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- Author or Editor: R. W. Robinson x
Abstract
Soil application of (2-chloroe thyl)phosphonic acid (ethephon) strongly promoted pistillate flower formation of cucumber. Soil treatment had a prolonged effect, for plants transplanted 4 weeks after the chemical was added to the soil were greatly modified in growth and development.
Abstract
No significant resistance to verticillium wilt (Verticillium dahliae Kleb) was found in 59 eggplant (Solanum melongena L.) accessions, in a sexual hybrid between S. melongena and S. integrifolium, or in eight somatic hybrid clones between S. melongena and S. sisymbriifolium. A relatively high degree of resistance was observed in accessions of S. aculeatissimum, S. scabrum, and S. sisymbriifolium. All 58 accessions of S. gilo tested were susceptible, as were all accessions of S. incanum, S. integrifolium, S. laciniatum, S. macrocarpum, S. mammosum, and S. nodiflorum.
Abstract
In crosses between Cucumis sativus cv. Surinam, resistant to watermelon mosaic virus 1 (WMV-1), and the susceptible line Wisconsin 2757, resistance was inherited as a monogenic recessive. The symbol wmv-1-1 was assigned to the gene. ‘Surinam’ responds to WMV-1 infection with a mild systemic mottle, usually confined to 1 or 2 leaves.
Abstract
Yield of cucumbers (Cucumis sativus L.), grown in an isolated field where pollination was reduced by rogueing plants with staminate flowers, was increased by treatment with 50 or 100 ppm triiodobenzoic acid (TIBA). Parthenocarpic fruit development was induced in the greenhouse by treating plants with 0.1 - 100 ppm TIBA. The no. of fruit per plant and the site of parthenocarpic fruit development were dependent on growth regulator concn.
Abstract
Two rapid methods for estimating cucurbitacin C (Cuc C) in cucumber cotyledons are described. Both methods require a single cotyledon extracted with methanol. The filtered extract is injected into a C18 HPLC column with methanol-water (55:45) solvent, and quantitative estimates of Cuc C are obtained by UV detection at 254 nm. In the 2nd method, the extract is concentrated for spotting on silica gel TLC plates, the TLC plates are developed with ethylacetate : benzene (75:25), and visualized with vanillin-orthophosphate to give a semiquantitative estimate of Cuc C. The 2 methods are quick and suited for screening seedlings for cucurbitacin levels in segregating populations to select for cucumber beetle resistance and for nonbitter fruit.
Abstract
Isozyme phenotypes were used to identify two (P2 and P3) of the six monosomic alien addition lines that have been isolated from a Cucurbita moschata × C. palmata hybrid. Phenotype P2 displayed the C. palmata fumarase isozyme, whereas P3 exhibited two glucose phosphate isomerases and an aspartate aminotransferase derived from C. palmata. P2 also possessed the hard rind trait characteristic of C. palmata. Both the biochemical and the morphological phenotypes were inherited in a non-Mendelian fashion, and no recombination was observed within either the P2 or P3 set of characters. It was concluded that the loci coding fumarase and hard rind were situated on the alien chromosome in P2 trisomics and that the other three loci were on a 2nd C. palmata chromosome possessed by the P3 line. The loci responsible for other C. palmata isozymes either were not expressed or were not located on any of the five C. palmata chromosomes represented in the alien addition lines.
Abstract
EM VII, EM IX AND MM 106 apple rootstocks were grown under greenhouse conditions in cans containing soil-incorporated simazine at concentrations of 0–6 ppm. In general, except for severity of foliar injury, the rootstocks responded similarly to simazine. Least foliar injury occurred on MM 106 rootstocks and the most injury on EM VII. Fresh weight increases indicated, however, that this difference may be of no practical significance.
Simazine levels of 1 and 2 ppm improved above-ground growth and increased total leaf nitrogen (N) but suppressed root growth. At concentrations of 3 ppm and higher, simazine suppressed both above-ground growth and root growth but markedly increased leaf N.
Abstract
Shoot growth and fresh wt of greenhouse-grown EM VII clonal apple rootstocks in 1970 were reduced by 1.5 ppm soil-incorporated dichlobenil. Concentrations of 6.0 ppm and higher prevented growth.
No leaf margin yellowing (LMY) was observed in 1970, but in 1971 it occurred following placement of 3 clonal rootstocks outdoors. EM VII produced the most shoot growth and EM IX the least. EM IX produced the least fresh wt increase, while those of EM VII and MM 106 were equivalent. EM VII had more LMY than the other 2 rootstocks.
The responses of the 3 rootstocks to several concn of dichlobenil were similar. Dichlobenil concn of 0.2 and 0.4 ppm increased fresh wt, largely due to stimulation of root growth. Concentrations of 0.8 ppm and more of dichlobenil suppressed growth.
Abstract
2-Chloro-9-hydroxyfluorene-9-carboxylic acid (chlorflurenol) 3 at 50 or 100 ppm increased fruit production of a gynoecious cucumber (Cucumis sativus L. cv. MSU 713-5) under field conditions of both normal and reduced pollination. A monoecious cultivar, ‘Wisconsin SMR 18’, treated with (2-chloroethyl) phosphonic acid (ethephon) and then chlorflurenol produced over twice as many fruit as the control when pollen was plentiful, and more than 4 ⨯ as many when pollen supply was limited. Ethephon sprays alone increased pistillate flower formation on the monoecious cultivar but did not increase fruit set. Chlorflurenol treatments increased the proportion of fruit in the smaller, more valuable size grades and appear advantageous for mechanically harvested pickling cucumbers.
Abstract
Nomenclature rules are proposed for naming genes of species in the Cucurbitaceae. Genes of cucumber, muskmelon, watermelon, squash, and other cucurbits are reviewed and, when necessary, changes in gene symbols are proposed. The number of known qualitative factors include 68 genes for the cucumber, 37 for muskmelon, 25 for watermelon, and 30 for Cucurbita species.