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- Author or Editor: R. Crofton Sloan x
The sweetpotato foundation seed program in Mississippi is committed to producing and supplying high-quality sweetpotato seed to the Mississippi sweetpotato industry. In 1991, a study was initiated to evaluate the effects of small heteroclinal chimeras in foundation seed roots on the root flesh quality in subsequent generations. The presence of small heteroclinal chimeras in parent seed roots did not increase the number or size of chimeras in three subsequent generations of storage roots.
Thirteen single-stem and 16 branching sunflower (Helianthus annuus) cultivars were evaluated in field trials at the North Mississippi Research and Extension Center in Verona for cut flower production. The objective of this study was to assess the production potential of field-grown, pollen-free sunflowers in the Mississippi environment. The stem length, stem diameter, and bloom diameter of the sunflower cultivars were assessed over six planting dates during the summer growing season to determine cultivar market potential. All the single-stem cultivars produced stem diameters greater than 1.4 cm and were too large for general florist usage. The stems and flowers of the branching cultivars were smaller than the single-stem cultivars, and were a better size for many floral arrangements. The yield of stems from the branching cultivars ranged from three to 13 stems per plant over six planting dates. In the branching group, the dark-flowered cultivars produced the greatest number and the longest stems in the trial. Yellow/gold-flowered branching sunflowers in this trial did not produce as many stems and the stem lengths were shorter compared to the dark-flowered sunflowers.
Urban soils are often not ideal planting sites due to removal of native topsoil or the mixing of topsoil and subsoil at the site. Adding pine bark based soil amendments to a clay soil altered soil bulk density and soil compaction which resulted in improved plant growth. Addition of nitrogen (N) or cotton gin waste to pine bark resulted in improved plant growth compared to pine bark alone. Growth of pansies (Viola × wittrockiana) during the 1999-2000 winter growing season was enhanced by the addition of pine bark plus nitrogen at 3- and 6-inch (7.6- and 15.2-cm) application rates (PBN3 and PBN6) and pine bark plus cotton gin waste at the 6 inch rate (CGW6). Plant size and flower production of vinca (Catharanthus roseus) were reduced by pine bark amendments applied at 3- or 6-inch rates (PB3 or PB6). Crapemyrtle (Lagerstroemia indica) grown in plots amended with 3 or 6 inches of pine bark plus cotton gin waste (CGW3 or CGW6) and pine bark plus nitrogen at 3- or 6-inch rates (PBN3 or PBN6) produced greater shoot growth than other amendment treatments. In some instances PB3 treatments suppressed growth. High levels of N and soluble salts derived from CGW and PBN soil amendments incorporated into the soil probably contributed to the improved plant growth observed in this experiment.
Seventeen plant bed fertilizer treatments including different rates of N, P, and K were evaluated for the effect on plant production and sweetpotato yield. `Beauregard' storage roots were bedded. Treatments were 0, 40, 80 lb N/ac; 0, 80, 160 lb P/ac; or 0, 75, 150, and 300 lb K/ac. Each nutrient was evaluated in a separate trial. After the first cutting, half of the N treatments and all P and K treatments had 40 lb N/ac top-dressed on the beds. For the first cutting the high rate of N (80 lb/ac) had a higher green weight than the low rate of 0 lb/ac. There wer no other differences found in the first or second cuttings for plant production or yield. Plant bed fertilization also had no effect on transplant survival.
One hundred U.S. sweetpotato [Ipomoea batatus (L.) Lam.] plant introductions (PIs) and four control cultivars were screened for insect injury in 1993. Of the least injured by insects, 56 and 31 were tested again in 1994 and 1995, respectively. Among control cultivars, the most highly resistant was `Regal' (moderately resistant), followed by `Beauregard' (susceptible), `Centennial' (susceptible), and `Jewel' (susceptible). Stem and root injury by the sweetpotato weevil (SPW) [Cylas formicarius elegantulus (Summers)] and root injury by the wireworm (Conoderus sp.)–Diabrotica sp. (cucumber beetle)– Systena sp. (flea beetle) (WDS) complex were measured. SPW stem injury was less severe (P ≤ 0.05) in 1994 and 1995 in PIs 508523, 531116, and 564107 than in control cultivars. PIs 508523 and 531116 also suffered less SPW root injury than did `Regal'. In the six PIs with least SPW root injury, PIs 538354, 564149, 508523, 538286, 531116, and 564103, 70% to 85% of the roots were not injured compared with 36% in `Regal' and 6% in `Jewel'. SPW root injury scores (0 = no injury; 5 = severe injury) in those PIs averaged 0.5 vs. 2.3 for `Regal'. Only in PI 538286 was WDS injury to roots less than in `Regal' over 2 years. However, eight additional accessions suffered less WDS injury than `Regal' in 1995 and four of those were among the six with least SPW injury. The lower levels of combined insect injury found in these four PIs (compared to `Regal') show that PIs have potential use for increasing insect resistance in sweetpotato improvement programs.