Breeding for resistance to onion downy mildew caused by<i>Peronospora destructor</i>

Jones, Howard A.; Porter, D. R.; Leach, L. D.

doi:10.3733/hilg.v12n09p531

Cited by 11 publications

(8 citation statements)

References 3 publications

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“…to record the seed yield of these plots. In my opinion, however, the results from this experiment corroborate the opinion of Jones, Porter, and Leach (29) that leaf pruning does not seriously interfere with seed production. As to whether such treatments will reduce the severity of downy mildew, apparently no information is available, but in cases of severe leaf infection the removal of the leaves would, certainly reduce the amount of inoculum.…”

Section: Feb 1943]supporting

confidence: 83%

“…plantings vary from none to total failure. According to Jones, Porter, and Leach (29), the loss due to mildew infection in the California seed crop from 1920 to 1938 has varied f'rom 0 to 70 per cent in different years. I have seen individual fields of onions for greens, bulbs, and seed 14,No.…”

Section: Amount Of Losses-losses From Onion Mildew In Individual Fieldmentioning

confidence: 99%

“…Varietal Susceptibility.-AII commercial varieties of the common onion, Allium Cepa, are believed to be susceptible to downy mildew, though some varieties are more severely injured than others, and the development by hybridization of varieties with a high degree of resistance is under way (29). The mildew susceptibility of several commercial onion varieties grown for seed and for bulbs was studied in field plantings at Davis, Berkeley, and Milpitas, and in greenhouse plantings at Berkeley.…”

Section: Amount Of Losses-losses From Onion Mildew In Individual Fieldmentioning

confidence: 99%

“…and Leach (29) and used by them in a breeding program aimed at the development of mildew-resistant onions. Among the susceptible varieties White Persian and Yellow Bermuda are outstanding, and mildew has been so severe as to make seed production of these varieties impractical at Milpitas.…”

Section: G05mentioning

confidence: 99%

“…The leaves of well-established plants started from bulbs and grown for seed are apparently of little importance in determining the seedyielding capacity of those plants. Jones, Porter and Leach (29) report the use of leaf pruning as a method of reducing the spread of mildew. While they give no evidence that the leaf pruning did actually reduce the incidence of mildew, they report that a good crop of seed was produced by the treated plants.…”

Section: Introductionmentioning

confidence: 99%

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Onion downy mildew

Yarwood¹

1943

Hilg

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, and Riverside counties, onion mildew has been observed in destructive amounts but has attracted less attention than in the other districts mentioned. In California, onion seed is harvested in July and August on plants grown from mature dormant bulbs which were set in the ground the previous fall and winter. The seed-producing plants make most of their vegetative growth in the spring months, which are during the rainy season, and produce their flowers and mature their seed in the semiarid summer weather that follows. This coincidence of the vegetative-growth period with the cool, rainy season, while apparently favorable for onion growth and for high yields (28) in seasons of relative freedom from mildew, may be associated with the destructive onion-mildew epidemics that occasionally occur. NAME, HISTORY, AND RANGE OF THE DISEASE Onion downy mildew has also been called mildew, mold, blight, white blast, and rust, but the name downy mildew is preferred formyeologieal arid symptomatological reasons. Onion downy mildew was first reported in England in 1841 by Berkeley (1), but no information concerning its importance was presented at that time. Since then it has been studied intensively in the Bermuda Islands by Shipley (60) ; in New York by Whetzel (76), Cook (12), and Newhall (50); in Ireland by Murphy and McKay (44), and McKay (36) ; in Russia by Katterfeld (31); and in California by Jones, Porter, and Leach (29). In addition to the regions already mentioned, the disease is present in Asia (10), Africa (73), Australia (51), New Zealand (32), and Argentina in South America (34). With the possible exception of limited localities of unfavorable environment for the disease such as Texas (65), onion downy mildew is now considered general in its distribution. ECONOMIC IMPORTANCE Nature of Losses.-Onion downy mildew is important because of the large reductions in yield caused by the disease in epidemic seasons. With onions for greens, the yield reduction is direct-the injury to and killing of the leaves caused by mildew infection reduces the yield and salability of the product. Occasionally plants are killed but this is apparently rare. With onions for bulbs, the loss is indirect-mildew injury to the leaves reduces the yield and quality of bulbs. According to Murphy and

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Section: Feb 1943]supporting

confidence: 83%

Section: Amount Of Losses-losses From Onion Mildew In Individual Fieldmentioning

confidence: 99%

Section: Amount Of Losses-losses From Onion Mildew In Individual Fieldmentioning

confidence: 99%

Section: G05mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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