A procedure for the regeneration of muskmelon (Cucumis melo L.) cv. Topmark via shoot organogenesis from cotyledon explants is described. The best induction medium for a morphogenic response was MS salts and vitamins medium with BA at 1.0 mg·liter-1. Further vegetative bud development was completed by transferring organogenic tissue to MS medium containing BA at 0.05 mg·liter-1 . The shoots were rooted in MS medium containing NAA at 0.01 mg·liter-1. Morphologically normal plantlets were obtained. Chemical abbreviations used: 6-benzylaminopurine (BA); indoleacetic acid (IAA); naphthaleneacetic acid (NAA).
Harbans L. Bhardwaj
Winter legume cover crops have been successfully used to meet N needs of many summer crops, but they are not being used extensively in Virginia and the mid-Atlantic region, especially for specialty crops such as muskmelon and sweet corn. The objective of these studies was to determine the potential of winter legume cover crops in meeting N needs of muskmelon (Cucumis melo L.) and sweet corn (Zea mays L.). Comparisons of performances of muskmelon and sweet corn, grown after lupin (Lupinus albus L.), hairy vetch (Vicia villosa Roth.), Austrian winter pea ([AWP] Pisum arvense L.), and control fertilized with 112 kg N ha–1, and unfertilized control were made during 1999, 2000, and 2001. The interactions between cover crop treatments and years were, generally, significant. The muskmelon fruit yields were 53.6, 45.0, 23.1, 13.0, and 5.6 Mg·ha–1 during 1999; 27.8, 26.3, 8.6, 5.8, and 2.2 Mg·ha–1 during 2000; and 41.1, 39.9, 25.5, 21.4, and 2.1 Mg·ha–1 during 2001 respectively for lupin, hairy vetch, AWP, 112 kg N ha–1, and control. Similar results were obtained for number and size of muskmelon fruits. The sweet corn ear yields (Mg·ha–1) were 8.5, 5.6, 3.1, 1.5, and 0.7 during 1999; 5.2, 3.9, 4.0, 4.8, and 1.2 during 2000; and 2.6, 2.4, 1.9, 2.0, and 0.9 during 2001, respectively for lupin, hairy vetch, AWP, 112 kg N ha–1, and control. White lupin and hairy vetch, as winter cover crops, were superior than AWP and 112 kg N ha–1 for sweet corn ear number and size, and plant height. These results demonstrated that winter legume crops, especially lupin and hairy vetch, can be excellent winter cover crops for meeting N needs of muskmelon and sweet corn.
S. Alan Walters and Jonathan R. Schultheis
Two field studies were conducted in 1997 (Clinton, N.C.) and 1998 (Carbondale, Ill.) to determine if replanting (at 1, 2, 3, or 4 weeks after the initial seeding) into stand deficiencies of 10%, 30%, and 50% affected `Athena' muskmelon (Cucumis melo L. var. reticulatis) melon size and yield. Muskmelon numbers were higher for 1997, but there was no interaction of treatment by year for any of the melon sizes (small, medium, or large) or total melon number. Based on the two experiments conducted, `Athena' muskmelons stand deficiencies up to 30% do not reduce total or marketable numbers compared to a complete stand. Replanting into 10%, 30%, and 50% stand deficiencies increases early-season melon numbers regardless of the replant times. For main-season and total-season harvests, there was no advantage of replanting into 10% deficient stands and in most cases, replanting reduced total and marketable melon numbers. In the 1997 experiment, replanting into 30% and 50% stand deficiencies improved yields but this did not occur in the 1998 experiment. Based on this information, `Athena' muskmelon should be replanted only if a field has a stand reduction of more than 30%. Melon numbers were generally higher if replanted in 1 or 2 weeks after the initial seeding compared to 3 or 4 weeks. However, the timing of replanting does not appear to have significant influence on total or marketable melon numbers.
Ernest R. Terry Jr., William M. Stall, Donn G. Shilling, Thomas A. Bewick, and Steven R. Kostewicz
Studies were conducted to determine the critical period of smooth amaranth interference in watermelon (Citrullus lunatus L.) and muskmelon (Cucumis melo L. var. reticulatus). Best-fit linear or exponential regression models were used to predict the maximum period of competition and the minimum weed-free period for 10% yield loss. The maximum period of competition and minimum weed-free period was 0.50 and 2.97 weeks after watermelon emergence, respectively, and 1.0 and 3.9 weeks after muskmelon emergence, respectively. The critical periods of smooth amaranth interference for the crops were between those intervals. In both crops, late emerging smooth amaranth had little effect on total yield. Smooth amaranth introduced at crop emergence reduced total yield. The effect of competition on yield components, i.e., fruit number per hectare and fruit mass, varied by crop. Muskmelon fruit count was more sensitive to smooth amaranth competition than was watermelon fruit count. Conversely, mass per fruit of muskmelon was less sensitive to this competition than was mass per fruit of watermelon.
Hypodermal mesocarp disks from abscised muskmelon fruits (Cucumis melo L. var. reticulatus Naud.) were floated in 0.00, 0.04 or 0.16 M CaCl2 plus 0.35 M mannitol at ′20C in the dark for 10 days. Changes in chlorophyll, protein and total phospholipids all indicators of membrane senescence were assayed. The catabolism, percent retention, of chlorophyll, protein and total phospholipids was delayed by 0.04 M Ca, but accelerated by 0.16 M compared to no Ca. Loss of membrane integridity, increased free sterol: total phospholipid (umol./umol.), was delayed by 0.04 M Ca, hut accelerated by 0.16 M compared to no Ca. The degree of lipid saturation was inconclusive between Ca treatments. Muskmelon fruit disks membrane lipid degradation is slowed by 0.04 M Ca but accelerated by supraoptimal 0.16 M Ca treatment.
Gene E. Lester
Analyses of sensory attributes from 19 netted muskmelon (Cucumis melo L.) cultivars and breeding lines showed that flavor, (r= .92) had the highest significant correlation with overall fruit acceptance, while appearance (r = .72), color (r = .71) and internal color (r = .68) were secondary, and texture (r = .41) was not significantly correlated with overall fruit acceptance. Chemical attributes of soluble solids, fresh weight, dry weight, beta-carotene, firmness, fructose, glucose, sucrose, and total sugars shoved that total sugars per g fresh weight had the highest significant correlation (r = .68) with overall fruit acceptance. Total sugars per g fresh weight was significantly correlated with flavor (r = .65). Although, sugars were correlated with flavor, sugars when compared to flavor were less important in determination of overall muskmelon fruit preference.
G.R. Panta and D.S. NeSmith
Eight muskmelon (Cucumis melo reticulatus L.) cultivars were selected to test whether a model could be developed to estimate leaf area across cultivars. Regression analyses of leaf area vs. leaf width and length revealed several models that could be used for estimating the area of individual muskmelon leaves. A linear model using leaf width squared was the best overall, yielding the equation A = 3.3 + 0.63 (W2), where A is area of an individual leaf lamina (square centimeter) and W is leaf width (centimeter) at the widest point perpendicular to the leaf midrib. Forcing the intercept through the origin did not significantly alter prediction capability and resulted in a simple model of the form A = 0.64 (W2) that was applicable to all eight cultivars.
Henry G. Taber
Black, clear, and wavelength-selective IRT 76 plastic mulches with or without clear, slitted, hooped rowcovers were evaluated for early muskmelon production in 1991 and 1992. Clear and IRT 76 plastic mulches tripled early yield, compared with bare ground, 130 and 45 cwt/acre, respectively. Highest yields both years were from the combination of rowcover with either clear plastic or IRT 76 mulch-181 cwt/acre in 1991 and 379 cwt/acre in 1992. Yield from clear plastic was superior to that from IRT 76 by 41 cwt/acre in 1991, but not in 1992. The minimum soil temperature for IRT 76 compared with clear plastic was +0. 5F and -2F for 1991 and 1992, respectively. Crop rotation and herbicides were used to provide adequate weed control both years. The best cost-effective early muskmelon production system tested involved clear plastic, rowcovers, and trickle irrigation.
Warley M. Nascimento and Sherlie H. West
The effects of seed priming on seedling development of muskmelon (Cucumis melo L.) under laboratory and greenhouse conditions were studied. Seeds of `Top Net, SR' muskmelon were primed for 6 days in darkness at 77 °F (25 °C) in KNO3 (0.35 m) aerated solution. After germination in petri dishes at 77 °F, primed and nonprimed seeds were transferred to either paper towels (laboratory study) or trays, which were placed in greenhouse conditions. Leaf area and fresh and dry mass of roots and shoots were measured at 15 and 30 days. In germination under laboratory conditions, primed seeds germinated ≈16 and 60 hours earlier than nonprimed seeds at 77 °F and 63 °F (17 °C), respectively. Priming caused no beneficial effect on shoot and root development either in laboratory conditions or during transplant production in the greenhouse.
George E. Boyhan and Joseph D. Norton
Muskmelon (Cucumis melo L.) breeding line AC-82-37-2 was identified as having resistance to alternaria leaf blight caused by Alternaria cucumerina (Ell. and Ev.) Elliot. An analysis of this resistance with a three-factor scaling test indicated that both additive and dominance effects were highly significant. The x2 value indicated that there were epistatic effects as well. The six-factor scaling test revealed no significant dominance effect, but the additive and homozygote × heterozygote epistatic interaction effects were highly significant.