Genetic variation is essential for crop breeding. In classical plant breeding programme, variation is generated by hybridization and selections are made from the resulting segregating generations. Induced mutagenesis can supplement hybridization or able to replace as a source of variability. Since, mutations bring about variation, they provide the ultimate basis for evolution of new forms, varieties or species. Induced and spontaneous mutations have played an important role in developing improved cultivars of various fruit crops as a supplementary method to conventional breeding. But, induced mutations also have well defined limitations in fruit breeding applications, but their possibilities may be expanded by the use of in vitro mutation techniques.

Background: Papaya (Carica papaya L.) belonging to Caricaceae family has long been recognized as a wonder fruit of the tropics and grown predominantly for its delicious taste and extraction of its digestive constituent papain. As vegetative growth and flowering is simultaneous in this crop, supply of requisite amount of nutrients is necessary during the active growth period, which is possible through fertigation. Knowledge on correct dose of fertilizers to be provided through fertigation is very crucial. Methods: A field experiment was conducted during the period 2018-2020 at Instructional Farm, College of Agriculture, Vellayani, Thiruvananthapuram to investigate the response of fertigation and foliar spray on yield and fruit quality of papaya variety Surya. The experiment was laid out in randomised block design with combination of four fertigation doses of 75%, 100%, 125% and 150% RDF of N and K and three foliar sprays (1% 19:19:19, 0.5% ZnSO4+0.3% borax and water spray) which where compared with soil application of recommended dose of NPK (control 1) and soil application of NPK plant-1 year-1 based on soil test data as organic manures as combination of FYM, poultry manure and vermicompost in the ratio of 2:1:1 (control 2). Result: The findings of the study revealed that application of 100% RD of N and K through fertigation at weekly interval from one MAP to 20 MAP and foliar sprays of 0.5% ZnSO4 and 0.3% borax at 4th, 8th, 12th and 16th MAP (T5) along with basal application of 850 g rock phosphate and 15 kg FYM improved the yield and fruit quality parameters and can be recommended for commercial papaya cultivation.