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

Chinur Hadi Mahmood1&  Caser Gaffer Abdel2

1 Univ. of Sulaimani, College of Agricultural Sciences, Horticulture Dept. Kurdistan Region-Iraq

2Univ. of Muthanna, College of Agriculture, Combat desertification Dept.


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-1B 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-1B highly exceeded 75mg.l-1B 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.                                                                                                                                      

Key Words: Lettuce Seeds, head folding, Boron, mulching, bitterness.


 [1] Funk, V.A., Bayer, R.J., Keeley, S., Chan, R., Watson, L., Gemeinholzer, B., Schilling, E., Panero, J.L., Baldwin, B.G., Garcia-Jagas, N., Susanna, A., Jansen, R.K.  "Everywhere but Antarctica: Using a supertree to understand the diversity and distribution of the Compositae", Biol. Skr., Vol.(55), pp. 343-374. (2005).

[2] Abbott, A. "The isolation of flowering time genes from lettuce to enable the manipulation of bolting time", PhD Dissertation in Plant and Environmental Sciences, University of Warwick, Warwick HRI. (2010).

[3] Ryder. E.J. The New Salad Crop Revolution, Trends in new crops and new uses,  J. Janick and A. Whipkey (eds.),. ASHS Press, Alexandria, VA. p. 408–412. (2002).

[4] Boriss, H.  and Brunke, H. Agricultural Issues Center”, (2012). http://www.agmrc.org/commodities products/vegetables/lettuce-profile.

[5] Boriss, H. and Specialist. J. Commodity Profile: Lettuce, Agricultural  Issues Center University of California, Pp. 1-7. (2005).

[6] Goldbach, H. E. and Wimmer M. A. "Boron in plants and animals: Is there a role beyond cell-wall structure", Journal of Plant Nutrition and Soil Science, Vol.(170), pp, 39–48. (2007).

[7] Sessa, R.A. ,  Bennett, M.H.,  Lewis, M.J.,  Mansfield, J.W.,  and Beale M.H. "Metabolite profiling of sesquiterpene lactones from Lactuca species", J. Biol. Chem., Vol. (275), pp. 26877-26884.(2000).

[8] Price, K.R., Dupont, M.S., Shepherd, R., Chan, H.W.S. and G.R. "Fenwick. Relationship between the chemical and sensory properties of exotic salad crops-colored lettuce (Lactuca sativa) and chicory (Cichorium intybus) ", J. Sci. Food Agr, Vol.(53), pp.185–192. (1990).

[9] Bennett, M.H., Mansfield, J.W. Lewis, M.J. and Beale, M.H. "Cloning and expression of sesquiterpene synthase genes from lettuce (Lactuca sativa L.) ", Phytochemistry, Vol. (60), No.3, pp.255-261. (2002).

[10] Samuel A. Contreras, B.S. Effect of Material Plant Environment On Lettuce (Lactuca sativaL.)Seed Dormancy, Germinability and Storability (Dissertation), The Ohio State University. (2007).

[11] Valde´s, V.M., Bradford, K.J. and Mayberry, K.S. "Alleviation of thermodormancy in coated lettuce seeds by seed priming", Hort. Science, Vol.(20), pp.1112–1114. (1985).

[12] Copeland, L.O. and McDonald. M.B. Principles of seed science and technology, Kluwer Academic Publishers, Boston.U.S.A. (2001).

[13] Simonne, A., Simonne, E.,  Eitenmiller, R. and Coker, C.H. "Bitterness and composition of lettuce varieties grown in the southeastern United States", Hort. Technology, Vol.(12), pp.721–726. (2002).

[14] SAS Institute, Inc. The SAS system, Relase 6.12. Cary, NC. (1996).

[15] Ryan, J., George, E. and Abdul,  R. Soil and Plant Analysis Laboratory Manual, 2nd Edition. Jointly published by the International Center for Agricultural. Research in the Dry Areas (ICARDA) and the National Agricultural Research Center (NARC). Available from ICARDA, Aleppo, Syria.172 pp. (2001).

[16] Chapman, H.D. and Pratt, P.F. Methods of analysis for soils, plants and water, Univ. California, Berkeley, CA, USA. (1961).

[17] Lin, C.S. and Binns, M.R., "A superiority measure of cultivar performance for cultivar + location data", Can. J. Plant Sci., Vol. 68, pp. 193–198. (1988).

[18] Martin, C.A. and Ingram, D.L. "Temperature dynamics in black poly containers", Proc. Southern Nurserymen’s Assoc. Res. Conf., Vol.33, pp.71-74. (1988).

[19] Ruter, J.M. "Evaluation of Tex-R Agroliners for Bag-in-Pot Production", Proc. Southern Nurserymen’s Assoc. Res. Conf., Vol.(42), pp.162-164. (1997).

[20] Ruter, J.M. and Ingram, D. L. "High Root-zone temperatures influence RuBisCo activity and pigment accumulation in leaves of ‘Rotundifolia’ Holly", J. Amer. Soc. Hort. Sci., Vol.(117), pp.154-157.(1992).

[21] Levitt, J. Responses of Plants to Environmental Stresses, Vol.71, 2nd ed. Academic Press, NY.U.S.A. (1999).

[22] Ruter, J.M. "The Practicality of Pot-In-Pot", American Nurseryman, Vol.(8), No.2, pp.32-37. (1997).

[23] Johri, B.M. and  Vasil, I.K. "Physiology of pollen", Bot. Rev., Vol. (27), pp.325–81. (1961).

[24] Jackson, J.F. "Borate control of energy-driven protein secretion from pollen and interaction of borate with auxin or herbicide—a possible role for boron in membrane events", Vol.(99), pp. 221– 229. (1991).

[25] Vaughan, A.K.F. "The relation between the concentration of boron in the reproductive and vegetative organs of maize plants and their development", Rhod. J. Agric., Vol. 15, pp.163–70. (1977).

[26] Kraus, H.T., Mikkelsen, R.L. and Warren, S.L. "Container substrate temperatures affect mineralization of composts", Hort. Science, Vol.(35), pp.16-18. (2000).

[27] Mengel, K. and Kirkby, E.A. Principles of  Plant Nutrition, 4th Edition. Switzerland, International Potash Institute. (1987).

[28] Clarkson, D.T. and Warner. A.J. "Relationships between air temperature and transport of ammonium and nitrate ions by Italian and perennial ryegrass", Plant Physiol., Vol.(64), pp. 557-561. (1979).

[29] Haynes, R.L. Mineral nitrogen in the plant-soil system, 2nd ed. Academic Press, Orlando, Fla. Heckathorn. (1986).

[30] Lovatt, C.J. and Dugger, W.M. Boron, The Biochemistry of the Essential Ultra Trace Elements, ed. E Frieden, New York: Plenum.U.S.A. pp. 389–421. (1984).