A reliable system for the transformation of cantaloupe charentais melon (Cucumis melo L. var. cantalupensis) leading to a majority of diploid regenerants

An efficient system of transformation leading to a majority of transformed diploid plants from leaf explants of Cucumis melo L. var. Cantalupensis (cv. Védrantais) was developed. Several regeneration protocols using cotyledon or leaf explants were analysed with particular emphasis on the regeneration efficiency and the ploidy level of the regenerated melon plants. The use of leaf explants excised from 10 day-old seedlings, cultured in Murashige and Skoog's medium supplemented with 1 mM 6-benzylaminopurine (BAP) and 1 mM 6-(g,g-dimethylallylamino)-purine (2iP), resulted in a high regeneration frequency (73%). In these conditions, more than 84% of the regenerated plants were found to be diploid. Addition of an Agrobacterium-mediated transformation step did not significantly change the percentage (81.8%) of diploid plants regenerated. This protocol was successfully used to produce diploid transgenic melon plants expressing the antisense ACC oxidase gene, encoding ACC oxidase which catalyses the last step of ethylene biosynthesis. Ethylene production and ACC oxidase activity of the leaf explants from transgenic plants was reduced by more than 80% as compared to the control untransformed tissues. This transformation/ regeneration method could be routinely used for the introduction of other genes of interest in melon

Allelopathic effects of Juglone and decomposed walnut leaf juice on muskmelon and cucumber seed germination and seedling growth

In this study, effects of juglone and decomposed walnut leaf juice on muskmelon (Cucumis melo cv. Galia) and cucumber (Cucumis sativus cv. Beith Alpha) seed germination percentage and postgerminationseedling growth were investigated. Decomposition was carried out by keeping the leaves in distilled water. Muskmelon and cucumber seeds were germinated in Petri dishes at 25°C. Seed germination, seedling elongation and weights were determined at day 10. No significant effect of juglone and decomposed walnut leaf juice on muskmelon seed germination percentage was observed. However, germination of cucumber seed was inhibited significantly. It was found that while both the dry weight root and stems elongation of muskmelon and cucumber seedlings were affected negatively by juglone and undiluted decomposed walnut leaf juices. The negative effect decreased as dilution ratios of decomposed leaf juice increased

Management Of Bacterial Wilt On Muskmelon Using Actigard

Bacterial wilt of muskmelon caused by Erwinia trachephila (E.F. Smith), is one of the most important diseases of cucurbits, particularly muskmelon, in the world. This pathogen is transmitted by the striped cucumber beetle,Accalyma vittatum (F.), and causes serious economic losses in fruit yield and quality. Control of this disease is usually accomplished by applying insecticides to kill the beetles before disease transmission occurs. The goal of this study was to reduce the bacterial wilt incidence or beetle feeding on muskmelon using an alternative control method, the plant activator acibenzolar-S-methyl (Actigard) ® . The potential for using acibenzolar-S-methyl as a foliar spray was evaluated by using different rates, number of applications and timing of Actigard ® compared with standard insecticides. Muskmelon plants treated with Actigard® at a concentration of 28.3g per acre 6 times had a significant reduction in plant vigor and yield. Actigard® treatment at the recommended concentrations (28.3g and14.17. per acre) did not reduce bacterial wilt severity or incidence. Likewise, Actigard ® did not kill striped cucumber beetles or reduce their populations on muskmelon plants. These results suggest that acibenzolar-S-methyl (Actigard) ® does not offer a viable alternative to managing bacterial wilt with pesticides

Role of ethylene on various ripening pathways and on the development of sensory quality of Charentais cantaloupe melons

Charentais melons (Cucumis melo L., var cantalupensis Naud.) in which ethylene biosynthesis has been suppressed by an antisense ACC oxidase gene have been used to better understand the role of ethylene in the regulation of the ripening process of climacteric fruit and on the development of sensory qualities. We have shown that a number of biochemical and molecular processes associated with the ripening of climacteric fruit are ethylene-independent. In some cases, such as softening of the flesh, the same pathway comprises both ethylene-dependent and -independent components. The various ethylene-dependent events exhibit differential sensitivity to ethylene. The threshold level for degreening of the rind is 1 ppm, while 2.5 ppm are required to trigger the ethylene-dependent component of the softening process. The saturating level of ethylene for all these events is less than 5 ppm, which is by far lower than the internal ethylene concentrations found in the fruit at the climacteric peak (around 100 ppm). Detachment of the fruit influences the development of respiratory climacteric. Fruit remaining attached to the vine, although producing higher levels of ethylene, exhibit a reduced climacteric rise in respiration as compared to detached fruit. The response of antisense ACO fruit to exogenous ethylene in terms of respiration is higher in detached than in attached fruit. Ethylene-suppressed melons show a severe reduction of aroma volatiles production, particularly in ester production. In the biosynthetic pathway of aliphatic esters, the dehydrogenation of fatty acids and aldehydes appears to be ethylene-dependent. In contrast, alcohol acetylation comprises ethylene-dependent and ethylene-independent components, probably corresponding to differentially regulated alcohol acetyl transferases. In terms of sensory quality, these data show that the extension of shelf-life through the inhibition of ethylene production has some beneficial effects on texture and sugar accumulation but is detrimental for the generation of aroma

Vol. 10, No. 19, Nov. 11, 2004: Illinois Fruit and Vegetable News

published or submitted for publicationnot peer reviewe

Home Gardening

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Genetics Analysis and Heritability of Fruit Characters in Muskmelon (Cucumis Melo L.) Using Extreme Parental Differences

Taeng-Thai is the Thai name for oriental pickling melon or muskmelon (Cucumis melo L.) which is a Cucumis species. Based on consumption as Thai traditional dessert, fruit characters at ripening stage are very important to improve the muskmelon cultivar. Understanding the genetic control of fruit traits is the key to a successful for crop improvement. Research aimed to determine the genetic effects, number of genes and heritability of fruit characters in muskmelon. The results have shown that both additive and dominant effects governed for fruit weight, fruit length, fruit width and fruit thickness with the number of gene as 40.26, 1.55, 10.70 and 11.10 genes, respectively. Simple phenotypic correlation coefficients shown, had a significant positive correlation among the four fruit traits. Due to the quantitative inheritance of fruit characters, quantitative traits loci (QTL) mapping of those traits were necessary to identify all controlling genes of fruit traits in further muskmelon improvement

Pesticide Use on Fruit and Vegetable Crops in Ohio 1990

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