This experiment was conducted to determine peach harvest delay, quality, and storage life by ReTain. ReTain was applied to `Loring' at 50 ppm at 17, 14, 12, 10, or 7 days before harvest (n = 4). Fruit were harvested based on conversion of ground color to yellow over five dates at 3- to 4-day intervals in July. Fruit were segregated into five size classes, counted, and weighed. Ten fruit were randomly selected from the 2.5-in. size class, and fruit quality was measured at harvest and after 5 days at 20 °C. Some fruit were stored for 5 days at 4 °C, removed from storage, and fruit quality measured 4 h after removal. Harvest date was not affected by ReTain. Firmness was higher for fruit held at 5 days in cold storage with earlier treatment application but not at harvest or after 5 days at room temperature, although the trend at harvest was similar to the 5-day storage data. Soluble solids were not affected at harvest, after storage or after 5 days at room temperature. Red blush was slightly less at harvest and after 5 days in cold storage with earlier application rates, but differences disappeared after 5 days at room temperature. Yellow color was higher with earlier application date after 5 days of cold storage but not at harvest or after 5 days at room temperature. These results indicate that ReTain may have some utility for improving peach firmness at harvest, but there was no benefit of harvest delay at the rates applied in this study.
In 1999, two studies were conducted using bell pepper (Capsicum annuum L.) Study one evaluated the effect of three different mulch systems and bare soil (BS) on day and night temperatures encountered during the early growth, flowering, and fruit set period. Mulch systems were black plastic (BP), black plastic over white plastic (BOW), and minimum tilled rye (MTR). Study two evaluated the use of a 30% shade fabric on black plastic produced bell pepper. In study one, maximum daytime temperatures during the pre-flowering phase was significantly higher for MTR, 35.9 °C, compared to, 33.3, 32.5, and 32.1 °C for BOW, BP, and BS respectively. During early fruit set and fruit development, MTR was 36.9 °C, compared to 35.6, 34.9, 34.9 °C for BWP, BS, and BP respectively. Minimum nighttime temperatures were not significantly different between treatments. Bloom numbers and fruit set were adversely affected by MRT and were significantly lower than other treatments 23 and 15 days prior to harvest. Marketable weight and number of fruit per plot were significantly lower at harvest for MRT, 2.5 kg compared to 15.7, 14.5, and 11.6 kg for BWP, BP, and BS respectively. In study two, 30% shading 15 days prior to harvest resulted in 40% increase in number, 101 and 72, and weight, 21 and 15 kg, of marketable fruit for shaded area compared to nonshaded area respectively. Numbers of culls per plot, predominately sunburned fruit in non-shaded area, were reduced 72% by shading. The potential for developing systems to improve bell pepper production in Alabama are feasible based on these studies.
A clear polyester plastic was evaluated to determine if its physical properties were suitable for vegetable plasticulture. Integrity of the clear plastic was greatly reduced if edges were damaged or torn, resulting in ripping during the mulch lading process. All six punching devices evaluated for planting holes performed well on the black plastic. Flame burner rated highest for the clear plastic and the lowest rating was achieved with the standard transplanter wheel punch. Clear plastic deteriorated quickly and by 78 days after laying was brittle. Where paint treatments provided adequate coverage, deterioration was greatly reduced. Weed growth under clear plastic was a problem early, but weeds soon died due to heat accumulation under the clear plastic. Despite a lower cost, limited agricultural use could be made of this material.
Field performance, ear characteristics and sensory ratings were determined for `Even Sweeter,' `Fantasia', `Silver Queen', `Silverado', `Snow Belle', `Snow White', `Starshine', and `Treasure' sweet corn varieties. Yield (P = 0.60), ears per hectare (P = 0.77), and ear fill (P = 0.22) were not significantly affected by variety, whereas ear set height (P < 0.01), ear length (P < 0.01) and diameter (P < 0.01), tip cover (P < 0.01), eye appeal (P < 0.01), as well as sensory ratings of appearance (P < 0.01), sweetness (P < 0.01), and flavor (P < 0.01) after cooking were. None of the selected varieties was rated unacceptable. However, because mean separation tests at the 5% and 10% levels did not provide clear groupings and because all attributes have to be considered together in variety evaluation, a global performance index (GPI) was developed by adding the ranks of each variety for each attribute. GPI ranged between 28 for `Treasure' and 59 for `Snow White' on a 10 (best) to 80 (worse) scale. `Treasure', `Silver Queen', and `Even Sweeter' were above average. These varieties may be considered best performers for white sweet corn production in central Alabama.
Ethrel [(2-chloroethyl)phosphonic acid] was applied at 0, 100 or 200 ppm (mg·L-1) for 3 years to the early maturing `Empress' peach [Prunus persica (L.) Batsch] to determine if bloom delay by Ethrel reduces fruit weight at harvest. Trees were hand thinned at 0 or 3 weeks after full bloom to equalize cropload across Ethrel treatments and to determine if any reduction in fruit weight by Ethrel can be compensated by harvest with earlier thinning. Ethrel at 200 ppm (mg·L-1) delayed bloom by 3, 0, and 7 days in 1994, 1996 and 1997, respectively. Despite bloom delay, Ethrel did not delay harvest or reduce fruit weight. Thus, earlier hand thinning was not necessary. Ethrel did not affect blossom density and was not phytotoxic to vegetative or reproductive organs. These results indicate that even with the shorter fruit growth period of early maturing peach cultivars such as `Empress', there is sufficient time for fruit growth to recover on Ethrel treated trees so that fruit weight at harvest is not reduced.
Twelve peach rootstocks including `Lovell', `Nemaguard', `Flordaguard', `14DR51', five `Guardian' (BY520-9) selections, and three BY520-8 selections, were evaluated under field conditions to determine their effect on performance of `Cresthaven' peach. The trees were planted in 1994. Trunk cross-sectional area of BY520-8 selections SL1923 and SL4028 was 28% larger than the rest of the rootstocks, which were similar. There was no crop in 1996 due to late spring frost. Yield in 1997 and 1998 was higher for SL1923 because of higher cropload than the rest of the rootstocks, which were similar. Yield efficiency varied across years and rootstocks. Fruit weight varied among rootstocks but all were commercially acceptable. Harvest date was advanced by two days for some rootstocks compared to Lovell and none were delayed. Percent red blush, soluble solids and firmness varied among rootstocks, but none demonstrated superior quality in all of these parameters as compared to Lovell. Ring nematode population densities were above the threshhold considered to be critical for onset of PTSL for all rootstocks in 1997 and 1998. Tree survival was at or above 86% for all rootstocks and death was not correlated with ring nematode density No trees developed symptoms characteristic of Peach Tree Short Life disease complex. Guardian selections performed adequately compared to the commonly used commercial rootstocks in this study, however, the yield date are from 2 years only.
Vitamin C (VC) levels (mg/l00 g FW) were determined in 10 varieties of colored bell pepper grown under different field conditions. VC was determined by the microfluorometric method. `Orobelle' (169 mg), `King Arthur' (143 mg), `Valencia' (141 mg), and `Chocolate Bell' (134 mg) had significantly higher VC levels than `Dove' (109 mg), `Ivory' (106 mg), `Blue Jay' (93 mg), `Canary' (90 mg), and `Black Bird' (65 mg). The largest variability (53 mg) in VC levels were observed for varieties that had the highest VC content. Mean VC levels were 143a, 143a, 141a, 136a, 108ab, 93bc, and 63c for the yellow, red, orange, brown, white, purple, and black colors, respectively. Since the Recommended Daily Allowance (RDA) for VC is 60 mg per day, these results suggested that a 100-g serving of fresh bell pepper or less would supply 100% RDA of VC. Therefore, after selecting a color, growers still have the freedom to grow a variety that performs well in their area to produce peppers of high VC contents.
Effects of Tergitol-TMN-6 surfactant on blossom thinning (fruit set), fruit quality, and yield were studied in different cultivars of peach (Prunus persica [L.] Batsch) during 2003 to 2005, and in one cultivar of nectarine Prunus persica [L.] in one orchard and one cultivar of plum (Prunus domestica [L.]) in two orchards in 2004. In addition to Tergitol-TMN-6, effects of Crocker's fish oil (CFO) alone in three peach cultivars or in combination with lime sulfur in a nectarine cultivar were studied on fruit set, quality, and yield. Tergitol-TMN-6 at 5 mL·L–1 or higher rates, applied at about 75% to 85% bloom, reduced fruit set without russeting peach fruit. Peach fruit size was often increased by Tergitol-TMN-6 treatment. Applications of Tergitol at 20 mL·L–1 or 30 mL·L–1 excessively thinned peaches. Tergitol-TMN-6 at all rates burned foliage, but the symptoms disappeared after a few weeks without any adverse effects on tree productivity. Tergitol-TMN-6 at 7.5 mL·L–1 or 10 mL·L–1, applied either once at about 80% to 85% bloom or twice at 35% bloom and again at 80% to 85% bloom, reduced fruit set without any fruit russeting in nectarine. Tergitol-TMN-6 at 7.5 mL·L–1 to 12.5 mL·L–1 reduced fruit set in `Empress' plum. CFO at 30 mL·L–1 was effective in blossom thinning of some peach cultivars. A combination of lime sulfur and CFO was not effective in blossom thinning of nectarine. Considering results from several orchards in different locations in the Pacific Northwest over 3 years, Tergitol-TMN-6 is an excellent blossom thinner for peach, nectarine, and plum at rates of 7.5 to 12.5 mL·L–1, sprayed at a spray volume of 1870.8 L·ha–1 when about 75% to 85% blooms are open.