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- Author or Editor: D. N. Maynard x
Yield and quality of seedand vegetatively propagated rhubarb (Rheum rhabarbarum L.) for annual production were evaluated for four seasons. Selection of `Victoria' seedlings based on petiole color was not effective in increasing the proportion of red mature petioles. Yields from seed-propagated annual rhubarb were always higher than yields from single-bud crown divisions and from crown divisions in 1 of 2 years. Petiole color of vegetatively propagated rhubarb was always superior to that of seed-propagated rhubarb. GA applications increased early yield from single-bud divisions, but reduced petiole weight of early and total harvest of `McDonald' rhubarb. Chemical name used: gibberellic acid (GA).
Yield and quality of seed- and vegetatively-propagated rhubarb [Rheum rhabarbarum L.) for annual production were evaluated for 4 seasons. Field planting of transplants or crown divisions in late October or early November resulted in harvests beginning in early to late January and continuing until late April. Selection of `Victoria' seedlings based on petiole color was not effective in increasing the proportion of red mature petioles. Yields from seed-propagated annual `Victoria' rhubarb were always higher than yields from `McDonald' single-bud crown divisions and higher than yields from `McDonald' crown-divisions in one of two years. The four-year average yield for `Victoria' seed-propagated rhubarb was 20.4 Mg·ha-1 whereas `McDonald' crown-division-propagated rhubarb had a two-year average yield of 15.8 Mg·ha-1. On the other hand, petiole color of vegetatively-propagated rhubarb was always superior to that of seed-propagated rhubarb. GA applications increased early yield from `McDonald' single-bud divisions, but reduced early and total harvest petiole weight.
No records exist of the first instance of crop fertilization by Neolithic man. For that matter, most of the repeated events leading to horticultural practice in the first 250 years following colonization of the U.S. remain unrecorded. Of course one such incident, the lessons of Squanto in corn fertilization, is familiar to all.
Fruit set of 'Crimson Sweet', 'Jubilee II', 'King of Hearts', 'Mickylee', and 'Sangria' watermelons was studied in Florida, In 1991 and 1992 seasons at Bradenton and Leesburg, In 1991, fruit set at Bradenton occurred primarily from 7-10 October. At Leesburg, fruit set in at least one of the four varieties occurred over 19 days. However, there were flushes of fruit setting 25-28 September and again 5-7 October. Fruit set over the entire season ranged from 11 to 16% at Leesburg and between 17 and 20% at Bradenton. In 1992, fruit set occurred primarily between 11 and 17 October at both locations. Fruit set for the entire season ranged from 16 to 21% at Bradenton and 22 to 31% at Leesburg. The effects of bee attractants on watermelon fruit yield were studied in Manatee (Bradenton) County in fall 1991 (Bee Scent) and in Manatee and Lake (Leesburg) counties in spring 1992 (Bee-Here). Bee attractants did not significantly affect yield in three of four experiments. In the fourth experiment, early yield and average fruit weight for the entire season were increased significantly following application of the bee attractant.
Watermelon, Citrullus lanatus (Thunb.) Matsum. & Nakai, requires insects, most commonly honey bees, for pollination and fruit set. The transfer of an adequate amount of pollen is essential to ensure optimum fruit set, size, and shape. To encourage bee visits and the transfer of pollen, two applications of Bee-Scent*, a bee attractant, at 2.47 liter·ha-1 were made to watermelon on five farms in central and southwest Florida. Honey bee, Apis melifera L., activity was monitored for two days following each application and yield and fruit quality were determined. On only a few occasions was increased honey bee activity noted. Application of bee attractant increased total yield in one field in central Florida and resulted in an increase in early yield at all three locations in southwest Florida. Soluble solids content of mature fruit was not directly affected by treatment. Treatment increased the seed content of fruit from three of five farms.
Mature seeds occur occasionally in triploid watermelon fruit. In one trial, the average number varied from 0.3 to 28.7 seeds per fruit in 30 entries and from 0.5 to 8.6 seeds per fruit in the cultivars within this group. The frequency of mature seed in triploid fruit with the same tetraploid parent ranged from 0.3 to 3.0 and from 1.25 to 5.0 seeds per fruit in triploid fruit having the same diploid parent. Tetra A, with 151 seeds per fruit, produced triploids with 6 seeds per fruit; whereas Tetra B, with 74 seeds per fruit produced triploids with only 1.3 seeds per fruit. Date-of-flowering of diploid watermelon cultivars used as pollenizers for triploids affected maturity date of the triploids. Icebox-types that flower early produced higher early yields of triploid fruit; whereas standard cultivars that flower later produced higher yields late in the season.
Considerable concern for the quality of our environment and its effects on various species of plant and animal life, and of course humans, has been recently expressed. One specific aspect of this concern is the possibility that vegetable products may contain large amounts of nitrate. The implication made is that increased use of nitrogenous fertilizers must always result in an increased nitrate concn in the plant product (4). This is not necessarily the case, since a great number of factors govern nitrate accumulation in plants.
Leaves of field-grown cauliflower (Brassica oleracea L. Botrytis group) plants with tip-burn had lower Ca concentrations than normal leaves but did not differ in N, P, K, or Mg concentrations. In greenhouse experiments plant growth and leaf Ca increased, whereas the severity of tipburn decreased with increased Ca supply. ‘Imperial 10–6’ cauliflower leaves had a higher Ca concentration and were more tolerant of tipburn than ‘Self Blanche’ cauliflower.
Fall applications of K and
Peroxidase activity measured on leaf disks of vegetable plants is suggested as a rapid tissue test for diagnosing iron deficiency. The reaction is rapid, may be executed under field conditions and apparently corresponds with the metabolically active part of the iron in the leaf tissue.