Ripening pawpaw [ Asimina triloba (L.) Dunal] fruit exhibit climacteric peaks of ethylene and CO 2 production 48 to 72 hours after harvest, and thus may be considered climacteric. The development of desirable quality traits and the loss of fruit firmness during ripening is extremely rapid, and a variety of strategies to slow these processes via manipulation of ethylene production and/or response and by more direct techniques like postharvest heat treatment have been attempted. Fruit, branches with fruit, and/or whole trees have been sprayed with ethephon or aminoethoxyvinylglycine to hasten or delay ripening, respectively. After harvest, fruit have been treated with commercial and higher rates of 1-methylcyclopropene for various durations at ambient and cold storage temperatures. Fruit have also been heat-treated at various temperatures, using both brief “shock” treatments above 40 °C and longer periods at 35 °C to 40 °C. In addition, in an attempt to alleviate the loss of ripening capacity as well as the development of injury symptoms from cold storage for longer than 4 weeks, cold-stored fruit were warmed to ambient temperature intermittently and then returned to cold storage. While some effects of the treatments were noted, the responses to all of these treatment strategies have failed to appreciably alter fruit ripening, the rapid loss of firmness, or otherwise maintain fruit quality beyond that without treatment.
has a small horticultural program and with that labor must be utilized as efficiently as possible.Each year the program grows approximately 2800 hardy garden chrysanthemums and follows recommended cultural scheduling and practice of pinching 7 to 10 days after planting.To reduce labor costs, a treatment of pinching at planting time was incorporated.Four Yoder cultivars of Dendranthema morifolium were used: ÔBethanyÕ, ÔFoxy MarjorieÕ, ÔMarjorieÕ, and ÔOkraÕ.All cultivars were in the late-season extender category and either medium or tall in height.Rooted cuttings were planted in Mycorise Pro-Mix substrate in an 8-inch bulb pan on 8 June 2007.A total of 240 rooted cuttings were planted for each cultivar, 120 for control and 120 for treatment.The plants were then placed in randomly assign blocks of 40 plants.Two measurements were used to assess plants' reaction to control and treatment pinch timing: area index (h w 1 w 2 ) and flower bud count.Final measurements were taken 16-19 Sept. 2007.Flower bud count was assessed by randomly selecting five plants per block and photographing the plant.Photographs were imported into Microsoft Ò Paint and counted.ÔMarjorieÕ was the only cultivar with a significantly larger area index for the control at P # 0.001.There were no significant differences in flower bud count.Results from this initial research project will influence future production practices at Murray State University for growing chrysanthemums.
Although the interest in and production acreage of organic fruit and vegetables has grown in recent years, there are questions about the viability of perennial crops such as apple ( Malus × domestica ) in an organic system in Kentucky because of the long, hot, and humid growing season. Thus, the objective of this project was to assess the severity of the challenges to organic apple production in Kentucky. A high-density, organic apple orchard was established in 2007 in the University of Kentucky Horticultural Research Farm in Lexington. The orchard of apple scab ( Venturia inaequalis )–resistant ‘Redfree’, ‘Crimson Crisp’, and ‘Enterprise’ trees on ‘Budagovsky 9’ (B.9) rootstock, trained in a vertical axis system, was managed using organically certified techniques and materials for disease and insect control since its inception. Tree growth, tree and fruit injury from insect pests and diseases, and yield over the period 2011–13 were studied. Periodic, shallow cultivation kept the ground beneath the trees free of vegetation once the lower limbs were pulled up and away from the path of the equipment. Vole ( Microtus sp.) damage was a continuing problem despite the use of trunk guards and cultivation to remove habitat around the trees. Total fruit yield ranged from 1.2 to 8.1 kg/tree across years and cultivars, with the marketable proportion of the total yield averaging 68% for Redfree and 43% for Crimson Crisp and Enterprise over the 3-year period. The unmarketable fruit exhibited a high incidence of plum curculio ( Conotrachelus nenuphar ) damage, with generally less damage from codling moth ( Cydia pomonella ) and sooty blotch ( Glosodes pomigena )/flyspeck ( Schizathyrium pomi ). In addition, in two of the three seasons, ‘Crimson Crisp’ and ‘Enterprise’, which were harvested at later calendar dates then ‘Redfree’, had significant levels of powdery mildew ( Podosphaera leucotricha ) injury, ‘Enterprise’ had significantly greater bitter rot ( Glomerella cingulata ), and ‘Crimson Crisp’ showed fruit and foliar damage from cedar apple rust ( Gymnosporangium juniperi-virginianae ). Because ‘Redfree’ was the only cultivar with an acceptable marketable proportion of the fruit crop, the use of early ripening disease-resistant apple cultivars may have the greatest potential for successful organic apple production in Kentucky and the surrounding region.
Volatile compounds, commonly produced by flowers during bloom, have been described as insect attractants. Some of these compounds stimulate Pinus pollen germination in vitro (French et al., 1979, J. Agric. Fd. Chem., 27184-187), suggesting that such compounds may do the same in vivo. Red Delicious apple pollen was germinated on agar in a simple, enclosed in vitro bioassay system in the presence of a number of plant tissues, including apple, tomato, and chrysanthemum leaves, apple flowers, rose petals, and apple fruit slices. These tissues represent a diversity of types of volatile compounds, Pollen germination was recorded by microphotography after 1 and 2 hours, and percent germination was determined. Although stimulation of germination was not observed, macerated tomato leaves inhibited it. To determine if the volatile characteristics of cultivars differ, flowers of Red Delicious and Golden Delicious apple were harvested at full bloom. Their volatiles were collected, identified, and quantitated by capillary GC-MS. Among 8 major compounds common in the two cultivars, several quantitative differences were observed. These results will be discussed in relation to the potential role of volatiles in pollen germination.
Volatile compounds were collected by porous polymer trapping from Golden Delicious apples (Malus domestica Borkh.) that had been heat-treated for 4 days at 38 °C, a treatment developed to reduce physiological and pathological disorders during storage, and then stored at 1 °C. Heat treatment of apple fruits markedly inhibited emission of total volatile esters (compounds commonly associated with apple aroma) and total volatiles (comprised principally of the volatile esters and α-farnesene) of apple within 1 day of treatment. However, after an extended refrigerated storage at 1 °C, the heat-treated fruit recovered and produced more total volatiles, increasing from 4% compared to non-heat-treated fruit directly after heat treatment to 145% of non-heat-treated fruit after 6 weeks of storage. Total volatile production of non-heat-treated fruit declined over 5-fold during the 6 weeks of cold storage, while that of heat-treated fruit increased over 6-fold. Total volatile esters from heat-treated fruit declined after 1 week of storage but had increased 4-fold from the initial sampling date after 6 weeks of storage. The heat treatment effect on emission of volatile compounds was observed immediately following heat treatment. The fruit cuticle and epidermis were not barriers to volatile emission by heat-treated fruit since slicing both heat-treated and non-heat-treated fruit after treatment resulted in total volatile yields similar to intact fruit. Heat treatment apparently temporarily inhibited but did not destroy, or destroyed but allowed resynthesis of, the enzyme systems catalyzing volatile compound synthesis as shown by increasing emission over time by heat-treated apples. Keywords: Esters; postharvest storage; flavor; Malus domestica
Horticulture plays an integral role in human existence. As foods, in interior surroundings and exterior landscapes, and in forms of artistic expression, there is no social group worldwide for whom horticulture has not played a profound role [1]. Horticultural plants and their products provide critical nutrition and nutraceutical compounds which sustain life, provide environments for leisure, recreation, and improved mental health, and play essential roles in ecology and biodiversity. As the population grows, horticulture is destined to play increasingly critical roles in maintaining human health and happiness.[...]
were collected from field-grown trees ‘at full bloom. With the exception of the rose petals, all tissues were tested either intact or macerated by light grinding in a mortar and pestle. In addition, to determine if ethylene released upon maceration had an effect, intact tomato leaves were dipped in 1000 ppm 2-chloroethyl phosphonic acid (ethephon) before bioassay. After 2 h, microphotographs ( × 40) of the pollen were taken. Four fields from each agar block were photographed. Total and germinated pollen grains were counted from the photographs, recording only single grains on the agar surface. Grains were classified as germinated when the pollen tube length exceeded the diameter of the grain. Percent germination values were derived for each treatment and tested by analysis of variance. After determining that data transformation was not necessary, treatments means were compared by Dunnett’s test.
