeonpea [Cajanus cajan (L.) Millsp.] and cowpea [Vigna unguiculata (L.) Walp.] seeds were inoculated with broth cultures of Rhizobium strains 3278, 3458, and 3472 at a population of ≈9.5 × 10 g viable cells/ml. They were planted at three air temperature regimes: 20/10C, 30/20C, and 38/25C (day/night), which generated variable rhizosphere temperatures of 17/6C, 26/15C, and 33/20C, respectively. Seeds and/or seedling roots were sampled at 3, 7, 11, and 15 days after planting and Rhizobium survival was enumerated as viable cells on agar media. Only strain 3458 in association with pigeonpea genotype ICPL8304 had a higher population at day 15 than that at the earlier sample dates. The duration of the strains in the rhizosphere, rather than temperature, influenced population changes. No strain showed a consistent increase in cell numbers from inoculation to 15 days after planting. There was no clear pattern of population changes for any strain within or across temperatures, hence it was difficult to identify any strain as having superior growth habits over another.
The influence of benzyladenine (BA) and ethrel on vegetative and reproductive characteristics of 2 pigeonpea genotypes was evaluated in field and greenhouse study. Plants sprayed with benzyladenine or ethrel at 400 or 800 ppm levels at both the vegetative and flowering stages tended to be smaller, had more floral abscissions and produced more pods than those sprayed only at the flowering stage. Increased chemical concentration decreased plant size. Plants treated with BA produced several curved distorted leaflets. None of the applications in the field study significantly improved pod set over the 23% recorded for the controls.
Low temperatures adversely affect legume- Rhizobium symbiosis in the temperate regions. Plant growth and N-fixation of two pigeonpea and two cowpea genotypes were examined at three temperature regimes (20/10 C, 30120 C and 38/25 C day/night). Sterilized seeds were inoculated with broth culture containing approximately 1 × 109 cells ml-1 of Bradyrhizobium USDA 3278, 3458 and 3472. Nitrogen fixation by pigeonpea was inhibited at 20/10 C. Cowpea IT82E-16 inoculated with USDA 3458 at 20/10 C produced the greatest amount of nodules. Inoculation had no effect on Nitrogenase activity in pigeonpea. Pinkeye Purple Hull inoculated with USDA 3472 at 20110 C had the highest Nitrogenase activity. These results indicate a wide degree of variability among genotypes and Bradyrhizobium in their response to temperature.
The number of viable cells produced by Rhizobium on solid media gives an indication of the strains survivability when used as an inoculant. This study was conducted to determine the viability of different strains of Bradyrhizobium. and their ability to nodulate pigeonpea (Calanus calan) and cowpea (Vlgna unguiculata) genotypes at two temperature regimes: 20/10°C and 30/20°C (day/night). Bradyrhizobium strains USDA 3278, 3362 and 3458 were cultured in yeast mannitol broth for 7 days from which a 10% dilution was made. From this dilution, 0.1 ml of a further 10 dilution was allowed to grow on yeast mannitol agar plates at the test temperatures. Strains cultured at 30/20°C had a higher number of viable cells than those cultured at 20/10°C for 4 days. While there was no difference between Rhizobium strains 3278 and 3362, strain 3458 had the highest number of cells per ml of 7-day old broth culture. Pigeonpea and cowpea plants inoculated at 20/10°C with the three Rhizobium strains and those inoculated with 3362 at 30/20°C had no nodules at 30 days after planting. At 30/20°C, plgeonpea and cowpea plants Inoculated with strain 3458 produced a higher number of nodules than those inoculated with strain 3278. These results indicate that temperature Influences the Rhizobium strains and their ability to nodulate plgeonpea and cowpea.
There is an increasing number of tropical legumes presently grown under temperate conditions with varying amounts of success, This growth chamber study examines the germination, modulation and N2 fixation of two cowpea and one pigeonpea genotypes at two temperature regimes, 15/10° C and 20/10° C, day/night. Prior to planting, surface sterilized seeds were inoculated by soaking in yeast mannitol broth containing approximately 2 × 106 cells ml-1 Bradyrhizobium (USDA 3384). Uninoculated control seeds were soaked in sterile water before planting. Air temperature of 15/10°C, day/night delayed seed germination, nodule initiation, and seedling development. Inoculated cowpea seeds planted at the 20/10° C regime attained 50% germination within 9 days, while inoculated pigeonpea took 13 days under similar regime. Bradyrhizobium persistence was not significantly affected by low temperature. The results indicate that nodule development for both crops were inhibited chiefly by a lack of developing root hairs at low soil temperature,
Efforts to produce specialty crops by Missouri farmers have been met with varying success. This success is reduced by the lack of established cultural practices necessary for the economic production of these crops. Ten kiwano plant introductions obtained from the Central Regional Plant Introduction Station in Ames, Iowa, were planted in the greenhouse. Seedling vigor was determined by shoot length, shoot dry weight, and number of leaves produced. Uniform seedlings from each accession were transplanted in the field with within row spacings of 0.9 m and 1.3 m. Seedling vigor varied significantly between accessions. Yields of field grown kiwano were affected by plant spacing, with the closer spaced plants having the higher yields. Plant spacing had no effect on fruit color, fruit length, or fruit width. Incidents of fusarium wilt were prevalent at both plant spacings.
A greenhouse experiment was conducted to examine the relationship between tissue B concentration and dry matter accumulation in broccoli. `Pirate ' was grown in fine silica sand and supplied nutrient solutions containing 0.2, 0.8, 1.4, 2.0, 2.6, 3.2, 3.8, and 4.4 mg·liter-1 B. Plants were sampled for the 5th, 10th, and 15th fully expanded mature leaf, and plant material was collected' for dry matter measurement and boron analysis at each growth stage. The lowest specific leaf weights for the 5th, 10th, and 15th leaves were obtained with the 4.4 mg·liter-1 treatment. At maturity, leaf, petiole stalk, and shoot dry weights were lowest at 4.4 mg·liter-1 B. Treatments supplying less than 3.2 mg· liter-1 B, resulted in a notable decrease in tissue B concentrations from the 5th to the 15th leaf. There was a linear increase' in B concentration in all leaf tissue samples as B treatment increased. At maturity, optimum B concentrations of 531.5, 73.7, 29.8, and 64.6 mg·g-1 were found for the lamina, petiole, stalk, and head, respectively. These concentrations occurred in plants receiving treatment levels of 2.0-3.8 mg·liter-1 B.