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The growth processes of most horticultural crops are too slow to be visually interesting to students. Time lapse photography has been used for years to speed up the action and make plants “come alive.” With the advent of video technology, time lapse techniques have become convenient, easy, and affordable. The system which we have found satisfactory consists of a time lapse video cassette recorder, linked by optical fiber cable to a closed circuit color video camera in a ventilated housing. Typically, the camera has been set up in a greenhouse compartment, monitoring growth processes of vegetable crops, and linked by cable to the VCR in an office 80 m away. Equipment costs with one camera are less than $3000. Two cameras can be set up to do comparative growth studies, with two images side-by-side, using a screen splitter. Costs of the latter system is about $4500. Growth processes such as cabbage head formation, curd growth in cauliflower, and weed-crop competition of mustard and peas have been the subjects so far. The technique lends itself to increasing the visual impact of teaching, and gaining a better understanding of plant growth processes in research.
Eight plant bed fertilizer treatments (N–P–K) were evaluated for the effect on plant production and sweetpotato yield. The treatments ranged from 0–0–0 to 450–450–450 lb/ac. `Beauregard' roots were bedded. After the first plant cutting, 50 lb/ac 34–0–0 was applied to half of the beds. For the second cutting, the 0N–0P–0K treatment without additional N produced plants with less green weight compared to the other treatments; there were no differences between the other 15 treatments. For the first plant cutting, 150–150–150 and 150–300–450 lb/ac produced plants with less green weight compared to 0–0–0, 75–150–300, 300–450–600, and 450–450–450 lb/ac. There were no differences in sweetpotato yield due to plant bed fertilization.
Greenhouse rose (Rosa × spp. L.) production is facing the use of poor-quality irrigation waters and regulatory pressures to recycle runoff and drainage effluents. Two experiments (were conducted to evaluate the yield and quality and ion accumulation responses of roses grafted on various rootstocks to increasing salinity stress. In Expt. 1, the scion ‘Bridal White’ grafted on ‘Manetti’, R. odorata (Andr.), ‘Natal Briar’, and ‘Dr. Huey’ were irrigated over four flowering cycles with complete nutrient solutions supplemented with NaCl at 0, 5, and 30 mm. In Expt. 2, plants of ‘Red France’ on ‘Manetti’ and ‘Natal Briar’ were irrigated over six flowering cycles with complete nutrient solutions supplemented with NaCl + CaCl2 (2:1 m ratio) at 0, 1.5, 3, 6, 12, and 24 mm. Salt concentration increases significantly and negatively affected the biomass, cut flower production, and foliage quality of the roses in both experiments, but the responses were modulated by rootstock selection. ‘Manetti’ plants in general sustained better absolute and relative biomass and flower yields, accumulated less Na+ and Cl− in its tissues, and showed less toxicity symptoms with increasing salinity than the others. ‘Natal Briar’ also had similar absolute productivity responses as ‘Manetti’ but were afflicted by a significantly different mineral nutrient profile, including higher accumulations and toxicities with Na+ and Cl− that led to lower foliage visual ratings. Conversely, the relative yields of plants on ‘Dr. Huey’ and R. odorata were similarly reduced by increasing salinity, but the former had lower Na+ and Cl− concentrations in its tissues and better visual scores than the latter, which fared as the worst. A combined analysis of the results suggests that on a productivity basis (biomass and flower yields), greenhouse roses could withstand overall maximum electrical conductivities (i.e., osmotic effects) of applied fertigation solutions of 3.0 ± 0.5 dS·m−1. On the other hand, and considering the aesthetic responses (visual scores) of on-plant and harvested foliage (cut flower shoots), greenhouse rose tolerance to applied Na+ and Cl− concentrations (ion-specific effects) could range up to 10 ± 2 mm.
One hundred sixteen rose (Rosa spp.) cultivars were evaluated under minimal input conditions in north-central Texas for 3 years. Plant quality data included overall plant performance, number of flowers, percentage of bloom coverage, final vigor, and survival. Disease ratings for black spot (Diplocarpon rosae), petal blight (Alternaria alternata), powdery mildew (Sphaerotheca pannosa), and aphid (Myzus spp.) infestations were previously reported. Of the original 116 cultivars, 25 had 50% or higher mortality during the trial. Own-root cultivars performed significantly better than the grafted cultivars and had significantly better survival (P = 0.001). As a class, the Polyantha cultivars exhibited the best overall performance, mean bloom percentage, final vigor and survival, while cultivars in the Hybrid Tea class had the worst performance in all measures. Foliar nutrient content, bloom number, and mean percentage of bloom were not good predictors of overall performance. Of the diseases monitored, black spot was the most severe and was closely correlated to overall performance and final vigor, but was not the only factor determining overall performance. The top five cultivars in mean overall performance were RADrazz (Knock Out™), Caldwell Pink, Sea Foam, Perle d'Or, and The Fairy, in descending order.
To enlarge the palette of environmentally-responsible landscape plants, 117 garden rose cultivars were evaluated under minimal input conditions. Other than mulching and irrigation, no other inputs were provided, including no fertilization and no pesticide applications. Plants were established in completely randomized blocks with four reps in the spring of 1998 with data collection beginning in 2000 and continued through 2002. Data on overall performance (an index comprised of flower number, percent of plant covered with flowers and plant growth) and relative chlorophyll content were collected the first and third week of each month from April through October. Disease ratings or incidence ratings were collected for Diplocarpon rosae Wolf (black spot), Alternaria sp. (petal blight) and Sphaerotheca pannosa (powdery mildew). Statistical analysis was performed on the mean data for all dates. `Knockout' was the top rose for overall quality with little or no disease observed, high foliage quality, and continuous flowers from spring until late in the fall. `Knockout' also ranked among the top rose cultivars in terms of overall nutrient concentrations (N, P, K, and Fe) in new growth tissue. Most of the hybrid tea roses such as `Peace' and `Double Delight' died in at least three blocks due to disease and a lack of vigor.
`Beauregard' storage roots which were discarded from the Mississippi sweetpotato foundation seed program because of the presence of flesh mutations were bedded in Spring 1991. After the plants were pulled from the roots, the roots were further examined, and the flesh mutations were characterized by size and frequency. The progency from the original roots were examined for flesh mutations for three generations in 1991, 1992, and 1993. The degree of mutation in the original root did not influence the degree of mutation in succeeding generations of storage roots. In 1992 and 1993, the degree of mutation in the third and fourth generation roots did not differ from that of storage roots grown from plants from the foundation seed plant beds.
`Beauregard' and `Centennial' were planted in plots of four different topsoil thicknesses (0, 3, 6, and 9 inches) to evaluate the effect of topsoil thickness on sweetpotato production. In 1994, the 0-inch topsoil treatment produced a greater total marketable yield for `Beauregard' than did the 6- and 9-inch topsoil for `Centennial'. The 0- and 9-inch topsoil produced a greater total marketable yield than did the 3- and 6-inch treatment. When averaged over 2 years, 1993 and 1994, there were no differences in total marketable yield in either `Beauregard' or `Centennial' due to topsoil thickness. Averaged over both years, topsoil thickness had no effect on weight, diameter, or length of `Beauregard' roots.