Search Results

You are looking at 1 - 10 of 20 items for

  • Author or Editor: Melvin R. Hall x
Clear All Modify Search
Free access

Melvin R. Hall

Most commercial sweetpotato acreage in the United States is grown from plants that have been produced from bedded roots. Development of new methods or new combinations of known methods to increase plant production helps to maximize the number of usable plants produced in a minimum amount of time and also reduces propagation costs while aiding early transplanting. Plant production is influenced greatly by genotype, and many efforts have been directed at improving plant production from sparse plant producing cultivars. Modifications of wounding or cutting treatments, exposure to chemical sprout inducers, presprouting by heat treatments and combinations of these treatments have enhanced plant production from large and small roots of sparse and profuse plant producing cultivars.

Free access

Melvin R. Hall

In 1983-1987, a Gardner color difference meter standardized to a pink tile (L=70.5, a=+23.9, b=+9.3) and equipped with an aperture of 3.8 cm (1983-1986), 1.9 cm (1987), or 1.0 cm (1988-1989) was used to measure lightness (L) and intensity (chroma) of `Georgia Red' sweetpotato [Ipomoea batatas (L.) Lam.] seed roots cut into longitudinal sections. Individual roots were selected with good color when L<68 and chroma≥39 and fair color when L≥72 and chroma <35 (1983-1985), L<65 and chroma≥42 for good color and L≥80 and chroma <25 for fair color (1986), L≤66 and chroma≥41 for good color and L≥85 and chroma≤20 for fair color (1987). In each year, roots falling between the defined selection values were discarded. In 1988, root sections from a common 1983-ancestor parent root were bulked for plant propagation if L and chroma values were similar. Subsequent measurements of these bulk populations were made in 1989. Measurements by a color difference meter were helpful in making objective judgements in selecting for internal color of sweetpotato. Also, these measurements were helpful in following changes in internal color through several generations of vegetative propagation.

Free access

Melvin R. Hall

Plots grown from `Georgia Jet', `Red Jewel', and `Jewel' sweetpotato [I pomoea batatas (L.) Lam.] plants cut from the propagating bed (cut-plants) yielded more than plots grown from plants pulled from the bed (plants). Presence or absence of the shoot apex had little influence on yields of `Georgia Jet' and `Red Jewel' when evaluated in combination with plants or cut-plants or when evaluated in combination with vine cuttings transplanted in an upright or an inverted position. Chlorine dips did not influence yield of `Jewel' plants or cut-plants. Plots grown from `Red Jewel' vine cuttings transplanted in an inverted position generally yielded slightly less than plots grown from vine cuttings transplanted in an upright position, but these differences were not significant.

Free access

Melvin R. Hall

Immersion of sweetpotato [Ipomoea batatas (L.)] storage roots in low concentration (5 and 50 mg·liter-1) of gibberellic acid (GA) in solutions of benzyl adenine plus GA4+7 increased early but not total plant production from bedded roots of `Georgia Jet' and `Jewel'. Immersion in 0.5 and 1 mg·liter-1 solutions of GA3 increased early plant production from `Georgia Jet'. Neither weight nor visual appearance of the harvested plants nor root yield from transplants were influenced by gibberellin treatments of the bedded roots.

Free access

Melvin R. Hall

`Georgia Jet' and `Jewel' sweetpotato (Ipomoea batatas L.) roots were cured (32 ±C lC, 85% ± 5% relative humidity (RH)] for 7 days immediately after harvest and then subjected to 0, 4, 8, or 12 additional days of curing before storage (16 ± lC, 85% ± 5% RI-I). Roots were presprouted (32 ± lC, 85% ± 5% RH) for 0, 4, 8, or 12 days before bedding. Plant emergence of `Georgia Jet' was accelerated with increasing duration of curing, but emergence of both cultivars was accelerated with increasing duration of short-interval presprouting. With increasing duration of extended curing, there was a nonlinear increase in the number of early and total `Georgia Jet' plants. However, with increasing duration of presprouting, there was a linear increase in the number of early and total plants of both cultivars. Average weights of early and total `Jewel' plants were higher than those of `Georgia Jet' plants. Treatments did not influence deterioration of bedded roots or the number of sprouts remaining on roots of a cultivar after 9 weeks of plant harvest. However, `Jewel' roots retained more sprouts than `Georgia Jet' roots, possibly indicating greater capacity for continued production of plants from `Jewel' than `Georgia Jet' if additional plant harvests were conducted.

Free access

Melvin R. Hall

Sweetpotato [Ipomoea batatas (L.)] storage root yields were evaluated from ≈ 25-cm transplants. The shoot apex was either removed or not removed from pulled (underground stem retained) and cut (underground stem removed) `Georgia Jet' and `Red Jewel' plants. The shoot apex was not removed from pulled and cut `Jewel' plants on which the basal half was immersed or not immersed in calcium hypochlorite solutions. Cut plants of all three cultivars produced higher total marketable and U.S. no. 1 yields than pulled plants. However, neither removing the shoot apex from `Georgia Jet' and `Red Jewel' nor immersing the basal half of `Jewel' plants in calcium hypochlorite solutions improved yields.

Free access

Melvin R. Hall

`Red Jewel' sweetpotato [Ipomoea batatas (L.)] roots were cured [32 ± 1C, 85% ± 5% relative humidity (RH)] for 7 days immediately after harvest and cured for O. or 8 additional days before being stored (16 ± 1C, 85% ± 5% RH). Midway through storage, roots were heated (32 ± 1C, 85% ± 5% RH) for 0, 2, 4, 6, 8, 10, 12, or 14 days and placed back into storage. Before being bedded, roots were presprouted (32 ± 1C, 85% ± 5% RH) for O or 8 days. Plant emergence was accelerated with extended curing or presprouting and with increased midstorage heating duration. Early plant production increased with increasing duration of midstorage heating of roots not subjected to extended curing or presprouting. Eight days of extended curing eliminated response to midstorage heating; but, with 8 days of presprouting, a quadratic response to midstorage heating peaked at ≈ 8 days. However, when combined with midstorage heating, presprouting had more of an effect than extended curing on early plant production. Briefly extending curing, midstorage heating, and presprouting each independently increased the cumulative number of midseason plants, but only presprouting influenced total plant production. Treatments did not influence deterioration of bedded roots or number of sprouts <20 cm produced during 10 weeks of harvest.

Free access

Melvin R. Hall

Primary vine lengths of `Crimson Sweet' watermelon direct-seeded on 25 March and 24 April 1992 were 62 and 58 cm within 7 and 5 weeks, respectively. Lengths of replacement vines direct-seeded on 20 April and 14 May in the respective plantings were 6% and 5%) while transplants were 46% and 52% of these lengths. Total number of marketable fruit and total tonnage yield from late March plantings (suboptimal soil temperatures) in 1992 and 1993 were enhanced when missing hills were replanted either by direct seeding or transplanting. However, these measurements from late April plantings (optimal soil temperatures) were not influenced by missing hills or replanting methods in either year. Distribution of fruit sizes varied for the two years and there was no consistent pattern to indicate how fruit size influenced total number of marketable fruit or total marketable tonnage yield.