Genes for Resistance to Zucchini Yellow Mosaic in Tropical Pumpkin

Abstract

Four cultigens of Cucurbita moschata resistant to zucchini yellow mosaic virus were crossed with the susceptible 'Waltham Butternut' and with each other in order to clarify the mode of inheritance of resistance and relationships among the genes involved. Five loci were segregating, with genes for resistance Zym-0 and Zym-4 carried by 'Nigerian Local' and one of them also carried by 'Nicklow's Delight,' Zym-1 carried by 'Menina,' and zym-6 carried by 'Soler.' A recessive gene carried by 'Waltham Butternut,' zym-5, is complementary with the dominant Zym-4 of 'Nigerian Local,' that is, the resistance conferred by Zym-4 is only expressed in zym-5/zym-5 individuals. Gene zym-6 appears to be linked to either Zym-0 or Zym-4, and it is also possible that Zym-1 is linked to one of them as well.

Phenotypic and marker‐assisted pyramiding of genes for resistance to zucchini yellow mosaic virus in oilseed pumpkin (Cucurbita pepo)

“…The other, Zym‐4, confers resistance only in the homozygous presence of a third, recessive gene, zym‐5, carried by ‘Waltham Butternut’ (Pachner et al. ). The other population was obtained by crossing the susceptible oilseed pumpkin ‘SZG1’ ( C. pepo subsp.…”

“…Growing conditions, preparation of the virus inoculum and inoculation method have been described by Pachner et al. (). In each experiment, 12 or more plants of the susceptible Cucurbita moschata ‘Waltham Butternut’ or the susceptible C. pepo oilseed pumpkin ‘Gleisdorfer Ölkürbis’ or ‘Retzer Gold’ were grown as controls.…”

“…, Pachner et al. ). The monetary value of C. pepo has spurred intensive efforts dedicated to introgressing resistance from C. moschata .…”

“…Seven gene loci in Cucurbita moschata have been identified to confer resistance to ZYMV (Pachner et al. ). ‘Nigerian Local’ carries two genes for resistance, designated Zym‐0 and Zym‐4 , but the latter confers resistance only in complementary interaction with the recessive gene designated zym‐5, carried by the ZYMV‐susceptible ‘Waltham Butternut’.…”

Control of Cucurbit Viruses

“…No resistance has been found in C. pepo or in C. maxima but accessions of several wild species or C. moschata (Nigerian local, Menina) are resistant to the virus (Paris, Cohen, Burger, & Yoseph, 1988;Provvidenti, 1986). One main dominant gene (Zym-1) and several complementary genes have been described in Menina and Nigerian local (Gilbert-Albertini, Lecoq, Pitrat, & Nicolet, 1993;Pachner, Paris, & Lelley, 2011;Paris et al, 1988). In commercial zucchini squash cultivars, Zym-1 confers tolerance which allows good levels of fruit production even when ZYMV epidemics occur.…”