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- Author or Editor: William H. Swallow x
Abstract
Two characteristics of perennials which distinguish them from annuals are that they live longer and tend to be larger. It turns out that much of what needs to be said about experimentation with perennials follows from these 2 trivial observations and their consequences.
Mature green `Grande Naine' bananas (Musa AAA) were harvested 13 weeks after flowering in June and Sept. 1993 and Feb. and Mar. 1994 and were sent air freight to Raleigh, N.C. Fruit were held under 1) storage (36 days at 14 C and 80% to 90% relative humidity) or 2) ripening (8 days storage, followed by ethylene treatment on day 8 and subsequent storage at 17 °C and 80% to 90% relative humidity). Despite of similar grade and age, length of the preclimacteric phase (green life) was different between fruit harvested at different times of the year. Fruit harvested in February and March had a longer green life than those harvested in June and September. Rate of respiration best described changes that occurred during the postharvest life of bananas; however, variables such as pulp pH and soluble solids could be commercially useful measures. Once gassed with ethylene, ripening rates were similar between all four lots of fruit, indicating that seasonal variation probably doesn't contribute much to variability seen during ripening. Hand position in the bunch did not have a large influence on variability during ripening or storage.
Abstract
‘Jewel’ sweet potatoes [Ipomoea batatas (L.) Lam.] were grown during 2 seasons to evaluate 3 N sources, 3 K rates, and 2 N rates on a sandy loam soil. Nitrogen source did not influence yield; however, NaNO3 significantly increased foliar and root Na concentrations over those obtained with NH4NO3 or Ca(NO3)2. Higher yields were obtained with 140 kg K/ha than with 70 or 280 kg K/ha and 101 kg N/ha than with 202 kg N/ha. No foliar or root mineral concentrations were deficient. Nitrogen, P, Ca, and Mg concentrations were lower in root than foliar tissues.
Fertilizers with a high proportion of nitrogen (N) in the nitrate (NO3 –) form are used in the ornamental industry to promote compactness in plants. Although the common belief is that it is the high proportion of NO3 – that causes compactness, these formulations also contain no or a low level of phosphate, which can also cause compactness. This study was conducted to assess the relative effects of NO3 – to ammonium (NH4 +) ratio and phosphate supply, as found in high NO3 – fertilizers, on seedling shoot growth. A series of fertilizers was formulated in which the level of phosphate and proportion of N in the NO3 – form were varied factorially. Additionally, commercial fertilizers varying in these same two nutrient components were tested to verify the results obtained using the formulated fertilizers. Test plants included gomphrena (Gomphrena globosa L.), impatiens (Impatiens wallerana Hook. F.), petunia (Petunia ×hybrida Juss.), marigold (Tagetes erecta L.), and tomato (Solanum esculentum Mill.) grown as plug seedling crops. A strong inverse relationship occurred between the supply of phosphate and extent of compactness. The relationship between proportion of N in the NO3 – form and compactness was comparatively small. In most comparisons within the study, shoot size increased with increasing proportion of NO3 –, contrary to common belief. These data indicate that it is the limited phosphate level in high NO3 – fertilizers that accounts for compactness rather than the high proportion of N in the NO3 – form.
Bell peppers (Capsicum annuum L.) are classified as nonclimacteric fruits while some hot peppers have been reported as climacteric. Responses of peppers to exogenously applied ethylene-releasing compounds suggest ethylene involvement in the ripening process. Ethylene production and respiration rates in 13 cultivars of pepper: `Camelot', `Cherry Bomb', `Chiltepin', `Cubanelle', `Banana Supreme', `Habanero', `Hungarian Wax', `Mesilla', `Mitla', `Savory', `Sure Fire', `Tabasco', and `King Arthur' were studied under greenhouse and field conditions. Fruit from each cultivar were harvested at different maturity stages determined by color, ranging from mature-green to full red-ripe. Carbon dioxide and ethylene production were measured by gas chromatography. Both variables were significantly different among maturity stages for all cultivars. Respiration rates were between 16.5 and 440.3 mg·kg-1·h-1 CO2. Ethylene production ranged from 0.002 to 1.1 μL·kg-1·h-1. Two patterns of CO2 production were identified: higher CO2 production for mature-green fruit with successive decreases for the rest of the maturity stages or lower respiration rates for mature-green fruit with an increase in CO2 production either when fruit were changing color or once fruit were almost totally red. A rise in CO2 production was present for most cultivars. Ethylene evolution increased significantly at maturity or before maturity in all cultivars except `Cubanelle' and `Hungarian Wax'. Respiration rates and ethylene production were significantly different among cultivars at the mature-green and red stages.
Pre-cooled bulbs of two dutch iris (Iris Ă—hollandica) cultivars, Ideal and White Wedgewood, were grown and harvested as cut flowers in four production systems in a tobacco (Nicotiana tabacum) transplant greenhouse from late October until late January in two consecutive production years (2000-01 and 2001-02). All production systems (lily crates, lay-flat bags, pots, and float trays) utilized the same commercial peat-vermiculite, tobacco germination substrate. Stems developed more quickly but were shorter and lighter in 2001-02 than 2000-01 due to warmer growing conditions. Stems grown in float trays were shorter and lighter than other treatments in 2000-01 but similar to the others in 2001-02. Stems grown in lay-flat bags flowered earlier with similar or greater stem lengths and fresh weights as the other systems. Stems of `White Wedgewood' were longer and heavier than `Ideal'. In general, `White Wedgewood' provided more consistent production than `Ideal' in both production seasons. An economic analysis in this study concludes that a grower is unlikely to make money growing dutch iris in a tobacco transplant greenhouse using these production systems unless there is a targeted local market.