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The Influence of Mulching and GA3+Iron Mixture on Head Folding,Bitterness and Quality of Produced Seeds of Lettuce Lactuca sativa var. Longifolia cv. Marul.

Chinur H. Mahmood1 and Caser G. Abdel2

1 University of Sulaimani, Facultry of Agricultural Sciences, Horiculture Dept. Kurdistan Region-Iraq
2 University of Dohuk, College of Agriculture, Horiculture Dept. Kurdistan Region – Iraq

This study was carried out during the period between November, 2013 and August, 2014
to decrease unfolding, bitterness and tip burns through adopting a new screening method
and to produce lettuce seeds and head yields of high qualities. Seeds and plants raised
from them were treated with mixtures of [0 and 10 mg.l-1 GA3 + 25 mg.l-1 Fe, 10 mg.l-1
GA3 + 50 mg.l-1 Fe and 10 mg.l-1 GA3+ 75mg.l-1 Fe]. Plants grown on mulched and
unmulched soils. Mulched soil plants displayed superiority over bare soil in terms:
number of unfolded leaves, stem length and leaves number by 48.75, 110.85 and
22.23%, respectively. However, unmulched soil bypassed mulched soil in T.S.S. and dry
matter percentages of folded leaves, unfolded leaves, stem and folded leaf base (23.96,
19.41, 30.59, 22.17, 18.52, 28.6, 18.54 and 27.24%, respectively). Lettuce grown on
mulched soil revealed superiority over that grown on bare soil in N content of folded and
unfolded leaves (23.1 and 68.75%, respectively), K content of folded leaves, stem and
folded leaf base (57.85, 42.02 and 24.43%, respectively), Fe content of stem and folded
leaf base (106.11 and 54.02, respectively), Ca content of folded leaves, unfolded
leaves, stem and folded leaf base (424.09, 235.96, 206.02 and 296.78%, respectively). 10
mg.l-1 GA3 + 75 mg.l-1 Fe displayed preponderance over untreated plants in head fresh
weight (26.43%), head yield (26.16%), TSS (15.52%), branches number after chopping
(92.9%), branch heights (66.98%) leaf number (30.82%), B content of folded leaves and
stem (143.23 and 57.89%, respectively), N content of the folded leaf base (49.73%), K
content of folded leaves (7.15%), Fe content of stem (152.14%) and Cu content of stem
(39.54%). Lettuce plant treated by 10 mg.l-1 GA3 + 50 mg.l-1 Fe grown on mulched soil
overwhelmed other dual interaction treatments as it showed the highest values in head
fresh weight (821 g), head yield.m-2 (4.93 kg), weight of folded leaves (483.75 g),
number of unfolded leaves (23.75) and weight of unfolded leaves (335 g).

Key Words: Mulching, GA3+Iron Mixture, Lettuce seed


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