The influences of reduced water evaporation, Gibberellic acid (GA3) on screening lettuce (Lactuca sativa L. var. longifolia cv. Marul) for lowest heading failure, tipburns and bitterness

Abstract

Two experiments were included in this investigation where Marul lettuce seeds and plants raised from these seeds were treated with GA₃ rates of 0, 5, 10 and 15 mg.l^-1 in first season to represent experiment1. Experiment 2 was an extending to experiment 1 to include black polyethylene mulch and bare soils to reduce water evaporation. Experiment 1 results revealed that 15mg.l^-1 GA₃ was the most potent rate; it highly exceeded untreated check plants in terms of fresh weight of folded leaves (108.99%), stem length (43.62%) and stem dry weight (6.74%). 5mg.l^-1 GA₃ was the paramount treatment over others in nutrient content of leaves. It significantly exceeded untreated in stem Na content (5.52%), Na in the base of folded leaves (46.22%), Ca content in folded leave (251.48%), Ca content of unfolded leaves (206.57%), Ca content of stem (321.65), Ca content of folded leaves bases (280.59%), Fe content of folded leaves (141.46%), Fe content of unfolded leaves (84.98%) and Fe content of folded leaves base (104.12%), K content in folded leaves (65.65%), K content in unfolded leaves (66.51%) and K content in folded leaves bases (61.74%). This treatment also showed superiority over 10mg.l^-1 GA₃ in Na content of stem (16.16%), Na content of folded leaves bases (8.62%), N content in folded leaves (53.57%), Ca content of unfolded leaves (128.2%), Ca content of stem (156.5%), Ca of folded leaves bases (113.18%), Cu content of stem (412.8%), Fe content in folded leaves (36.26%), Fe content in unfolded leaves (237.21%), Fe content in folded leaves bases (144.96%), K content in folded leaves (40.94%), K content in unfolded leaves (9.33%) and K in folded leaves bases (23.53%). Experiment2 results manifested that unmulched plants significantly exceeded that of mulched in fresh weight of heads (51.5%), fresh head yield.m^-2 (51.47%), weight of folded leaves (31.19%), number of unfolded leaves (102.03%), weight of unfolded leaves (87.38%), stem length (55.43%), height of branches formed after chopping (14.61%). However, mulched treatment showed superiority over unmulched only in leaf number on stem (23.56%). Unmulched treatment significantly exceeded that of mulched in boron (B) content of folded leaves (237.42g.Kg^-1), B content in unfolded leaves (149.11%), B content in stem (138.99%), B content in folded leaf base (182.93%) and Fe in folded leaves (86.93%). In contrast to growth, seeds yield showed positive response to black polyethylene mulch.15 mg.l^-1 GA₃ treated plants highly exceeded their corresponding plants of check in stem diameter, branch number after chopping, branch heights and number of leaves on stem by 12.65, 62.19, 178.19 and 93.42%, respectively. It also revealed superiority over control in leaf accumulation of B content in unfolded leaves (17.48%), N content in stem (10.67%), K content in folded leaves (12.53%), Na content of folded leaves (103.85%), Fe content in folded leaves (32.93%), Ca content in folded leaves (35.06%), unfolded leaves (155.44%) and folded leaf base (36.33%). Heading failure, tipburns and bitterness were completely negated in the second season with screened seeds.

Writer

Dr. Caser G. Abdel

Send to Cario University cientific Conference.Dr CASER GHAAFAR ABDEL (Vegetable production/ Water stress Physiology) Personal Data البيانات الشخصيه Surname: ABDEL Forenames: CASER GHAAFAR Gender: Male Marital Status: Married. متزوج Date and Place of Birth: On July 1st 1953, Jadidat Al-Shat, Hibhib, Khalis, Deyala Iraq Nationality: Iraqi Academic Status: Professor Assistance Languages: Arab (mother tongue), English (spoken and written) Address for Correspondence: Horticulture Department, Agriculture College, Dohuk University, Dohuk, Kurdistan Region, Iraq.

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