Emotions can't be adequately expressed in words. The author's acknowledgement is more than what he has expressed here. Indeed the words at my command are not adequate to convey the depth of my feeling and gratitude to my Major Advisor Dr. M. M. Patel, Professor and Head, Principal, C.P. college of Agriculture, member of advisory committee for their encouragement and ever willing help of various kind during the course of investigation. On this occasion words fail to express my profound reverence, heartfelt gratitude and deep seated obligation to my adorable late father "Shri Jitabhai" and my mother"Mrs. Jatanben," my wife "Savita" son "Nirmal" and Daughter "Payal" for their, constant encourgement, blessings, everlasting love and personal sacrifice at every stage of my studies. - DESAI LALJI J.