Effect of treating onion plants with fungicides on the predisposition of the produced seeds to smut infection

Effect of treating onion plants with fungicides on the predisposition of the produced seeds to smut infection

1983

SB339.O5REP-0119

Treating onion plants with fungicides during the vegetative growth, predisposed the produced seeds to infection with smut. Systemic fungicides (Bavistin, Benlate, Sumisclex, and Topsin) were more effective than the nonsystemic (Allisan). The most effective systemic fungicide was Bavistin followed by Benlate or Sumisclex, whereas Topsin was the least effective. Onion seed predisposition to infection with smut increases as the rate of fungicide was increased. Seeds of onion plants treated with Allisan, Benlate or Bavistin during the vegetative growth, constitute higher amounts of reducing, non-reducing, and total sugars, as well as less amounts of free phenols as compared with untreated onion plants. Amounts of conjugated, and total phenols decreased in seeds of onion plants treated with Allisan and Benlate, whereas these compounds increased in seeds from plants treated with Bavistin. Amounts of phenolic compounds in seeds of plants treated with the higher rate of fungicide were lesser than that of the lower rates. Using fungicides on onion plants, raised also the total free amino acids in the seeds produced from these plants. Some amino acids were decreased, while some other amino acids were increased with raising the rate of Allisan. On the other hand, the higher rate of Bavistin decreased Serine, Glutamine, Alanine, Tyrosine, and Valine. Fungicides used on onion plants during the vegetative growth caused marked changes in sugars, phenols, and free amino acids in eight days old seedlings obtained from seed of these plants and grown in distilled water. Sugars (reduced, non-reduced, and total) increased with the use of fungicides. Bavistin was the most effective fungicide followed by Benlate or Sumisclex, whereas Allisan was the least effective. Sugars rate of fungicide increased. Free phenols decreased with all fungicidal treatments. Total and conjugated phenols increased only with Bavistin treatment. The higher rates of fungicides reduced the phenolic compounds to leasser amounts as compared with lower rates. Total free amino acids decreased with Allisan and increased with Bavistin treatments. Amounts of amino acids changed according to fungicidal treatment. [AS]

v.61(2):55-71, AGRICULTURAL RESEARCH REVIEW

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