Response of Imbibing lettuce (Lactuca sativa var.longifolia)cv. Marul Seeds to Boron levels and mulching on head folding, bitterness and quality of produced seeds

Original: 22/12/2017 Revised: 11/01/2018 Accepted: 06/02/2018 Published online: The objective of this study was to reduce unfolding, bitterness and tip burns through adopting a new screening method to produce lettuce seeds and head yields of high qualities, to achieve these goals lettuce seeds and plant raised from them were treated with Boron and grown on bare and black polyethylene mulched soil at rates of 0, 25, 50 and 75mg.l -1 . Lettuce plants grown on bare soil profoundly exceeded that grown on black polyethylene mulched soils in head fresh weight by (20.3%), head yield (20.65%), folded leaves number (25.1%), stem length (78.98%), branches number after chopping (11.32%) and leaves number on stem (42.94%).Lettuce plant treated with 50mg.l -1 B profoundly exceeded untreated plants in stem length, T.S.S of folded leaves, stem and folded leaf base by (29.33, 35.36, 42.96 and 23.2%) respectively. The rate 50mg.l -1 B highly exceeded 75mg.l -1 B in stem length, T.S.S of stem and folded leaf base by (20.66, 25.84, and 15.18%) respectively, It also surpassed the other treatment in stem diameter (32.26, 23.87, and 20.94%), respectively. The rate 25 mg.l -1 B treatment showed superiority over other treatments, since it highly exceeded untreated and 50 mg.l -1 B in seeds yield.plant -1 and seed yield.m -2 by (53.63%). Moreover, it highly exceeded profoundly 75 mg.l -1 B in seeds yield.plant -1 and seed yield.m -2 by (166.98%). Lettuce plants treated with 75mg.l -1 and grown on bare soils was the best dual interaction as compared to other. It showed the highest values or very close to the highest ones in head fresh weight, head yield.m -2 , number of folded leaves, weight of folded leaves, TSS of folded leaves and branches height by (750g, 4.5Kg, 41.25, 440g, 6.8% and 54cm) respectively. Lettuce plants treated with 75mg.l -1 B, grown on bare soils was the best dual interaction compared to others.