Abstract
Individual leaves of Cucumis melo L. acropetal to a developing fruit were treated with a pulse of 14CO2. The level of 14C in the leaves, internodes, and fruits was determined after various periods of time when the leaf at the 3rd node acropetal to the fruit was treated. Leaves at the same node as the fruit, the 2nd, the 3rd, the 6th, and the 18th node acropetal to the fruit were treated and the level of 14C in the leaf, internodes, and fruit was determined after 2 hours. The percent of the incorporated 14C which was exported from the leaf was strongly affected both by time and leaf position relative to the fruit. Leaves which were 3 nodes acropetal to the fruit exported 65% of the label in 6 hours, while those further from the fruit retained the label longer. The influence of the fruit on the movement of 14C label is limited to a few internode lengths along the branch.
Abstract
Natural cross pollination was studied with virescent (v), yellow-green (yg), glabrous (g) and halo (h) muskmelon mutants. The average percent crossing was 8.9,7.6,5.1, and 6.0, respectively. The variation was from 0.0 to less than 20%, except for one fruit with 30%.
Abstract
The muskmelon (Cucumis melo L.) breeding population Wisconsin (Wl) 998 was developed jointly by the U.S. Department of Agriculture, the University of Wisconsin, and Michigan State University to provide breeders and seedsmen with a source from which gynoecious inbreds can be developed for use in the production of hybrid cultivars. In addition to a high incidence of gynoecious plants, WI 998 provides other useful plant and fruit characteristics.
Abstract
‘Edisto’ and ‘Saticoy Hybrid’ muskmelon (Cucumis melo L.) were grown at 2 soil moisture levels. Soil moisture was negatively correlated with soluble solids content (SSC) in the fruit of both cultivars and negatively correlated with dry matter, ascorbic acid, β-carotene, and sucrose content in ‘Edisto’ and with ascorbic acid content in ‘Saticoy’. In both cultivars, SSC was highly correlated with ascorbic acid, sucrose, and dry matter content. The SSC, a commonly used measure of fruit quality, may be misleading unless the effect of soil moisture is considered.
Abstract
Combining ability and heterosis for yield, maturity, and plant traits in bush muskmelon (Cucumis melo L.) were estimated through the use of a 6-parent diallel evaluated in 1981 at Excelsior, Minn. and at Santa Paula, Calif. The variance of GCA was greater than that of SCA for all traits. Minnesota 266 was the best general combiner for yield weight characteristics. Minnesota 101 was exceptional for GCA in those traits associated with earliness, and U.C. Perlita Bush and U.F. G508 combined well for main crop yield. Correlations between the performance of parental lines and the average of their hybrids were consistently positive and often significant. Favorable heterosis over the midparent was found for all traits but days to first fruit. Favorable heterosis over the superior parent was found for plant health and all yield traits except total number of fruit per plant. In a 3 × 10 design II at Excelsior, estimates of additive variance exceeded those of dominance variance in general, providing for moderately high heritability estimates (40–70%) for most traits.
Abstract
A 6-parent diallel was established in 1981 at Excelsior, Minn, and at Santa Paula, Calif, to analyze combining ability and heterosis for fruit quality of traits in bush muskmelon (Cucumis melo L.). GCA variance exceeded SCA variance for all traits. Minnesota breeding lines were superior in GCA for most interior quality traits, but inferior to Florida and California lines in exterior quality. Correlations between the performance of parents and the average of their hybrids were consistently positive, and often significant. Favorable heterosis over the midparent was shown for soluble solids, net density, and net rope, and, to a lesser extent, for flesh amount, rind thickness, cavity amount, and cavity dryness. A 3 × 10 design II at Excelsior showed estimates of additive variance exceeding those of dominance variance for all traits except fruit weight, shape index, and vein tract. The large estimates of additive variance provided for moderately high (40–70%) estimates of heritability for most traits.
Field experiments were conducted over 4 years to evaluate the effects of antitranspirant (Folicote, Aquatrol Inc., Paulsboro, N.J.) and polyacrylamide gel (SuperSorb, Aquatrol Inc., Paulsboro, N.J.) on early growth of transplanted muskmelon grown either protected by tree windbreaks or exposed to seasonal winds. A randomized complete block design (RCBD) with split plot arrangement was used with wind protection (sheltered and exposed) areas as the main treatment and use of an antitranspirant spray or gel dip as subtreatments. Based on destructive harvests in the field, treatments and subtreatments did not affect dry weight or leaf area index in the first 2 years. Specific contrasts, however, showed that gel application significantly increased fresh weight, dry weight, and leaf area index over that of the untreated transplants whereas the spray application tended to reduce these factors during the first 3 weeks after transplanting. Significant differences between gel and spray subtreatments disappeared by 5 weeks after transplanting. Shelterbelts ameliorated crop microclimate thereby enhancing plant growth. Significantly, wind velocity at canopy height was reduced 40% on average and soil temperatures were about 4% warmer in the sheltered plots compared to the exposed plots during the first 5 weeks post-transplant. Muskmelon plants in the sheltered areas grew significantly faster than the plants in the exposed areas in 2 of the 3 years reported, with the 3-year average fresh weight increased by 168% due to wind protection. Overall transplanting success and early growth were enhanced the most by wind protection, followed by the polyacrylamide gel root dip, and least by the antitranspirant foliar spray. We conclude that microclimate modification by wind speed reduction can increase early muskmelon plant growth more consistently than the use of polyacrylamide gel as a root dip at transplanting or the use of an antitranspirant spray. A polyacrylamide gel root dip generally will provide more benefit during early muskmelon growth than the use of an antitranspirant spray.
Short-internode (SI) muskmelon (Cucumis melo L.) genotypes Ky-P7 (si-1 gene for SI) and Main Dwarf (si-3 gene for SI) were compared with the normal-internode (NI) cultivar Mainstream at various plant spacings or planting densities over 3 years. SI `Honey Bush' (si-1 gene for SI) and `Bush Star' (si-1 gene for SI) were included in 2 years. At double the population, SI plants (si gene type) produced ≈35% fewer fruit than `Mainstream' plants grown at one-half the population density. Spacing generally had no effect on average fruit weight, but increasing plant density of SI genotypes decreased the number of fruit per plant. Generally, doubling the density reduced leaf area and total plant dry weight, but had minimal effect on the amount of shaded leaf area. Ky-P7, `Honey Bush', and `Bush Star' plants had more leaf shading than `Mainstream' and Main Dwarf plants.
The southern root-knot nematode, Meloidogyne incognita [(Kofoid & White) Chitwood], causes serious economic losses to melon (Cucumis melo L.) production in the United States. The present study was conducted to determine if separable differences in nematode resistance of Cucumis melo could be found at some inoculum level. Five C. melo lines were compared with Cucumis metuliferus Naud. (C701A), a highly resistant species, for root necrosis, galling, egg mass production, and reproduction when inoculated at 0, 500, 1000, 2000, or 5000 nematode eggs per plant. Using these criteria, melon line C880 inoculated with 1000 eggs per plant was highly susceptible, while PI140471, PI 183311, and the cultivars Chilton, Georgia 47, Gulf Coast, Planters Jumbo, and Southland were less susceptible. In greenhouse tests with an inoculum level of 1000 eggs per plant, low levels of resistance were evident. A thorough screening of the available germplasm against M. incognita may identify higher levels of root-knot nematode resistance for incorporation into improved melon cultivars.